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Cafaro A, Schietroma I, Sernicola L, Belli R, Campagna M, Mancini F, Farcomeni S, Pavone-Cossut MR, Borsetti A, Monini P, Ensoli B. Role of HIV-1 Tat Protein Interactions with Host Receptors in HIV Infection and Pathogenesis. Int J Mol Sci 2024; 25:1704. [PMID: 38338977 PMCID: PMC10855115 DOI: 10.3390/ijms25031704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/19/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024] Open
Abstract
Each time the virus starts a new round of expression/replication, even under effective antiretroviral therapy (ART), the transactivator of viral transcription Tat is one of the first HIV-1 protein to be produced, as it is strictly required for HIV replication and spreading. At this stage, most of the Tat protein exits infected cells, accumulates in the extracellular matrix and exerts profound effects on both the virus and neighbor cells, mostly of the innate and adaptive immune systems. Through these effects, extracellular Tat contributes to the acquisition of infection, spreading and progression to AIDS in untreated patients, or to non-AIDS co-morbidities in ART-treated individuals, who experience inflammation and immune activation despite virus suppression. Here, we review the role of extracellular Tat in both the virus life cycle and on cells of the innate and adaptive immune system, and we provide epidemiological and experimental evidence of the importance of targeting Tat to block residual HIV expression and replication. Finally, we briefly review vaccine studies showing that a therapeutic Tat vaccine intensifies ART, while its inclusion in a preventative vaccine may blunt escape from neutralizing antibodies and block early events in HIV acquisition.
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Affiliation(s)
- Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, 00161 Rome, Italy; (I.S.); (L.S.); (R.B.); (M.C.); (F.M.); (S.F.); (M.R.P.-C.); (A.B.); (P.M.)
| | | | | | | | | | | | | | | | | | | | - Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, 00161 Rome, Italy; (I.S.); (L.S.); (R.B.); (M.C.); (F.M.); (S.F.); (M.R.P.-C.); (A.B.); (P.M.)
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2
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T-cell evasion and invasion during HIV-1 infection: The role of HIV-1 Tat protein. Cell Immunol 2022; 377:104554. [DOI: 10.1016/j.cellimm.2022.104554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 12/22/2022]
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Ensoli B, Moretti S, Borsetti A, Maggiorella MT, Buttò S, Picconi O, Tripiciano A, Sgadari C, Monini P, Cafaro A. New insights into pathogenesis point to HIV-1 Tat as a key vaccine target. Arch Virol 2021; 166:2955-2974. [PMID: 34390393 PMCID: PMC8363864 DOI: 10.1007/s00705-021-05158-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/09/2021] [Indexed: 02/07/2023]
Abstract
Despite over 30 years of enormous effort and progress in the field, no preventative and/or therapeutic vaccines against human immunodeficiency virus (HIV) are available. Here, we briefly summarize the vaccine strategies and vaccine candidates that in recent years advanced to efficacy trials with mostly unsatisfactory results. Next, we discuss a novel and somewhat contrarian approach based on biological and epidemiological evidence, which led us to choose the HIV protein Tat for the development of preventive and therapeutic HIV vaccines. Toward this goal, we review here the role of Tat in the virus life cycle as well as experimental and epidemiological evidence supporting its key role in the natural history of HIV infection and comorbidities. We then discuss the preclinical and clinical development of a Tat therapeutic vaccine, which, by improving the functionality and homeostasis of the immune system and by reducing the viral reservoir in virologically suppressed vaccinees, helps to establish key determinants for intensification of combination antiretroviral therapy (cART) and a functional cure. Future developments and potential applications of the Tat therapeutic vaccine are also discussed, as well as the rationale for its use in preventative strategies. We hope this contribution will lead to a reconsideration of the current paradigms for the development of HIV/AIDS vaccines, with a focus on targeting of viral proteins with key roles in HIV pathogenesis.
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Affiliation(s)
- Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
| | - Sonia Moretti
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Alessandra Borsetti
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Maria Teresa Maggiorella
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Stefano Buttò
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Orietta Picconi
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Antonella Tripiciano
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Cecilia Sgadari
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Paolo Monini
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
| | - Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy
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Tripiciano A, Picconi O, Moretti S, Sgadari C, Cafaro A, Francavilla V, Arancio A, Paniccia G, Campagna M, Pavone-Cossut MR, Sighinolfi L, Latini A, Mercurio VS, Pietro MD, Castelli F, Saracino A, Mussini C, Perri GD, Galli M, Nozza S, Ensoli F, Monini P, Ensoli B. Anti-Tat immunity defines CD4 + T-cell dynamics in people living with HIV on long-term cART. EBioMedicine 2021; 66:103306. [PMID: 33839064 PMCID: PMC8105504 DOI: 10.1016/j.ebiom.2021.103306] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Low-level HIV viremia originating from virus reactivation in HIV reservoirs is often present in cART treated individuals and represents a persisting source of immune stimulation associated with sub-optimal recovery of CD4+ T cells. The HIV-1 Tat protein is released in the extracellular milieu and activates immune cells and latent HIV, leading to virus production and release. However, the relation of anti-Tat immunity with residual viremia, persistent immune activation and CD4+ T-cell dynamics has not yet been defined. METHODS Volunteers enrolled in a 3-year longitudinal observational study were stratified by residual viremia, Tat serostatus and frequency of anti-Tat cellular immune responses. The impact of anti-Tat immunity on low-level viremia, persistent immune activation and CD4+ T-cell recovery was investigated by test for partitions, longitudinal regression analysis for repeated measures and generalized estimating equations. FINDINGS Anti-Tat immunity is significantly associated with higher nadir CD4+ T-cell numbers, control of low-level viremia and long-lasting CD4+ T-cell recovery, but not with decreased immune activation. In adjusted analysis, the extent of CD4+ T-cell restoration reflects the interplay among Tat immunity, residual viremia and immunological determinants including CD8+ T cells and B cells. Anti-Env immunity was not related to CD4+ T-cell recovery. INTERPRETATION Therapeutic approaches aiming at reinforcing anti-Tat immunity should be investigated to improve immune reconstitution in people living with HIV on long-term cART. TRIAL REGISTRATION ISS OBS T-002 ClinicalTrials.gov identifier: NCT01024556 FUNDING: Italian Ministry of Health, special project on the Development of a vaccine against HIV based on the Tat protein and Ricerca Corrente 2019/2020.
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Affiliation(s)
- Antonella Tripiciano
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Orietta Picconi
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Sonia Moretti
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Cecilia Sgadari
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Vittorio Francavilla
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Angela Arancio
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Giovanni Paniccia
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Massimo Campagna
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | | | - Laura Sighinolfi
- Unit of Infectious Diseases, University Hospital of Ferrara, Ferrara, Italy
| | - Alessandra Latini
- Unit of Dermatology and Sexually Transmitted Diseases, San Gallicano Institute - Istituti Fisioterapici Ospitalieri (IFO) IRCCS, Rome, Italy
| | - Vito S Mercurio
- Department of Infectious Diseases, S. Maria Goretti Hospital, Latina, Italy
| | - Massimo Di Pietro
- Unit of Infectious Diseases, S.M. Annunziata Hospital, Florence, Italy
| | - Francesco Castelli
- University Division of Infectious and Tropical Diseases, University of Brescia and ASST Spedali Civili, Brescia, Italy
| | - Annalisa Saracino
- Division of Infectious Diseases, Policlinic Hospital, University of Bari, Bari, Italy
| | - Cristina Mussini
- Division of Infectious Diseases, University Policlinic of Modena, Modena, Italy
| | - Giovanni Di Perri
- Clinic of Infectious Diseases, Amedeo di Savoia University Hospital, Turin, Italy
| | - Massimo Galli
- Institute of Tropical and Infectious Diseases, L. Sacco University Hospital, Milan, Italy
| | - Silvia Nozza
- Division of Infectious Diseases, S. Raffaele University Hospital IRCCS, Milan, Italy
| | - Fabrizio Ensoli
- Pathology and Microbiology, San Gallicano Institute - (IFO) IRCCS, Rome, Italy
| | - Paolo Monini
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy
| | - Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome 00161, Italy.
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HIV-1 Tat Protein Enters Dysfunctional Endothelial Cells via Integrins and Renders Them Permissive to Virus Replication. Int J Mol Sci 2020; 22:ijms22010317. [PMID: 33396807 PMCID: PMC7796023 DOI: 10.3390/ijms22010317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/21/2020] [Accepted: 12/26/2020] [Indexed: 12/21/2022] Open
Abstract
Previous work has shown that the Tat protein of Human Immunodeficiency Virus (HIV)-1 is released by acutely infected cells in a biologically active form and enters dendritic cells upon the binding of its arginine-glycine-aspartic acid (RGD) domain to the α5β1, αvβ3, and αvβ5 integrins. The up-regulation/activation of these integrins occurs in endothelial cells exposed to inflammatory cytokines that are increased in HIV-infected individuals, leading to endothelial cell dysfunction. Here, we show that inflammatory cytokine-activated endothelial cells selectively bind and rapidly take up nano-micromolar concentrations of Tat, as determined by flow cytometry. Protein oxidation and low temperatures reduce Tat entry, suggesting a conformation- and energy-dependent process. Consistently, Tat entry is competed out by RGD-Tat peptides or integrin natural ligands, and it is blocked by anti-α5β1, -αvβ3, and -αvβ5 antibodies. Moreover, modelling–docking calculations identify a low-energy Tat-αvβ3 integrin complex in which Tat makes contacts with both the αv and β3 chains. It is noteworthy that internalized Tat induces HIV replication in inflammatory cytokine-treated, but not untreated, endothelial cells. Thus, endothelial cell dysfunction driven by inflammatory cytokines renders the vascular system a target of Tat, which makes endothelial cells permissive to HIV replication, adding a further layer of complexity to functionally cure and/or eradicate HIV infection.
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The Tat Protein of HIV-1 Prevents the Loss of HSV-Specific Memory Adaptive Responses and Favors the Control of Viral Reactivation. Vaccines (Basel) 2020; 8:vaccines8020274. [PMID: 32512757 PMCID: PMC7349931 DOI: 10.3390/vaccines8020274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/27/2020] [Accepted: 06/01/2020] [Indexed: 02/07/2023] Open
Abstract
The development of therapeutic strategies to control the reactivation of the Herpes Simplex Virus (HSV) is an unaddressed priority. In this study, we evaluated whether Tat, a HIV-1 protein displaying adjuvant functions, could improve previously established HSV-specific memory responses and prevent viral reactivation. To this aim, mice were infected with non-lethal doses of HSV-1 and, 44 days later, injected or not with Tat. Mice were then monitored to check their health status and measure memory HSV-specific cellular and humoral responses. The appearance of symptoms associated with HSV-reactivation was observed at significantly higher frequencies in the control group than in the Tat-treated mice. In addition, the control animals experienced a time-dependent decrease in HSV-specific Immunoglobulin G (IgG), while the Tat-treated mice maintained antibody titers over time. IgG levels were directly correlated with the number of HSV-specific CD8+ T cells, suggesting an effect of Tat on both arms of the adaptive immunity. Consistent with the maintenance of HSV-specific immune memory, Tat-treated mice showed a better control of HSV-1 re-infection. Although further studies are necessary to assess whether similar effects are observed in other models, these results indicate that Tat exerts a therapeutic effect against latent HSV-1 infection and re-infection by favoring the maintenance of adaptive immunity.
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Alipour S, Mahdavi A. Boosting Tat DNA vaccine with Tat protein stimulates strong cellular and humoral immune responses in mice. Biotechnol Lett 2020; 42:505-517. [PMID: 31974645 DOI: 10.1007/s10529-020-02801-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 12/09/2019] [Indexed: 12/18/2022]
Abstract
The aim of the present study was to evaluate the efficacy of a novel DNA priming-protein boosting regimen in simultaneous enhancing humoral and cellular immunogenicity of the HIV-1-Tat-based candidate vaccines in mice. The experimental BALB/c mice were successfully immunized with the HIV-1-Tat DNA vaccine and boosted with the corresponding protein vaccine over a two-week interval and the elicitation of cellular and humoral immune responses were simultaneously assessed. The results showed that the prime-boost immunization has significantly given rise to lymphocyte proliferation and CTL responses, as well as the levels of both IgG and IgG antibodies compared to the other candidate vaccines. The results of the Th polarization also revealed that the Th1: Th2 indexes in the mice vaccinated with the HIV-1 Tat protein, Tat DNA, and the prime-boost vaccines were 1.03, 1.19, and 1.25, respectively. The results suggest that co-administration of the HIV-1-Tat DNA with the corresponding protein may serve as a potential formulation for enhancing of Tat vaccineinduced immunity and has measurable effects on shaping vaccines' induced Th polarization.
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Affiliation(s)
- Samira Alipour
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), P. O. Box 45195-1159, Zanjan, Iran
| | - Atiyeh Mahdavi
- Department of Biological Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), P. O. Box 45195-1159, Zanjan, Iran.
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Moretti S, Cafaro A, Tripiciano A, Picconi O, Buttò S, Ensoli F, Sgadari C, Monini P, Ensoli B. HIV therapeutic vaccines aimed at intensifying combination antiretroviral therapy. Expert Rev Vaccines 2020; 19:71-84. [PMID: 31957513 DOI: 10.1080/14760584.2020.1712199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Introduction: Although successful at suppressing HIV replication, combination antiretroviral therapy (cART) only partially restores immune functions and fails to reduce the latent HIV reservoir, thus requiring novel interventions for its intensification.Areas covered: Here are reviewed therapeutic vaccine candidates that are being developed to this goal. Among them, the Tat vaccine has been shown to promote immune restoration, including CD4+ T-cell recovery in low immunological responders, and to reduce the virus reservoirs well beyond what achieved with long-term suppressive cART.Expert opinion: The authors propose the Tat vaccine as a promising vaccine candidate for cART intensification toward HIV reservoirs depletion, functional cure, and eradication strategies, suggesting that targeting a key protein in the virus life cycle is pivotal to success.
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Affiliation(s)
- Sonia Moretti
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | | | - Orietta Picconi
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Stefano Buttò
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Fabrizio Ensoli
- Pathology and Microbiology, San Gallicano Dermatological Institute IRCCS, Rome, Italy
| | - Cecilia Sgadari
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Paolo Monini
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
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Yuan Y, Zhou C, Yang Q, Ma S, Wang X, Guo X, Ding Y, Tang J, Zeng Y, Li D. HIV-1 Tat protein inhibits the hematopoietic support function of human bone marrow mesenchymal stem cells. Virus Res 2019; 273:197756. [PMID: 31521762 DOI: 10.1016/j.virusres.2019.197756] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/11/2019] [Accepted: 09/11/2019] [Indexed: 12/21/2022]
Abstract
Most HIV-1-infected patients experience hematopoiesis suppression complications. Bone marrow mesenchymal stem cells (BMSCs) are involved in regulation of hematopoietic homeostasis, so we investigated the role of Tat, a protein released by infected cells in bone marrow and impacted differentiation potential of mesenchymal stem cells, in the BMSC hematopoietic support function. BMSCs were treated with HIV-1 Tat protein (BMSCTat-p), transfected with HIV-1 Tat mRNA (BMSCTat-m) or treated with solvent (PBS) (BMSCcon) for 20 days. Then, the hematopoietic support function of BMSCTat-p, BMSCTat-m and BMSCcon was analyzed via ex vivo expansion of hematopoietic stem cells (HSCs) grown on the BMSCs and via in vivo cotransplantation of HSCs and BMSCs. In addition, the hematopoiesis-supporting gene expression patterns of BMSCTat-p, BMSCTat-m and BMSCcon were compared. The results showed that BMSCTat-p and BMSCTat-m displayed reduced expansion, a decline in the number of colony forming units (CFUs) and a decreased proportion of the primitive subpopulation of hematopoietic stem cells under coculture conditions compared with BMSCcon. The ability of BMSCTat-p to support hematopoietic recovery was also impaired, which was further confirmed by the patterns in gene expression analysis. In conclusion, Tat treatment reduced the function of BMSCs in hematopoietic support, likely by downregulating the expression of a series of hematopoietic cytokines.
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Affiliation(s)
- Yahong Yuan
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China
| | - Chunfang Zhou
- Department of Gastroenterology, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China
| | - Qi Yang
- Department of Spinal Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China
| | - Shinan Ma
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China
| | - Xiaoli Wang
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China
| | - Xingrong Guo
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China
| | - Yan Ding
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China
| | - Junming Tang
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China
| | - Yi Zeng
- College of Life Science and Bioengineering, Beijing University of Technology, Beijing, 100124, China
| | - Dongsheng Li
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, 32 S. Renmin Rd., Shiyan, Hubei, 442000, China.
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Cafaro A, Tripiciano A, Picconi O, Sgadari C, Moretti S, Buttò S, Monini P, Ensoli B. Anti-Tat Immunity in HIV-1 Infection: Effects of Naturally Occurring and Vaccine-Induced Antibodies Against Tat on the Course of the Disease. Vaccines (Basel) 2019; 7:vaccines7030099. [PMID: 31454973 PMCID: PMC6789840 DOI: 10.3390/vaccines7030099] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/08/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023] Open
Abstract
HIV-1 Tat is an essential protein in the virus life cycle, which is required for virus gene expression and replication. Most Tat that is produced during infection is released extracellularly and it plays a key role in HIV pathogenesis, including residual disease upon combination antiretroviral therapy (cART). Here, we review epidemiological and experimental evidence showing that antibodies against HIV-1 Tat, infrequently occurring in natural infection, play a protective role against disease progression, and that vaccine targeting Tat can intensify cART. In fact, Tat vaccination of subjects on suppressive cART in Italy and South Africa promoted immune restoration, including CD4+ T-cell increase in low immunological responders, and a reduction of proviral DNA even after six years of cART, when both CD4+ T-cell gain and DNA decay have reached a plateau. Of note, DNA decay was predicted by the neutralization of Tat-mediated entry of Env into dendritic cells by anti-Tat antibodies, which were cross-clade binding and neutralizing. Anti-Tat cellular immunity also contributed to the DNA decay. Based on these data, we propose the Tat therapeutic vaccine as a pathogenesis-driven intervention that effectively intensifies cART and it may lead to a functional cure, providing new perspectives and opportunities also for prevention and virus eradication strategies.
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Affiliation(s)
- Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Antonella Tripiciano
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Orietta Picconi
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Cecilia Sgadari
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Sonia Moretti
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Stefano Buttò
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Paolo Monini
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy
| | - Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome 00161, Italy.
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11
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Sgadari C, Monini P, Tripiciano A, Picconi O, Casabianca A, Orlandi C, Moretti S, Francavilla V, Arancio A, Paniccia G, Campagna M, Bellino S, Meschiari M, Nozza S, Sighinolfi L, Latini A, Muscatello A, Saracino A, Di Pietro M, Galli M, Cafaro A, Magnani M, Ensoli F, Ensoli B. Continued Decay of HIV Proviral DNA Upon Vaccination With HIV-1 Tat of Subjects on Long-Term ART: An 8-Year Follow-Up Study. Front Immunol 2019; 10:233. [PMID: 30815001 PMCID: PMC6381398 DOI: 10.3389/fimmu.2019.00233] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/28/2019] [Indexed: 02/02/2023] Open
Abstract
Introduction: Tat, a key HIV virulence protein, has been targeted for the development of a therapeutic vaccine aimed at cART intensification. Results from phase II clinical trials in Italy (ISS T-002) and South Africa (ISS T-003) indicated that Tat vaccination promotes increases of CD4+ T-cells and return to immune homeostasis while reducing the virus reservoir in chronically cART-treated patients. Here we present data of 92 vaccinees (59% of total vaccinees) enrolled in the ISS T-002 8-year extended follow-up study (ISS T-002 EF-UP, ClinicalTrials.gov NCT02118168). Results: Anti-Tat antibodies (Abs) induced upon vaccination persisted for the entire follow-up in 34/92 (37%) vaccinees, particularly when all 3 Ab classes (A/G/M) were present (66% of vaccinees), as most frequently observed with Tat 30 μg regimens. CD4+ T cells increased above study-entry levels reaching a stable plateau at year 5 post-vaccination, with the highest increase (165 cells/μL) in the Tat 30 μg, 3 × regimen. CD4+ T-cell increase occurred even in subjects with CD4+ nadir ≤ 250 cells/uL and in poor immunological responders and was associated with a concomitant increase of the CD4+/CD8+ T-cell ratio, a prognostic marker of morbidity/mortality inversely related to HIV reservoir size. Proviral DNA load decreased over time, with a half-life of 2 years and an estimated 90% reduction at year 8 in the Tat 30 μg, 3 × group. In multivariate analysis the kinetic and amplitude of both CD4+ T-cell increase and proviral DNA reduction were fastest and highest in subjects with all 3 anti-Tat Ab classes and in the 30 μg, 3 × group, irrespective of drug regimens (NNRTI/NRTI vs. PI). HIV proviral DNA changes from baseline were inversely related to CD4+/CD8+ T-cell ratio and CD4+ T-cell changes, and directly related to the changes of CD8+ T cells. Further, HIV DNA decay kinetics were inversely related to the frequency and levels of intermittent viremia. Finally, Tat vaccination was similarly effective irrespective of the individual immunological status or HIV reservoir size at study entry. Conclusions: Tat immunization induces progressive immune restoration and reduction of virus reservoirs above levels reached with long-term cART, and may represent an optimal vaccine candidate for cART intensification toward HIV reservoirs depletion, functional cure, and eradication strategies.
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Affiliation(s)
- Cecilia Sgadari
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Paolo Monini
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | | | - Orietta Picconi
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Anna Casabianca
- Department of Biomolecular Science, University of Urbino, Urbino, Italy
| | - Chiara Orlandi
- Department of Biomolecular Science, University of Urbino, Urbino, Italy
| | - Sonia Moretti
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | | | - Angela Arancio
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Giovanni Paniccia
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Massimo Campagna
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Stefania Bellino
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Marianna Meschiari
- Division of Infectious Diseases, University Policlinic of Modena, Modena, Italy
| | - Silvia Nozza
- Division of Infectious Diseases, San Raffaele Hospital, Milan, Italy
| | - Laura Sighinolfi
- Unit of Infectious Diseases, University Hospital of Ferrara, Ferrara, Italy
| | - Alessandra Latini
- Unit of Dermatology and Sexually Transmitted Diseases, San Gallicano Dermatological Institute IRCCS, Rome, Italy
| | - Antonio Muscatello
- Infectious Diseases Unit, IRCCS Ca' Granda Ospedale Maggiore Policlinico Foundation, University of Milan, Milan, Italy
| | - Annalisa Saracino
- Division of Infectious Diseases, University of Bari, Policlinic Hospital, Bari, Italy
| | - Massimo Di Pietro
- Unit of Infectious Diseases, Santa Maria Annunziata Hospital, Florence, Italy
| | - Massimo Galli
- Institute of Tropical and Infectious Diseases, L. Sacco Hospital, University of Milan, Milan, Italy
| | - Aurelio Cafaro
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Science, University of Urbino, Urbino, Italy
| | - Fabrizio Ensoli
- Pathology and Microbiology, San Gallicano Dermatological Institute IRCCS, Rome, Italy
| | - Barbara Ensoli
- National HIV/AIDS Research Center, Istituto Superiore di Sanità, Rome, Italy
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12
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Dong H, Jing W, Yingru X, Wenyang W, Ru C, Shengfa N, Congjing X, Jingjing D, Wan W, Jiang H, Rongbo Z. Enhanced anti-tuberculosis immunity by a TAT-Ag85B protein vaccine in a murine tuberculosis model. Pathog Glob Health 2016; 109:363-8. [PMID: 26924346 DOI: 10.1080/20477724.2015.1111658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
BACKGROUND The development of more effective anti-tuberculosis vaccines would contribute to the control of the global problem of infection with Mycobacterium tuberculosis (MTB). Recently, increasing evidences showed that HIV-Tat protein transduction domain is implicated in promotion of vaccines by inducing cellular immuno-response. However, it is rare known about the role of TAT in vaccines against MTB. METHODS In this study, we expressed recombinant protein-fused Ag85B with TAT (TAT-Ag85B) which was used as a vaccine to inoculate mice infected with MTB. RESULTS As s result, both IgG2a in serum and IFN-γ or TNFα produced by spleen cells were all increased significantly in the mice inoculated by TAT-Ag85B. Furthermore, consistently, TAT-Ag85B inoculation significantly reduced MTB loads both in lung and spleen. CONCLUSIONS These findings demonstrate that a novel protein vaccine of TAT-Ag85B enhances immune response both in humoral and cellular immunity, and contributes to protective efficacy against MTB.
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Affiliation(s)
- Hu Dong
- 1 Department of Medical Immunology, Medical School, Anhui University of Science and Technology , Huainan, China
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13
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HIV-1 Tat Recruits HDM2 E3 Ligase To Target IRF-1 for Ubiquitination and Proteasomal Degradation. mBio 2016; 7:mBio.01528-16. [PMID: 27795392 PMCID: PMC5082900 DOI: 10.1128/mbio.01528-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In addition to its ability to regulate HIV-1 promoter activation, the viral transactivator Tat also functions as a determinant of pathogenesis and disease progression by directly and indirectly modulating the host anti-HIV response, largely through the capacity of Tat to interact with and modulate the activities of multiple host proteins. We previously demonstrated that Tat modulated both viral and host transcriptional machinery by interacting with the cellular transcription factor interferon regulatory factor 1 (IRF-1). In the present study, we investigated the mechanistic basis and functional significance of Tat−IRF-1 interaction and demonstrate that Tat dramatically decreased IRF-1 protein stability. To accomplish this, Tat exploited the cellular HDM2 (human double minute 2 protein) ubiquitin ligase to accelerate IRF-1 proteasome-mediated degradation, resulting in a quenching of IRF-1 transcriptional activity during HIV-1 infection. These data identify IRF-1 as a new target of Tat-induced modulation of the cellular protein machinery and reveal a new strategy developed by HIV-1 to evade host immune responses. Current therapies have dramatically reduced morbidity and mortality associated with HIV infection and have converted infection from a fatal pathology to a chronic disease that is manageable via antiretroviral therapy. Nevertheless, HIV-1 infection remains a challenge, and the identification of useful cellular targets for therapeutic intervention remains a major goal. The cellular transcription factor IRF-1 impacts various physiological functions, including the immune response to viral infection. In this study, we have identified a unique mechanism by which HIV-1 evades IRF-1-mediated host immune responses and show that the viral protein Tat accelerates IRF-1 proteasome-mediated degradation and inactivates IRF-1 function. Restoration of IRF-1 functionality may thus be regarded as a potential strategy to reinstate both a direct antiviral response and a more broadly acting immune regulatory circuit.
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14
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Cafaro A, Piccaro G, Altavilla G, Gigantino V, Matarese G, Olivieri E, Ferrantelli F, Ensoli B, Palma C. HIV-1 Tat protein vaccination in mice infected with Mycobacterium tuberculosis is safe, immunogenic and reduces bacterial lung pathology. BMC Infect Dis 2016; 16:442. [PMID: 27549342 PMCID: PMC4994248 DOI: 10.1186/s12879-016-1724-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 07/19/2016] [Indexed: 01/01/2023] Open
Abstract
Background The therapeutic HIV-1 Tat protein vaccine is in advanced clinical development. Tuberculosis, the main AIDS co-infection, is highly endemic in areas where AIDS prevention through vaccination is needed. However, safety and immunogenicity of Tat vaccination in the course of Mycobacterium tuberculosis (Mtb) infection is still unknown and it prevents the possibility to administer the vaccine to Mtb-infected individuals. We addressed the interplay and effects of Tat vaccination on Mtb infection in immunocompetent mice. Methods C57BL/6 mice were vaccinated or not with Bacillus Calmette-Guerin (BCG), the current tuberculosis vaccine, and after 5 weeks were infected with Mtb by intravenous route. The Tat protein was injected intradermally at 1, 2 and 4 weeks after Mtb challenge. Eight weeks after Mtb infection, all mice were sacrificed, and both the degree of pathology and immune responses to Mtb and Tat were evaluated. As additional control, some mice were either vaccinated or not with BCG, were not challenged with Mtb, but received the Tat protein. Statistical significances were evaluated by one-way or two-way ANOVA and Tukey’s multiple comparisons post-test. Results In the lungs of Mtb-infected mice, Tat-vaccine did not favour Mtb replication and indeed reduced both area of cellular infiltration and protein levels of Interferon-γ, Chemokine (C-C motif) ligand-4 and Interleukin-1β, pathological events triggered by Mtb-infection. Moreover, the protection against Mtb infection conferred by BCG remained good after Tat protein treatment. In spleen cells of Mtb-infected mice, Tat vaccination enhanced Mtb-specific Interferon-γ and Interleukin-17 responses, which may have a protective role. Of note, Mtb infection reduced, but did not suppress, the development of anti-Tat antibodies, required for Tat vaccine efficacy and the titer of anti-Tat IgG was potentiated by BCG vaccination in Mtb-free mice. In general, Tat treatment was well tolerated in both Mtb-infected and Mtb-free mice. Conclusions Tat protein vaccine, administered in Mtb-infected mice with a protocol resembling that used in the clinical trials, was safe, immunogenic, limited the lung Mtb-associated immunopathology and did not abrogate the protective efficacy of BCG. These data provide preliminary evidence for a safe use of Tat vaccine in people vaccinated with BCG and/or suffering from tuberculosis.
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Affiliation(s)
- Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena, Rome, 299 00161, Italy.
| | - Giovanni Piccaro
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, Rome, 299 00161, Italy
| | | | - Vincenzo Gigantino
- Istituto di Endocrinologia e Oncologia Sperimentale, Consiglio Nazionale delle Ricerche (IEOS-CNR) c/o Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy.,Dipartimento di Patologia Fondazione G. Pascale IRCCS, Naples, Italy
| | - Giuseppe Matarese
- Dipartimento di Medicina e Chirurgia, Università di Salerno, Salerno, Italy.,MultiMedica IRCCS, Milan, Italy
| | - Erika Olivieri
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena, Rome, 299 00161, Italy
| | - Flavia Ferrantelli
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena, Rome, 299 00161, Italy
| | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena, Rome, 299 00161, Italy
| | - Carla Palma
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Viale Regina Elena, Rome, 299 00161, Italy.
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15
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Ensoli B, Nchabeleng M, Ensoli F, Tripiciano A, Bellino S, Picconi O, Sgadari C, Longo O, Tavoschi L, Joffe D, Cafaro A, Francavilla V, Moretti S, Pavone Cossut MR, Collacchi B, Arancio A, Paniccia G, Casabianca A, Magnani M, Buttò S, Levendal E, Ndimande JV, Asia B, Pillay Y, Garaci E, Monini P. HIV-Tat immunization induces cross-clade neutralizing antibodies and CD4(+) T cell increases in antiretroviral-treated South African volunteers: a randomized phase II clinical trial. Retrovirology 2016; 13:34. [PMID: 27277839 PMCID: PMC4899930 DOI: 10.1186/s12977-016-0261-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/14/2016] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Although combined antiretroviral therapy (cART) has saved millions of lives, it is incapable of full immune reconstitution and virus eradication. The transactivator of transcription (Tat) protein is a key human immunodeficiency virus (HIV) virulence factor required for virus replication and transmission. Tat is expressed and released extracellularly by infected cells also under cART and in this form induces immune dysregulation, and promotes virus reactivation, entry and spreading. Of note, anti-Tat antibodies are rare in natural infection and, when present, correlate with asymptomatic state and reduced disease progression. This suggested that induction of anti-Tat antibodies represents a pathogenesis-driven intervention to block progression and to intensify cART. Indeed Tat-based vaccination was safe, immunogenic and capable of immune restoration in an open-label, randomized phase II clinical trial conducted in 168 cART-treated volunteers in Italy. To assess whether B-clade Tat immunization would be effective also in patients with different genetic background and infecting virus, a phase II trial was conducted in South Africa. METHODS The ISS T-003 was a 48-week randomised, double-blinded, placebo-controlled trial to evaluate immunogenicity (primary endpoint) and safety (secondary endpoint) of B-clade Tat (30 μg) given intradermally, three times at 4-week intervals, in 200 HIV-infected adults on effective cART (randomised 1:1) with CD4(+) T-cell counts ≥200 cells/µL. Study outcomes also included cross-clade anti-Tat antibodies, neutralization, CD4(+) T-cell counts and therapy compliance. RESULTS Immunization was safe and well-tolerated and induced durable, high titers anti-Tat B-clade antibodies in 97 % vaccinees. Anti-Tat antibodies were cross-clade (all vaccinees tested) and neutralized Tat-mediated entry of oligomeric B-clade and C-clade envelope in dendritic cells (24 participants tested). Anti-Tat antibody titers correlated positively with neutralization. Tat vaccination increased CD4(+) T-cell numbers (all participants tested), particularly when baseline levels were still low after years of therapy, and this had a positive correlation with HIV neutralization. Finally, in cART non-compliant patients (24 participants), vaccination contained viral load rebound and maintained CD4(+) T-cell numbers over study entry levels as compared to placebo. CONCLUSIONS The data indicate that Tat vaccination can restore the immune system and induces cross-clade neutralizing anti-Tat antibodies in patients with different genetic backgrounds and infecting viruses, supporting the conduct of phase III studies in South Africa. Trial registration ClinicalTrials.gov NCT01513135, 01/23/2012.
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Affiliation(s)
- Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
| | | | - Fabrizio Ensoli
- Laboratory of Clinical Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy
| | - Antonella Tripiciano
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.,Laboratory of Clinical Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy
| | - Stefania Bellino
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.,National Center for Epidemiology, Surveillance and Health Promotion, Istituto Superiore di Sanità, Rome, Italy
| | - Orietta Picconi
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Cecilia Sgadari
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Olimpia Longo
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.,Italian Medicines Agency, Rome, Italy
| | - Lara Tavoschi
- Head Office, National AIDS Center, Istituto Superiore di Sanità, Cape Town, South Africa.,European Center for Disease Prevention and Control, Stockholm, Sweden
| | - Daniel Joffe
- Head Office, National AIDS Center, Istituto Superiore di Sanità, Cape Town, South Africa
| | - Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Vittorio Francavilla
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.,Laboratory of Clinical Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy
| | - Sonia Moretti
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | | | | | - Angela Arancio
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.,Laboratory of Clinical Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy
| | - Giovanni Paniccia
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.,Laboratory of Clinical Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy
| | - Anna Casabianca
- Department of Biomolecular Science, University of Urbino, Urbino, Italy
| | - Mauro Magnani
- Department of Biomolecular Science, University of Urbino, Urbino, Italy
| | - Stefano Buttò
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Elise Levendal
- South African Medical Research Council, Cape Town, South Africa.,Health Systems Trust, Cape Town, South Africa
| | | | - Bennett Asia
- National Department of Health, Pretoria, South Africa
| | - Yogan Pillay
- National Department of Health, Pretoria, South Africa
| | - Enrico Garaci
- Istituto Superiore di Sanità, Rome, Italy.,University of Tor Vergata, Rome, Italy
| | - Paolo Monini
- Head Office, National AIDS Center, Istituto Superiore di Sanità, Cape Town, South Africa
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16
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Palmer CS, Cherry CL, Sada-Ovalle I, Singh A, Crowe SM. Glucose Metabolism in T Cells and Monocytes: New Perspectives in HIV Pathogenesis. EBioMedicine 2016; 6:31-41. [PMID: 27211546 PMCID: PMC4856752 DOI: 10.1016/j.ebiom.2016.02.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 02/06/2023] Open
Abstract
Activation of the immune system occurs in response to the recognition of foreign antigens and receipt of optimal stimulatory signals by immune cells, a process that requires energy. Energy is also needed to support cellular growth, differentiation, proliferation, and effector functions of immune cells. In HIV-infected individuals, persistent viral replication, together with inflammatory stimuli contributes to chronic immune activation and oxidative stress. These conditions remain even in subjects with sustained virologic suppression on antiretroviral therapy. Here we highlight recent studies demonstrating the importance of metabolic pathways, particularly those involving glucose metabolism, in differentiation and maintenance of the activation states of T cells and monocytes. We also discuss how changes in the metabolic status of these cells may contribute to ongoing immune activation and inflammation in HIV- infected persons and how this may contribute to disease progression, establishment and persistence of the HIV reservoir, and the development of co-morbidities. We provide evidence that other viruses such as Epstein-Barr and Flu virus also disrupt the metabolic machinery of their host cells. Finally, we discuss how redox signaling mediated by oxidative stress may regulate metabolic responses in T cells and monocytes during HIV infection.
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Affiliation(s)
- Clovis S Palmer
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia; Department of Infectious Diseases, Monash University, Melbourne, Australia.
| | - Catherine L Cherry
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia; Department of Infectious Diseases, Monash University, Melbourne, Australia; Infectious Diseases Department, The Alfred Hospital, Melbourne, Australia; School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
| | - Isabel Sada-Ovalle
- Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas, Mexico
| | - Amit Singh
- Department of Microbiology and Cell Biology, Centre for Infectious Disease and Research (CIDR), Indian Institute of Science, India
| | - Suzanne M Crowe
- Centre for Biomedical Research, Burnet Institute, Melbourne, Australia; Department of Infectious Diseases, Monash University, Melbourne, Australia; Infectious Diseases Department, The Alfred Hospital, Melbourne, Australia
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17
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Finessi V, Nicoli F, Gallerani E, Sforza F, Sicurella M, Cafaro A, Caputo A, Ensoli B, Gavioli R. Effects of different routes of administration on the immunogenicity of the Tat protein and a Tat-derived peptide. Hum Vaccin Immunother 2016; 11:1489-93. [PMID: 25875962 DOI: 10.1080/21645515.2015.1016676] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The use of the Tat protein of HIV in vaccines against AIDS showed promising results in primate and human studies. To characterize the impact of the administration route on the induction of humoral responses at systemic and mucosal levels, we compared intradermal, intramuscular and mucosal immunizations with Tat and a Tat-derived peptide. Mice were immunized with the Tat protein by different routes and the titer and isotype of anti-Tat antibodies were assessed in serum and mucosal lavages. Intramuscular and intradermal administrations showed comparable immunogenicity, while the mucosal administration was unable to induce IgM in serum and IgG at mucosal sites but showed superior immunogenicity in terms of IgA induction. Anti-Tat antibodies were also obtained upon vaccination with the immunodominant Tat 1-20 peptide which was, however, less immunogenic than the whole Tat protein.
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Affiliation(s)
- Valentina Finessi
- a Department of Life Sciences and Biotechnology; University of Ferrara ; Ferrara , Italy
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18
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Zhang W, Luo X, Zhang F, Zhu Y, Yang B, Hou M, Xu Z, Yu C, Chen Y, Chen L, Ji M. SjTat-TPI facilitates adaptive T-cell responses and reduces hepatic pathology during Schistosoma japonicum infection in BALB/c mice. Parasit Vectors 2015; 8:664. [PMID: 26714844 PMCID: PMC4696208 DOI: 10.1186/s13071-015-1275-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/18/2015] [Indexed: 12/18/2022] Open
Abstract
Background Schistosomiasis is a kind of parasitic zoonoses which causes serious damage to public health and social development. China is one of the countries most affected by Schistosoma japonicum and an effective vaccine is still needed. In this study, we adopted Tat-mediated protein transduction technology to investigate the impact of different antigen presented approaches on host’s immune response and the potential protection against Schistosoma japonicum infection. Results We successfully constructed the recombinant S. japonicum triosephosphate isomerase, Tat-TPI, as a vaccine candidate. Whether injected with Tat-TPI in foot pad or vaccinated with Tat-TPI in the back subcutaneously for three times, the draining popliteal lymph nodes and spleen both developed a stronger CD8+T response (Tc1) in mice. Not only that, but it also helped CD4+T cells to produce more IFN-γ than TPI immunisation. In addition, it could boost IgG production, especially IgG1 subclass. Most importantly, Tat-TPI immunisation led to the significant smaller area of a single egg granuloma in the livers as compared with TPI-vaccinated or control groups. However, the anti-infection efficiency induced by Tat-TPI was still restricted. Conclusion This study indicated that immunisation with Tat-fused TPI could contribute to enhance CD4+T-cell response and decrease hepatic egg granulomatous area after S. japonicum infection though it did not achieve our expected protection against Schistosoma japonicum infection. The optimal vaccine strategy warrants further research.
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Affiliation(s)
- Wenyue Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| | - Xiaofeng Luo
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| | - Fan Zhang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| | - Yuxiao Zhu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| | - Bingya Yang
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China. .,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, 210029, China.
| | - Min Hou
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| | - Zhipeng Xu
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China. .,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, 210029, China.
| | - Chuanxin Yu
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, 214064, China.
| | - Yingying Chen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China.
| | - Lin Chen
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China. .,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, 210029, China.
| | - Minjun Ji
- Department of Pathogen Biology, Nanjing Medical University, Nanjing, Jiangsu, 210029, China. .,Jiangsu Province Key Laboratory of Modern Pathogen Biology, Nanjing, Jiangsu, 210029, China.
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19
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Cafaro A, Tripiciano A, Sgadari C, Bellino S, Picconi O, Longo O, Francavilla V, Buttò S, Titti F, Monini P, Ensoli F, Ensoli B. Development of a novel AIDS vaccine: the HIV-1 transactivator of transcription protein vaccine. Expert Opin Biol Ther 2015; 15 Suppl 1:S13-29. [PMID: 26096836 DOI: 10.1517/14712598.2015.1021328] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Classical approaches aimed at targeting the HIV-1 envelope as well as other structural viral proteins have largely failed. The HIV-1 transactivator of transcription (Tat) is a key HIV virulence factor, which plays pivotal roles in virus gene expression, replication, transmission and disease progression. Notably, anti-Tat Abs are uncommon in natural infection and, when present, correlate with the asymptomatic state and lead to lower or no disease progression. Hence, targeting Tat represents a pathogenesis-driven intervention. AREAS COVERED Here, we review the rationale and the translational development of a therapeutic vaccine targeting the Tat protein. Preclinical and Phase I studies, Phase II trials with Tat in anti-Tat Ab-negative, virologically suppressed highly active antiretroviral therapy-treated subjects in Italy and South Africa were conducted. The results indicate that Tat-induced immune responses are necessary to restore immune homeostasis, to block the replenishment and to reduce the size of the viral reservoir. Additionally, they may help in establishing key parameters for highly active antiretroviral therapy intensification and a functional cure. EXPERT OPINION We propose the therapeutic setting as the most feasible to speed up the testing and comparison of preventative vaccine candidates, as the distinction lies in the use of the vaccine in uninfected versus infected subjects and not in the vaccine formulation.
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Affiliation(s)
- Aurelio Cafaro
- Istituto Superiore di Sanità, National AIDS Center , Rome , Italy
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20
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Ensoli F, Cafaro A, Casabianca A, Tripiciano A, Bellino S, Longo O, Francavilla V, Picconi O, Sgadari C, Moretti S, Cossut MRP, Arancio A, Orlandi C, Sernicola L, Maggiorella MT, Paniccia G, Mussini C, Lazzarin A, Sighinolfi L, Palamara G, Gori A, Angarano G, Di Pietro M, Galli M, Mercurio VS, Castelli F, Di Perri G, Monini P, Magnani M, Garaci E, Ensoli B. HIV-1 Tat immunization restores immune homeostasis and attacks the HAART-resistant blood HIV DNA: results of a randomized phase II exploratory clinical trial. Retrovirology 2015; 12:33. [PMID: 25924841 PMCID: PMC4414440 DOI: 10.1186/s12977-015-0151-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 02/11/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The phase II multicenter, randomized, open label, therapeutic trial (ISS T-002, Clinicaltrials.gov NCT00751595) was aimed at evaluating the immunogenicity and the safety of the biologically active HIV-1 Tat protein administered at 7.5 or 30 μg, given 3 or 5 times monthly, and at exploring immunological and virological disease biomarkers. The study duration was 48 weeks, however, vaccinees were followed until the last enrolled subject reached the 48 weeks. Reported are final data up to 144 weeks of follow-up. The ISS T-002 trial was conducted in 11 clinical centers in Italy on 168 HIV positive subjects under Highly Active Antiretroviral Therapy (HAART), anti-Tat Antibody (Ab) negative at baseline, with plasma viremia <50 copies/mL in the last 6 months prior to enrollment, and CD4(+) T-cell number ≥200 cells/μL. Subjects from a parallel observational study (ISS OBS T-002, Clinicaltrials.gov NCT0102455) enrolled at the same clinical sites with the same criteria constituted an external reference group to explore biomarkers of disease. RESULTS The vaccine was safe and well tolerated and induced anti-Tat Abs in most patients (79%), with the highest frequency and durability in the Tat 30 μg groups (89%) particularly when given 3 times (92%). Vaccination promoted a durable and significant restoration of T, B, natural killer (NK) cells, and CD4(+) and CD8(+) central memory subsets. Moreover, a significant reduction of blood proviral DNA was seen after week 72, particularly under PI-based regimens and with Tat 30 μg given 3 times (30 μg, 3x), reaching a predicted 70% decay after 3 years from vaccination with a half-life of 88 weeks. This decay was significantly associated with anti-Tat IgM and IgG Abs and neutralization of Tat-mediated entry of oligomeric Env in dendritic cells, which predicted HIV-1 DNA decay. Finally, the 30 μg, 3x group was the only one showing significant increases of NK cells and CD38(+)HLA-DR(+)/CD8(+) T cells, a phenotype associated with increased killing activity in elite controllers. CONCLUSIONS Anti-Tat immune responses are needed to restore immune homeostasis and effective anti-viral responses capable of attacking the virus reservoir. Thus, Tat immunization represents a promising pathogenesis-driven intervention to intensify HAART efficacy.
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Affiliation(s)
- Fabrizio Ensoli
- Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy.
| | - Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Anna Casabianca
- Department of Biomolecular Science, University of Urbino, Urbino, Italy.
| | - Antonella Tripiciano
- Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy. .,National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Stefania Bellino
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Olimpia Longo
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Vittorio Francavilla
- Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy. .,National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Orietta Picconi
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Cecilia Sgadari
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Sonia Moretti
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Maria R Pavone Cossut
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Angela Arancio
- Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy. .,National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Chiara Orlandi
- Department of Biomolecular Science, University of Urbino, Urbino, Italy.
| | - Leonardo Sernicola
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Maria T Maggiorella
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Giovanni Paniccia
- Pathology and Microbiology, San Gallicano Institute, Istituti Fisioterapici Ospitalieri, Rome, Italy. .,National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Cristina Mussini
- Division of Infectious Diseases, University Policlinic of Modena, Modena, Italy.
| | - Adriano Lazzarin
- Division of Infectious Diseases, S. Raffaele Hospital, Milan, Italy.
| | - Laura Sighinolfi
- Unit of Infectious Diseases, University Hospital of Ferrara, Ferrara, Italy.
| | - Guido Palamara
- Department of Infectious Dermatology, San Gallicano Hospital, Rome, Italy.
| | - Andrea Gori
- Division of Infectious Diseases, San Gerardo Hospital, Monza, Italy.
| | - Gioacchino Angarano
- Division of Infectious Diseases, University of Bari, Policlinic Hospital, Bari, Italy.
| | - Massimo Di Pietro
- Unit of Infectious Diseases, S.M. Annunziata Hospital, Florence, Italy.
| | - Massimo Galli
- Institute of Tropical and Infectious Diseases, L. Sacco Hospital, University of Milan, Milan, Italy.
| | - Vito S Mercurio
- Department of Infectious Diseases, S. Maria Goretti Hospital, Latina, Italy.
| | - Francesco Castelli
- Division of Tropical and Infectious Diseases, Spedali Civili, Brescia, Italy.
| | - Giovanni Di Perri
- Clinic of Infectious Diseases, Amedeo di Savoia Hospital, Turin, Italy.
| | - Paolo Monini
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
| | - Mauro Magnani
- Department of Biomolecular Science, University of Urbino, Urbino, Italy.
| | - Enrico Garaci
- Istituto Superiore di Sanità, Rome, Italy, present address University of Tor Vergata, Rome, 00173, Italy.
| | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, 00161, Italy.
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Araínga M, Guo D, Wiederin J, Ciborowski P, McMillan J, Gendelman HE. Opposing regulation of endolysosomal pathways by long-acting nanoformulated antiretroviral therapy and HIV-1 in human macrophages. Retrovirology 2015; 12:5. [PMID: 25608975 PMCID: PMC4307176 DOI: 10.1186/s12977-014-0133-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/19/2014] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Long-acting nanoformulated antiretroviral therapy (nanoART) is designed to improve patient regimen adherence, reduce systemic drug toxicities, and facilitate clearance of human immunodeficiency virus type one (HIV-1) infection. While nanoART establishes drug depots within recycling and late monocyte-macrophage endosomes, whether or not this provides a strategic advantage towards viral elimination has not been elucidated. RESULTS We applied quantitative SWATH-MS proteomics and cell profiling to nanoparticle atazanavir (nanoATV)-treated and HIV-1 infected human monocyte-derived macrophages (MDM). Native ATV and uninfected cells served as controls. Both HIV-1 and nanoATV engaged endolysosomal trafficking for assembly and depot formation, respectively. Notably, the pathways were deregulated in opposing manners by the virus and the nanoATV, likely by viral clearance. Paired-sample z-scores, of the proteomic data sets, showed up- and down- regulation of Rab-linked endolysosomal proteins. NanoART and native ATV treated uninfected cells showed limited effects. The data was confirmed by Western blot. DAVID and KEGG bioinformatics analyses of proteomic data showed relationships between secretory, mobility and phagocytic cell functions and virus and particle trafficking. CONCLUSIONS We posit that modulation of endolysosomal pathways by antiretroviral nanoparticles provides a strategic path to combat HIV infection.
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Affiliation(s)
- Mariluz Araínga
- />Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, Omaha, NE 68198-5880 USA
| | - Dongwei Guo
- />Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, Omaha, NE 68198-5880 USA
- />Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-5880 USA
| | - Jayme Wiederin
- />Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, Omaha, NE 68198-5880 USA
| | - Pawel Ciborowski
- />Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, Omaha, NE 68198-5880 USA
| | - JoEllyn McMillan
- />Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, Omaha, NE 68198-5880 USA
| | - Howard E Gendelman
- />Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, 985880 Nebraska Medical Center, Omaha, NE 68198-5880 USA
- />Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-5880 USA
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Different expression of Blimp-1 in HIV infection may be used to monitor disease progression and provide a clue to reduce immune activation and viral reservoirs. AIDS 2015; 29:133-4. [PMID: 25562499 DOI: 10.1097/qad.0000000000000514] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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23
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Biocompatible anionic polymeric microspheres as priming delivery system for effetive HIV/AIDS Tat-based vaccines. PLoS One 2014; 9:e111360. [PMID: 25356594 PMCID: PMC4214729 DOI: 10.1371/journal.pone.0111360] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 10/01/2014] [Indexed: 11/19/2022] Open
Abstract
Here we describe a prime-boost regimen of vaccination in Macaca fascicularis that combines priming with novel anionic microspheres designed to deliver the biologically active HIV-1 Tat protein and boosting with Tat in Alum. This regimen of immunization modulated the IgG subclass profile and elicited a balanced Th1-Th2 type of humoral and cellular responses. Remarkably, following intravenous challenge with SHIV89.6Pcy243, vaccinees significantly blunted acute viremia, as compared to control monkeys, and this control was associated with significantly lower CD4+ T cell depletion rate during the acute phase of infection and higher ability to resume the CD4+ T cell counts in the post-acute and chronic phases of infection. The long lasting control of viremia was associated with the persistence of high titers anti-Tat antibodies whose profile clearly distinguished vaccinees in controllers and viremics. Controllers, as opposed to vaccinated and viremic cynos, exhibited significantly higher pre-challenge antibody responses to peptides spanning the glutamine-rich and the RGD-integrin-binding regions of Tat. Finally, among vaccinees, titers of anti-Tat IgG1, IgG3 and IgG4 subclasses had a significant association with control of viremia in the acute and post-acute phases of infection. Altogether these findings indicate that the Tat/H1D/Alum regimen of immunization holds promise for next generation vaccines with Tat protein or other proteins for which maintenance of the native conformation and activity are critical for optimal immunogenicity. Our results also provide novel information on the role of anti-Tat responses in the prevention of HIV pathogenesis and for the design of new vaccine candidates.
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24
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Surface-bound Tat inhibits antigen-specific CD8+ T-cell activation in an integrin-dependent manner. AIDS 2014; 28:2189-200. [PMID: 25313583 DOI: 10.1097/qad.0000000000000389] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The identification of still unrevealed mechanisms affecting the anti-HIV CD8 T-cell response in HIV-1 infection. DESIGN Starting from the observation that anti-Tat immunization is associated with improved CD8 T-cell immunity, we developed both in-vitro and ex-vivo assays to characterize the effects of extra-cellular Tat on the adaptive CD8 T-cell response. METHODS The effects of Tat on CD8 T-cell activation were assayed using CD8 T-cell clones specific for either cellular (MART-1) or viral (HIV-1 Nef) antigens, and HIV-1 Gag-specific CD8 T cells from HIV-1 patients. RESULTS The interaction between CD8 T lymphocytes and immobilized Tat, but not its soluble form, inhibits peptide-specific CD8 T-lymphocyte activation. The inhibition does not depend on Tat trans-activation activity, but on the interaction of the Tat RGD domain with α5β1 and αvβ3 integrins. Impaired CD8 T-cell activation was also observed in cocultures of CD8 T cells with HIV-1-infected cells. Anti-Tat Abs abrogate the inhibitory effect, consistently with the evidence that extracellular Tat accumulates on the cell membrane of virus-producing cells. The Tat-induced inhibition of cell activation associates with increased apoptosis of CD8 T cells. Finally, the inhibition of cell activation also takes place in Gag-specific CD8 T lymphocytes from HIV-1-infected patients. CONCLUSION Our results support the idea that CD8 T-cell apoptosis induced by surface-bound extracellular Tat can contribute to the dysregulation of the CD8 T-cell adaptive response against HIV as well as other pathogens present in AIDS patients.
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Sicurella M, Nicoli F, Gallerani E, Volpi I, Berto E, Finessi V, Destro F, Manservigi R, Cafaro A, Ensoli B, Caputo A, Gavioli R, Marconi PC. An attenuated herpes simplex virus type 1 (HSV1) encoding the HIV-1 Tat protein protects mice from a deadly mucosal HSV1 challenge. PLoS One 2014; 9:e100844. [PMID: 25033084 PMCID: PMC4102458 DOI: 10.1371/journal.pone.0100844] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 05/30/2014] [Indexed: 12/22/2022] Open
Abstract
Herpes simplex virus types 1 and 2 (HSV1 and HSV2) are common infectious agents in both industrialized and developing countries. They cause recurrent asymptomatic and/or symptomatic infections, and life-threatening diseases and death in newborns and immunocompromised patients. Current treatment for HSV relies on antiviral medications, which can halt the symptomatic diseases but cannot prevent the shedding that occurs in asymptomatic patients or, consequently, the spread of the viruses. Therefore, prevention rather than treatment of HSV infections has long been an area of intense research, but thus far effective anti-HSV vaccines still remain elusive. One of the key hurdles to overcome in anti-HSV vaccine development is the identification and effective use of strategies that promote the emergence of Th1-type immune responses against a wide range of epitopes involved in the control of viral replication. Since the HIV1 Tat protein has several immunomodulatory activities and increases CTL recognition of dominant and subdominant epitopes of heterologous antigens, we generated and assayed a recombinant attenuated replication-competent HSV1 vector containing the tat gene (HSV1-Tat). In this proof-of-concept study we show that immunization with this vector conferred protection in 100% of mice challenged intravaginally with a lethal dose of wild-type HSV1. We demonstrate that the presence of Tat within the recombinant virus increased and broadened Th1-like and CTL responses against HSV-derived T-cell epitopes and elicited in most immunized mice detectable IgG responses. In sharp contrast, a similarly attenuated HSV1 recombinant vector without Tat (HSV1-LacZ), induced low and different T cell responses, no measurable antibody responses and did not protect mice against the wild-type HSV1 challenge. These findings strongly suggest that recombinant HSV1 vectors expressing Tat merit further investigation for their potential to prevent and/or contain HSV1 infection and dissemination.
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Affiliation(s)
- Mariaconcetta Sicurella
- Department of Life Sciences and Biotechnology, Section of Applied Microbiology and Pathology, University of Ferrara, Ferrara, Italy
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Francesco Nicoli
- Department of Life Sciences and Biotechnology, Section of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy
| | - Eleonora Gallerani
- Department of Life Sciences and Biotechnology, Section of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy
| | - Ilaria Volpi
- Department of Life Sciences and Biotechnology, Section of Applied Microbiology and Pathology, University of Ferrara, Ferrara, Italy
| | - Elena Berto
- Department of Life Sciences and Biotechnology, Section of Applied Microbiology and Pathology, University of Ferrara, Ferrara, Italy
| | - Valentina Finessi
- Department of Life Sciences and Biotechnology, Section of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy
| | - Federica Destro
- Department of Life Sciences and Biotechnology, Section of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Roberto Manservigi
- Department of Life Sciences and Biotechnology, Section of Applied Microbiology and Pathology, University of Ferrara, Ferrara, Italy
| | - Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Antonella Caputo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Riccardo Gavioli
- Department of Life Sciences and Biotechnology, Section of Biochemistry and Molecular Biology, University of Ferrara, Ferrara, Italy
| | - Peggy C. Marconi
- Department of Life Sciences and Biotechnology, Section of Applied Microbiology and Pathology, University of Ferrara, Ferrara, Italy
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Bellino S, Tripiciano A, Picconi O, Francavilla V, Longo O, Sgadari C, Paniccia G, Arancio A, Angarano G, Ladisa N, Lazzarin A, Tambussi G, Nozza S, Torti C, Focà E, Palamara G, Latini A, Sighinolfi L, Mazzotta F, Di Pietro M, Di Perri G, Bonora S, Mercurio VS, Mussini C, Gori A, Galli M, Monini P, Cafaro A, Ensoli F, Ensoli B. The presence of anti-Tat antibodies in HIV-infected individuals is associated with containment of CD4+ T-cell decay and viral load, and with delay of disease progression: results of a 3-year cohort study. Retrovirology 2014; 11:49. [PMID: 24961156 PMCID: PMC4087126 DOI: 10.1186/1742-4690-11-49] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 06/12/2014] [Indexed: 11/10/2022] Open
Abstract
Background Tat is a key HIV-1 virulence factor, which plays pivotal roles in virus gene expression, replication, transmission and disease progression. After release, extracellular Tat accumulates in tissues and exerts effects on both the virus and the immune system, promoting immune activation and virus spreading while disabling the host immune defense. In particular, Tat binds Env spikes on virus particles forming a virus entry complex, which favors infection of dendritic cells and efficient transmission to T cells via RGD-binding integrins. Tat also shields the CCR5-binding sites of Env rendering ineffective virus neutralization by anti-Env antibodies (Abs). This is reversed by the anti-Tat Abs present in natural infection or induced by vaccination. Findings Here we present the results of a cohort study, showing that the presence of anti-Tat Abs in asymptomatic and treatment-naïve HIV-infected subjects is associated with containment of CD4+ T-cell loss and viral load and with a delay of disease progression. In fact, no subjects with high anti-Tat Ab titers initiated antiretroviral therapy during the three years of follow-up. In contrast, no significant effects were seen for anti-Env and anti-Gag Abs. The increase of anti-Env Ab titers was associated with a reduced risk of starting therapy only in the presence of anti-Tat Abs, suggesting an effect of combined anti-Tat and anti-Env Abs on the Tat/Env virus entry complex and on virus neutralization. Conclusions Anti-Tat immunity may help delay HIV disease progression, thus, targeting Tat may offer a novel therapeutic intervention to postpone antiretroviral treatment or to increase its efficacy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
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HIV-1 Tat protein induces PD-L1 (B7-H1) expression on dendritic cells through tumor necrosis factor alpha- and toll-like receptor 4-mediated mechanisms. J Virol 2014; 88:6672-89. [PMID: 24696476 DOI: 10.1128/jvi.00825-14] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Chronic human immunodeficiency virus type 1 (HIV-1) infection is associated with induction of T-cell coinhibitory pathways. However, the mechanisms by which HIV-1 induces upregulation of coinhibitory molecules remain to be fully elucidated. The aim of the present study was to determine whether and how HIV-1 Tat protein, an immunosuppressive viral factor, induces the PD-1/PD-L1 coinhibitory pathway on human dendritic cells (DCs). We found that treatment of DCs with whole HIV-1 Tat protein significantly upregulated the level of expression of PD-L1. This PD-L1 upregulation was observed in monocyte-derived dendritic cells (MoDCs) obtained from either uninfected or HIV-1-infected patients as well as in primary myeloid DCs from HIV-negative donors. In contrast, no effect on the expression of PD-L2 or PD-1 molecules was detected. The induction of PD-L1 on MoDCs by HIV-1 Tat (i) occurred in dose- and time-dependent manners, (ii) was mediated by the N-terminal 1-45 fragment of Tat, (iii) did not require direct cell-cell contact but appeared rather to be mediated by soluble factor(s), (iv) was abrogated following neutralization of tumor necrosis factor alpha (TNF-α) or blocking of Toll-like receptor 4 (TLR4), (v) was absent in TLR4-knockoout (KO) mice but could be restored following incubation with Tat-conditioned medium from wild-type DCs, (vi) impaired the capacity of MoDCs to functionally stimulate T cells, and (vii) was not reversed functionally following PD-1/PD-L1 pathway blockade, suggesting the implication of other Tat-mediated coinhibitory pathways. Our results demonstrate that HIV-1 Tat protein upregulates PD-L1 expression on MoDCs through TNF-α- and TLR4-mediated mechanisms, functionally compromising the ability of DCs to stimulate T cells. The findings offer a novel potential molecular target for the development of an anti-HIV-1 treatment. IMPORTANCE The objective of this study was to investigate the effect of human immunodeficiency virus type 1 (HIV-1) Tat on the PD-1/PD-L1 coinhibitory pathway on human monocyte-derived dendritic cells (MoDCs). We found that treatment of MoDCs from either healthy or HIV-1-infected patients with HIV-1 Tat protein stimulated the expression of PD-L1. We demonstrate that this stimulation was mediated through an indirect mechanism, involving tumor necrosis factor alpha (TNF-α) and Toll-like receptor 4 (TLR4) pathways, and resulted in compromised ability of Tat-treated MoDCs to functionally stimulate T-cell proliferation.
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Nicoli F, Finessi V, Sicurella M, Rizzotto L, Gallerani E, Destro F, Cafaro A, Marconi P, Caputo A, Ensoli B, Gavioli R. The HIV-1 Tat protein induces the activation of CD8+ T cells and affects in vivo the magnitude and kinetics of antiviral responses. PLoS One 2013; 8:e77746. [PMID: 24223723 PMCID: PMC3817196 DOI: 10.1371/journal.pone.0077746] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/06/2013] [Indexed: 11/19/2022] Open
Abstract
T cells are functionally compromised during HIV infection despite their increased activation and proliferation. Although T cell hyperactivation is one of the best predictive markers for disease progression, its causes are poorly understood. Anti-tat natural immunity as well as anti-tat antibodies induced by Tat immunization protect from progression to AIDS and reverse signs of immune activation in HIV-infected patients suggesting a role of Tat in T cell dysfunctionality. The Tat protein of HIV-1 is known to induce, in vitro, the activation of CD4(+) T lymphocytes, but its role on CD8(+) T cells and how these effects modulate, in vivo, the immune response to pathogens are not known. To characterize the role of Tat in T cell hyperactivation and dysfunction, we examined the effect of Tat on CD8(+) T cell responses and antiviral immunity in different ex vivo and in vivo models of antigenic stimulation, including HSV infection. We demonstrate for the first time that the presence of Tat during priming of CD8(+) T cells favors the activation of antigen-specific CTLs. Effector CD8(+) T cells generated in the presence of Tat undergo an enhanced and prolonged expansion that turns to a partial dysfunctionality at the peak of the response, and worsens HSV acute infection. Moreover, Tat favors the development of effector memory CD8(+) T cells and a transient loss of B cells, two hallmarks of the chronic immune activation observed in HIV-infected patients. Our data provide evidence that Tat affects CD8(+) T cell responses to co-pathogens and suggest that Tat may contribute to the CD8(+) T cell hyperactivation observed in HIV-infected individuals.
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Affiliation(s)
- Francesco Nicoli
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Valentina Finessi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Mariaconcetta Sicurella
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Lara Rizzotto
- Department of Biomedical Sciences, Azienda Ospedaliero Universitaria Sant'Anna, Ferrara, Italy
| | - Eleonora Gallerani
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Federica Destro
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Peggy Marconi
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Antonella Caputo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Riccardo Gavioli
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
- * E-mail:
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Liu Y, Li F, Qi Z, Hao Y, Hong K, Liu Y, Cong Y, Shao Y. The effects of HIV Tat DNA on regulating the immune response of HIV DNA vaccine in mice. Virol J 2013; 10:297. [PMID: 24073803 PMCID: PMC3851266 DOI: 10.1186/1743-422x-10-297] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 09/04/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND HIV trans-activator protein (Tat) is the crucial factor to control HIV transcription, and is usually considered as an important immunogen for the design of HIV vaccine. Recent studies reported some special bio-activities of Tat protein on immunoregulation. However, to date, few studies have focused on exploring the effects of Tat expression plasmid (pTat) on regulating the immune responses induced by HIV DNA vaccines. In this study, our main objective is to investigate the immunoregulation mediated by pTat in mice. METHODS Four gene-coding plasmids (pTat, pGag, pEnv and pPol) were constructed, and the gene expression was detected by western blot method. The effects of pTat on regulating the immune responses to antigens Gag, Env, Pol were assessed by enzyme-linked immunospot and enzyme-linked immunosorbent assay. The data was analysed by one-way analysis of variance. RESULTS After two immunizations, mice vaccinated with antigen expressing plasmid (pGag, pEnv or pPol) plus pTat exhibited significantly stronger IFN-gamma response than that vaccinated with the corresponding antigen alone. Moreover, mice receiving two injections of antigen plus pTat exhibited the same strong IFN-gamma response as those receiving three injections of antigen alone did. Furthermore, addition of pTat not only induced a more balanced Th1 and Th2 response, but also broadened IgG subclass responses to antigens Gag and Pol. CONCLUSION pTat exhibited the appreciable effects on modulating immune responses to HIV antigens Gag, Env and Pol, providing us interesting clues on how to optimize HIV DNA vaccine.
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MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/genetics
- AIDS Vaccines/immunology
- Animals
- Female
- Interferon-gamma/metabolism
- Mice
- Vaccination/methods
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- env Gene Products, Human Immunodeficiency Virus/genetics
- env Gene Products, Human Immunodeficiency Virus/immunology
- gag Gene Products, Human Immunodeficiency Virus/genetics
- gag Gene Products, Human Immunodeficiency Virus/immunology
- pol Gene Products, Human Immunodeficiency Virus/genetics
- pol Gene Products, Human Immunodeficiency Virus/immunology
- tat Gene Products, Human Immunodeficiency Virus/genetics
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Affiliation(s)
- Ye Liu
- Department of Clinical Laboratory, Chinese P. L. A. General Hospital, No. 28 Fuxing Road, Beijing 100853, China
| | - Fusheng Li
- Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue N, Seattle, WA 98109, USA
| | - Zhi Qi
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Road Changping District, Beijing 102206, China
| | - Yanling Hao
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Road Changping District, Beijing 102206, China
| | - Kunxue Hong
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Road Changping District, Beijing 102206, China
| | - Yong Liu
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Road Changping District, Beijing 102206, China
| | - Yulong Cong
- Department of Clinical Laboratory, Chinese P. L. A. General Hospital, No. 28 Fuxing Road, Beijing 100853, China
| | - Yiming Shao
- State Key Laboratory for Infectious Disease Prevention and Control, National Center for AIDS/STD Control and Prevention, Chinese Center for Disease Control and Prevention, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, 155 Changbai Road Changping District, Beijing 102206, China
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Demberg T, Brocca-Cofano E, Kuate S, Aladi S, Vargas-Inchaustegui DA, Venzon D, Kalisz I, Kalyanaraman V, Lee EM, Pal R, DiPasquale J, Ruprecht RM, Montefiori DC, Srivastava I, Barnett SW, Robert-Guroff M. Impact of antibody quality and anamnestic response on viremia control post-challenge in a combined Tat/Env vaccine regimen in rhesus macaques. Virology 2013; 440:210-21. [PMID: 23528732 PMCID: PMC3744165 DOI: 10.1016/j.virol.2013.02.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/03/2012] [Accepted: 02/27/2013] [Indexed: 11/18/2022]
Abstract
Previously, priming rhesus macaques with Adenovirus type 5 host range mutant-recombinants encoding Tat and Env and boosting with Tat and Env protein in MPL-SE controlled chronic viremia by 4 logs following homologous intravenous SHIV89.6P challenge. Here we evaluated Tat, Env, and Tat/Env regimens for immunogenicity and protective efficacy using clade C Env, alum adjuvant, and a heterologous intrarectal SHIV1157ipd3N4 challenge. Despite induction of strong cellular and humoral immunity, Tat/Env group T and B-cell memory responses were not significantly enhanced over Tat- or Env-only groups. Lack of viremia control post-challenge was attributed to lower avidity Env antibodies and no anamnestic ADCC response or SHIV1157ipd3N4 neutralizing antibody development post-challenge. Poor biologic activity of the Tat immunogen may have impaired Tat immunity. In the absence of sterilizing immunity, strong anamnestic responses to heterologous virus can help control viremia. Both antibody breadth and optimal adjuvanticity are needed to elicit high-quality antibody for protective efficacy.
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Affiliation(s)
- Thorsten Demberg
- Vaccine Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - Seraphin Kuate
- Vaccine Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | - Stanley Aladi
- Vaccine Branch, National Cancer Institute, Bethesda, MD 20892, USA
| | | | - David Venzon
- Biostatistics and Data Management Section, National Cancer Institute, Bethesda, MD 20892, USA
| | - Irene Kalisz
- Advanced BioScience Laboratories, Inc., Kensington, MD 20895, USA
| | | | - Eun Mi Lee
- Advanced BioScience Laboratories, Inc., Kensington, MD 20895, USA
| | - Ranajit Pal
- Advanced BioScience Laboratories, Inc., Kensington, MD 20895, USA
| | - Janet DiPasquale
- Vaccine Branch, National Cancer Institute, Bethesda, MD 20892, USA
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Monini P, Cafaro A, Srivastava IK, Moretti S, Sharma VA, Andreini C, Chiozzini C, Ferrantelli F, Cossut MRP, Tripiciano A, Nappi F, Longo O, Bellino S, Picconi O, Fanales-Belasio E, Borsetti A, Toschi E, Schiavoni I, Bacigalupo I, Kan E, Sernicola L, Maggiorella MT, Montin K, Porcu M, Leone P, Leone P, Collacchi B, Palladino C, Ridolfi B, Falchi M, Macchia I, Ulmer JB, Buttò S, Sgadari C, Magnani M, Federico MPM, Titti F, Banci L, Dallocchio F, Rappuoli R, Ensoli F, Barnett SW, Garaci E, Ensoli B. HIV-1 tat promotes integrin-mediated HIV transmission to dendritic cells by binding Env spikes and competes neutralization by anti-HIV antibodies. PLoS One 2012; 7:e48781. [PMID: 23152803 PMCID: PMC3496724 DOI: 10.1371/journal.pone.0048781] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 10/01/2012] [Indexed: 12/31/2022] Open
Abstract
Use of Env in HIV vaccine development has been disappointing. Here we show that, in the presence of a biologically active Tat subunit vaccine, a trimeric Env protein prevents in monkeys virus spread from the portal of entry to regional lymph nodes. This appears to be due to specific interactions between Tat and Env spikes that form a novel virus entry complex favoring R5 or X4 virus entry and productive infection of dendritic cells (DCs) via an integrin-mediated pathway. These Tat effects do not require Tat-transactivation activity and are blocked by anti-integrin antibodies (Abs). Productive DC infection promoted by Tat is associated with a highly efficient virus transmission to T cells. In the Tat/Env complex the cysteine-rich region of Tat engages the Env V3 loop, whereas the Tat RGD sequence remains free and directs the virus to integrins present on DCs. V2 loop deletion, which unshields the CCR5 binding region of Env, increases Tat/Env complex stability. Of note, binding of Tat to Env abolishes neutralization of Env entry or infection of DCs by anti-HIV sera lacking anti-Tat Abs, which are seldom present in natural infection. This is reversed, and neutralization further enhanced, by HIV sera containing anti-Tat Abs such as those from asymptomatic or Tat-vaccinated patients, or by sera from the Tat/Env vaccinated monkeys. Thus, both anti-Tat and anti-Env Abs are required for efficient HIV neutralization. These data suggest that the Tat/Env interaction increases HIV acquisition and spreading, as a mechanism evolved by the virus to escape anti-Env neutralizing Abs. This may explain the low effectiveness of Env-based vaccines, which are also unlikely to elicit Abs against new Env epitopes exposed by the Tat/Env interaction. As Tat also binds Envs from different clades, new vaccine strategies should exploit the Tat/Env interaction for both preventative and therapeutic interventions.
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MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/immunology
- Animals
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/metabolism
- Binding Sites
- Dendritic Cells/immunology
- Dendritic Cells/virology
- HIV Antibodies/immunology
- HIV Antibodies/metabolism
- HIV Envelope Protein gp120/immunology
- HIV Envelope Protein gp120/metabolism
- HIV Infections/immunology
- HIV Infections/prevention & control
- HIV Infections/transmission
- HIV Infections/virology
- HIV-1/immunology
- HIV-1/metabolism
- Humans
- Integrins/immunology
- Integrins/metabolism
- Macaca fascicularis
- Male
- Molecular Docking Simulation
- Neutralization Tests
- Oligopeptides/metabolism
- Protein Binding
- Protein Interaction Domains and Motifs/immunology
- Receptors, CCR5/metabolism
- Receptors, CXCR4/metabolism
- Recombinant Proteins/immunology
- Recombinant Proteins/isolation & purification
- Recombinant Proteins/metabolism
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- T-Lymphocytes/virology
- Vaccines, Virus-Like Particle/administration & dosage
- Vaccines, Virus-Like Particle/immunology
- Virus Internalization
- Virus Replication
- env Gene Products, Human Immunodeficiency Virus/chemistry
- env Gene Products, Human Immunodeficiency Virus/immunology
- env Gene Products, Human Immunodeficiency Virus/metabolism
- tat Gene Products, Human Immunodeficiency Virus/chemistry
- tat Gene Products, Human Immunodeficiency Virus/immunology
- tat Gene Products, Human Immunodeficiency Virus/metabolism
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Affiliation(s)
- Paolo Monini
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Indresh K. Srivastava
- Novartis Vaccines & Diagnostics, Inc., Cambridge, Massachusetts, United States of America
| | - Sonia Moretti
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Victoria A. Sharma
- Novartis Vaccines & Diagnostics, Inc., Cambridge, Massachusetts, United States of America
| | | | | | | | | | - Antonella Tripiciano
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
- San Gallicano Hospital, Rome, Italy
| | - Filomena Nappi
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Olimpia Longo
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | | | - Orietta Picconi
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | | | | | - Elena Toschi
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | | | | | - Elaine Kan
- Novartis Vaccines & Diagnostics, Inc., Cambridge, Massachusetts, United States of America
| | | | | | - Katy Montin
- Department of Biochemistry, University of Ferrara, Ferrara, Italy
| | - Marco Porcu
- CERM, University of Florence, Florence, Italy
| | - Patrizia Leone
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | | | | | | | - Barbara Ridolfi
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Mario Falchi
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Iole Macchia
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Jeffrey B. Ulmer
- Novartis Vaccines & Diagnostics, Inc., Cambridge, Massachusetts, United States of America
| | - Stefano Buttò
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Cecilia Sgadari
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Mauro Magnani
- Department of Biomolecular Science, University of Urbino, Urbino, Italy
| | | | - Fausto Titti
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Lucia Banci
- CERM, University of Florence, Florence, Italy
| | | | | | | | - Susan W. Barnett
- Novartis Vaccines & Diagnostics, Inc., Cambridge, Massachusetts, United States of America
| | - Enrico Garaci
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
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Li P, Sheng J, Liu Y, Li J, Liu J, Wang F. Heparosan-derived heparan sulfate/heparin-like compounds: one kind of potential therapeutic agents. Med Res Rev 2012; 33:665-92. [PMID: 22495734 DOI: 10.1002/med.21263] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Heparan sulfate (HS) is a highly sulfated glycosaminoglycan and exists in all animal tissues. HS and heparin are very similar, except that heparin has higher level of sulfation and higher content of iduronic acid. Despite the fact that it is a century-old drug, heparin remains as a top choice for treating thrombotic disorders. Pharmaceutical heparin is derived from porcine intestine or bovine lung via a long supply chain. This supply chain is vulnerable to the contamination of animal pathogens. Therefore, new methods for manufacturing heparin or heparin-like substances devoid of animal tissues have been explored by many researchers, among which, modifications of heparosan, the capsular polysaccharide of Escherichia coli K5 strain, is one of the promising approaches. Heparosan has a structure similar to unmodified backbone of natural HS and heparin. It is feasible to obtain HS or heparin derivatives by modifying heparosan with chemical or enzymatic methods. These derivatives display different biological activities, such as anticoagulant, anti-inflammatory, anticancer, and antiviral activities. This review focuses on the recent studies of synthesis, activity, and structure-activity relationship of HS/heparin-like derivatives prepared from heparosan.
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Affiliation(s)
- Pingli Li
- Institute of Biochemical and Biotechnological Drug & National Glycoengineering Research Center, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China
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Honda JR, Shang S, Shanley CA, Caraway ML, Henao-Tamayo M, Chan ED, Basaraba RJ, Orme IM, Ordway DJ, Flores SC. Immune Responses of HIV-1 Tat Transgenic Mice to Mycobacterium Tuberculosis W-Beijing SA161. Open AIDS J 2011; 5:86-95. [PMID: 22046211 PMCID: PMC3204420 DOI: 10.2174/1874613601105010086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Revised: 04/22/2011] [Accepted: 05/11/2011] [Indexed: 11/30/2022] Open
Abstract
Background: Mycobacterium tuberculosis remains among the leading causes of death from an infectious agent in the world and exacerbates disease caused by the human immunodeficiency virus (HIV). HIV infected individuals are prone to lung infections by a variety of microbial pathogens, including M. tuberculosis. While the destruction of the adaptive immune response by HIV is well understood, the actual pathogenesis of tuberculosis in co-infected individuals remains unclear. Tat is an HIV protein essential for efficient viral gene transcription, is secreted from infected cells, and is known to influence a variety of host inflammatory responses. We hypothesize Tat contributes to pathophysiological changes in the lung microenvironment, resulting in impaired host immune responses to infection by M. tuberculosis. Results: Herein, we show transgenic mice that express Tat by lung alveolar cells are more susceptible than non-transgenic control littermates to a low-dose aerosol infection of M. tuberculosis W-Beijing SA161. Survival assays demonstrate accelerated mortality rates of the Tat transgenic mice compared to non-transgenics. Tat transgenic mice also showed poorly organized lung granulomata-like lesions. Analysis of the host immune response using quantitative RT-PCR, flow cytometry for surface markers, and intracellular cytokine staining showed increased expression of pro-inflammatory cytokines in the lungs, increased numbers of cells expressing ICAM1, increased numbers of CD4+CD25+Foxp3+ T regulatory cells, and IL-4 producing CD4+ T cells in the Tat transgenics compared to infected non-tg mice. Conclusions: Our data show quantitative differences in the inflammatory response to the SA161 clinical isolate of M. tuberculosis W-Beijing between Tat transgenic and non-transgenic mice, suggesting Tat contributes to the pathogenesis of tuberculosis.
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Affiliation(s)
- Jennifer R Honda
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado, Anschutz Medical Campus, Aurora, Colorado, 80045, USA
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Fibroblast Growth Factor-2 and the HIV-1 Tat Protein Synergize in Promoting Bcl-2 Expression and Preventing Endothelial Cell Apoptosis: Implications for the Pathogenesis of AIDS-Associated Kaposi's Sarcoma. Int J Vasc Med 2011; 2011:452729. [PMID: 22007303 PMCID: PMC3189568 DOI: 10.1155/2011/452729] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 07/18/2011] [Accepted: 07/24/2011] [Indexed: 12/22/2022] Open
Abstract
Kaposi's sarcoma (KS) is a vascular tumor frequently occurring in Human Immunodeficiency Virus- (HIV-) 1-infected individuals.
Our previous work indicated that the angiogenic fibroblast growth factor (FGF)-2 and the Tat protein of HIV-1, both expressed in KS lesions of HIV-infected patients, synergize at inducing angioproliferative, KS-like lesions in mice.
Here we show that the development of angioproliferative lesions promoted in mice by combined Tat and FGF-2 associates with an increase in the levels of expression of the antiapoptotic Bcl-2 protein. Upregulation of Bcl-2 expression by combined FGF-2 and Tat occurs also in vitro, and this protects human primary endothelial cells from programmed cell death.
As Bcl-2 is expressed in human KS lesions in a fashion paralleling the progression of the disease, these findings suggest a molecular mechanism by which Tat and FGF-2 cooperate in KS maintenance and progression in HIV-infected individuals.
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Modulation of Th1/Th2 immune responses to HIV-1 Tat by new pro-GSH molecules. Vaccine 2011; 29:6823-9. [PMID: 21816192 DOI: 10.1016/j.vaccine.2011.07.101] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 06/15/2011] [Accepted: 07/21/2011] [Indexed: 11/23/2022]
Abstract
We have previously demonstrated that in Ova-immunized mice the increase in intra-macrophage thiol pool induced by pro-GSH molecules modulates the Th1/Th2 balance in favour of a Th1-type immune response. We show now that the same molecules can support a Th1-type over Th2-type immunity against Tat, which is an early HIV-1 regulatory protein and a Th1 polarizing immunomodulator that is increasingly considered in new anti-HIV vaccination strategies. Our results indicate that Tat-immunized mice pre-treated with the C4 (n-butanoyl) derivative of reduced glutathione (GSH-C4) or a pro-drug of N-acetylcysteine (NAC) and beta-mercaptoethylamine (MEA) (I-152), have decreased levels of anti-Tat IgG1 as well as increased levels of anti-Tat IgG2a and IgG2b isotypes suggesting a Th1-type response. Moreover, Th1-(IFN-γ and IL-2) Ag-specific cellular responses were detected by ELISPOT assay in splenocytes of the same animals as well as an increase of IL-12 levels in the plasma. These findings suggest that the Th1 immune response to HIV-1 Tat could be further polarized by these molecules. These results together with those previously reported suggest that pro-GSH molecules could be used to modulate the immune response towards different antigens and may be further exploited for inducing specific Th1 immune responses against other HIV antigens as well as other intracellular pathogens in new Tat-based vaccination protocols.
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Ferrantelli F, Maggiorella MT, Schiavoni I, Sernicola L, Olivieri E, Farcomeni S, Pavone-Cossut MR, Moretti S, Belli R, Collacchi B, Srivastava IK, Titti F, Cafaro A, Barnett SW, Ensoli B. A combination HIV vaccine based on Tat and Env proteins was immunogenic and protected macaques from mucosal SHIV challenge in a pilot study. Vaccine 2011; 29:2918-32. [PMID: 21338681 DOI: 10.1016/j.vaccine.2011.02.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 01/31/2011] [Accepted: 02/05/2011] [Indexed: 02/02/2023]
Abstract
HIV native Tat and V2 loop-deleted Env (EnvΔV2) proteins already proved safe and immunogenic in phase I clinical testing as single vaccine components. Further, a phase II vaccine trial with Tat showed intensification of the therapeutic effects of HAART in successfully treated HIV-infected individuals. Here a pilot study assessed the immunogenicity and protective efficacy of an HIV/AIDS vaccine based on the combination of Tat and EnvΔV2 proteins in cynomolgus macaques against homologous intrarectal challenge with 35 MID(50) (monkey infectious dose 50) of an R5 simian-human immunodeficiency virus (SHIV(SF162P4cy)). Upon challenge, three of four macaques immunized with Tat and EnvΔV2, and two of three monkeys immunized with EnvΔV2 alone were protected from infection. In contrast, all three control animals, which had been either administered with the adjuvants only or left untreated, and an additional monkey immunized with Tat alone became systemically infected. Protection of the macaques vaccinated with EnvΔV2 or Tat/EnvΔV2 correlated with higher peak titers of pre-challenge neutralizing antibodies obtained during the immunization period (between 70 and 3 weeks before challenge) and with anti-Env V3 loop binding antibodies assessed 3 weeks before challenge. Compared to EnvΔV2 alone, the Tat and EnvΔV2 combined vaccine elicited faster antibody responses (IgM) with a trend, early in the vaccination schedule, after the second immunization including EnvΔV2, towards broader anti-Env IgG epitope specificity and a higher ratio of neutralizing to Env-binding antibody titers. As the number of immunizations increased, vaccination with EnvΔV2 approached the immune response assessed after two inocula with the Tat/EnvΔV2 combined vaccine, even though some differences remained between groups, as indicated by anti-Env IgG epitope mapping. In fact, three weeks before challenge, plasma IgG of animals in the EnvΔV2 group showed a trend towards stronger specificity for the V1 loop and V5 loop-C5 regions of Env, whereas the Tat/EnvΔV2 group displayed an overall higher reactivity for epitopes within the Env V3 loop throughout the immunization period. Although differences in terms of protection rate were not found between the EnvΔV2 or Tat/EnvΔV2 vaccination groups in this pilot study, vaccination with Tat/EnvΔV2 appeared to accelerate the induction of potentially protective antibody responses to Env. In particular, antibodies to the Env V3 loop, whose levels at pre-challenge correlated with protection, were already higher early in the vaccination schedule in monkeys immunized with Tat/EnvΔV2 as compared to EnvΔV2 alone. Further studies including larger vaccination groups and fewer immunizations with these two vaccine candidates are needed to confirm these findings and to assess whether the Tat/EnvΔV2 vaccine may afford superior protection against infection.
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Affiliation(s)
- Flavia Ferrantelli
- National AIDS Center, Istituto Superiore di Sanità, Viale Regina Elena, 299 00161 Rome, Italy
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Johri MK, Mishra R, Chhatbar C, Unni SK, Singh SK. Tits and bits of HIV Tat protein. Expert Opin Biol Ther 2011; 11:269-83. [PMID: 21204735 DOI: 10.1517/14712598.2011.546339] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION HIV-Tat protein displays an array of functions that are essential for HIV replication. The structural flexibility of Tat protein has been regarded as one of the unique features responsible for sustaining diverse functions, from facilitated membrane-crossing ability to strong affinity for RNA binding. AREAS COVERED RNA binding ability and presence of multiple interacting domains in the same protein are very important properties of HIV-Tat protein. Tat protein has shown great ability to influence cellular and viral gene expression. We discuss the functions of HIV Tat protein, describing its structural significance, secretion and uptake of HIV Tat protein by immune cells, post-translational modifications and role of HIV Tat protein in HIV pathogenesis. EXPERT OPINION Perturbation in expression of many cytokines and chemokines by HIV-Tat protein exhibits downstream immune suppressive function as well as activation of several apoptotic genes. This explains the massive death of immune cells due to bystander effect of HIV Tat protein among HIV-infected patients.
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Affiliation(s)
- Manish K Johri
- Laboratory of Neurovirology & Inflammation Biology, Section of Infectious Diseases, Centre for Cellular and Molecular Biology, Council of Scientific and Industrial Research, Uppal Road, Hyderabad-500007, (A.P), India
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Ensoli B, Bellino S, Tripiciano A, Longo O, Francavilla V, Marcotullio S, Cafaro A, Picconi O, Paniccia G, Scoglio A, Arancio A, Ariola C, Ruiz Alvarez MJ, Campagna M, Scaramuzzi D, Iori C, Esposito R, Mussini C, Ghinelli F, Sighinolfi L, Palamara G, Latini A, Angarano G, Ladisa N, Soscia F, Mercurio VS, Lazzarin A, Tambussi G, Visintini R, Mazzotta F, Di Pietro M, Galli M, Rusconi S, Carosi G, Torti C, Di Perri G, Bonora S, Ensoli F, Garaci E. Therapeutic immunization with HIV-1 Tat reduces immune activation and loss of regulatory T-cells and improves immune function in subjects on HAART. PLoS One 2010; 5:e13540. [PMID: 21085635 PMCID: PMC2978690 DOI: 10.1371/journal.pone.0013540] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Accepted: 09/28/2010] [Indexed: 11/18/2022] Open
Abstract
Although HAART suppresses HIV replication, it is often unable to restore immune homeostasis. Consequently, non-AIDS-defining diseases are increasingly seen in treated individuals. This is attributed to persistent virus expression in reservoirs and to cell activation. Of note, in CD4+ T cells and monocyte-macrophages of virologically-suppressed individuals, there is continued expression of multi-spliced transcripts encoding HIV regulatory proteins. Among them, Tat is essential for virus gene expression and replication, either in primary infection or for virus reactivation during HAART, when Tat is expressed, released extracellularly and exerts, on both the virus and the immune system, effects that contribute to disease maintenance. Here we report results of an ad hoc exploratory interim analysis (up to 48 weeks) on 87 virologically-suppressed HAART-treated individuals enrolled in a phase II randomized open-label multicentric clinical trial of therapeutic immunization with Tat (ISS T-002). Eighty-eight virologically-suppressed HAART-treated individuals, enrolled in a parallel prospective observational study at the same sites (ISS OBS T-002), served for intergroup comparison. Immunization with Tat was safe, induced durable immune responses, and modified the pattern of CD4+ and CD8+ cellular activation (CD38 and HLA-DR) together with reduction of biochemical activation markers and persistent increases of regulatory T cells. This was accompanied by a progressive increment of CD4+ T cells and B cells with reduction of CD8+ T cells and NK cells, which were independent from the type of antiretroviral regimen. Increase in central and effector memory and reduction in terminally-differentiated effector memory CD4+ and CD8+ T cells were accompanied by increases of CD4+ and CD8+ T cell responses against Env and recall antigens. Of note, more immune-compromised individuals experienced greater therapeutic effects. In contrast, these changes were opposite, absent or partial in the OBS population. These findings support the use of Tat immunization to intensify HAART efficacy and to restore immune homeostasis.
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Affiliation(s)
- Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
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Fraternale A, Paoletti MF, Dominici S, Caputo A, Castaldello A, Millo E, Brocca-Cofano E, Smietana M, Clayette P, Oiry J, Benatti U, Magnani M. The increase in intra-macrophage thiols induced by new pro-GSH molecules directs the Th1 skewing in ovalbumin immunized mice. Vaccine 2010; 28:7676-82. [DOI: 10.1016/j.vaccine.2010.09.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 09/08/2010] [Accepted: 09/12/2010] [Indexed: 10/19/2022]
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Effect of the redox state on HIV-1 tat protein multimerization and cell internalization and trafficking. Mol Cell Biochem 2010; 345:105-18. [PMID: 20721684 DOI: 10.1007/s11010-010-0564-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Accepted: 07/29/2010] [Indexed: 12/12/2022]
Abstract
The redox state of the cysteine-rich region of the HIV Tat protein is known to play a crucial role in Tat biological activity. In this article, we show that Tat displays two alternative functional states depending on the presence of either one or three reduced sulphydryl groups in the cysteine-rich region, respectively. Using different approaches, a disulfide pattern has been defined for the Tat protein and a specific DTT-dependent breaking order of disulfide bonds highlighted. The Tat redox state deeply influences macrophage protein uptake. Immunoistochemistry analysis shows that the oxidized protein does not enter cells, whereas partially reduced protein reaches the cytosol and, to a limited extent, the nucleus. Finally electrophoretic analysis shows Tat high-molecular weight multi-aggregation, resulting in the loss of biological activity. This is due to strong electrostatic and metal-binding interactions, whereas Tat dimerization involves metal-binding interactions as well as disulfide bond formation.
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Caputo A, Gavioli R, Bellino S, Longo O, Tripiciano A, Francavilla V, Sgadari C, Paniccia G, Titti F, Cafaro A, Ferrantelli F, Monini P, Ensoli F, Ensoli B. HIV-1 Tat-based vaccines: an overview and perspectives in the field of HIV/AIDS vaccine development. Int Rev Immunol 2009; 28:285-334. [PMID: 19811313 DOI: 10.1080/08830180903013026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The HIV epidemic continues to represent one of the major problems worldwide, particularly in the Asia and Sub-Saharan regions of the world, with social and economical devastating effects. Although antiretroviral drugs have had a dramatically beneficial impact on HIV-infected individuals that have access to treatment, it has had a negligible impact on the global epidemic. Hence, the inexorable spreading of the HIV pandemic and the increasing deaths from AIDS, especially in developing countries, underscore the urgency for an effective vaccine against HIV/AIDS. However, the generation of such a vaccine has turned out to be extremely challenging. Here we provide an overview on the rationale for the use of non-structural HIV proteins, such as the Tat protein, alone or in combination with other HIV early and late structural HIV antigens, as novel, promising preventative and therapeutic HIV/AIDS vaccine strategies.
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Affiliation(s)
- Antonella Caputo
- Department of Histology, Microbiology and Medical Biotechnology, University of Padova, Padova, Italy
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Ensoli B, Fiorelli V, Ensoli F, Lazzarin A, Visintini R, Narciso P, Di Carlo A, Tripiciano A, Longo O, Bellino S, Francavilla V, Paniccia G, Arancio A, Scoglio A, Collacchi B, Ruiz Alvarez MJ, Tambussi G, Tassan Din C, Palamara G, Latini A, Antinori A, D’Offizi G, Giuliani M, Giulianelli M, Carta M, Monini P, Magnani M, Garaci E. The preventive phase I trial with the HIV-1 Tat-based vaccine. Vaccine 2009; 28:371-8. [DOI: 10.1016/j.vaccine.2009.10.038] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 10/01/2009] [Accepted: 10/12/2009] [Indexed: 10/20/2022]
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Romani B, Engelbrecht S, Glashoff RH. Functions of Tat: the versatile protein of human immunodeficiency virus type 1. J Gen Virol 2009; 91:1-12. [PMID: 19812265 DOI: 10.1099/vir.0.016303-0] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) Tat is a multifunctional protein that contributes to several pathological symptoms of HIV-1 infection as well as playing a critical role in virus replication. Tat is a robust transactivating protein that induces a variety of effects by altering the expression levels of cellular and viral genes. The functions of Tat are therefore primarily related to its role in modulation of gene expression. In this review the functions of HIV-1 Tat that have been well documented, as well as a number of novel functions that have been proposed for this protein, are discussed. Since some of the functions of Tat vary in different cell types in a concentration-dependent manner and because Tat sometimes exerts the same activity through different pathways, study of this protein has at times yielded conflicting and controversial results. Due to its pivotal role in viral replication and in disease pathogenesis, Tat and the cellular pathways targeted by Tat are potential targets for new anti-HIV drugs.
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Affiliation(s)
- Bizhan Romani
- Division of Medical Virology, Department of Pathology, University of Stellenbosch, Tygerberg 7505, South Africa.
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Kashi VP, Jacob RA, Paul S, Nayak K, Satish B, Swaminathan S, Satish KS, Ranga U. HIV-1 Tat-specific IgG antibodies in high-responders target a B-cell epitope in the cysteine-rich domain and block extracellular Tat efficiently. Vaccine 2009; 27:6739-47. [PMID: 19744585 DOI: 10.1016/j.vaccine.2009.08.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 08/19/2009] [Accepted: 08/22/2009] [Indexed: 10/20/2022]
Abstract
Tat, an important regulatory protein of HIV-1, has been implicated in HIV-related pathogenesis. Immune responses to Tat, although underrepresented, confer protection against disease progression, in natural infection and experimental immunization, making Tat an attractive vaccine candidate. Information on immune responses to Tat from India which has the second largest HIV incidence has been lacking. Here we report a cross-sectional study evaluating the humoral response to Tat from a large number of samples from two southern states of India. 14% of the seropositive (63/447) and 4.6% of seronegative samples (7/150) harbored Tat-reactive antibodies. A significant number of the seropositive samples contained high levels of anti-Tat antibodies (31/447) which demonstrated class-switch to IgG1 and bound to Tat with high avidity. Cross-reactivity analysis showed that these antibodies interacted with Tat from different clades with variable degree with the highest interaction with subtype-AE and the least with subtype-B Tat. Importantly, a B-cell epitope in the cysteine-rich domain was found to be the most immunodominant one and antibodies interacting with this epitope blocked extracellular Tat efficiently. To the best of our knowledge this is the first report on immune responses to Tat from Indian populations and the data presented here could significantly contribute to HIV Tat vaccine design.
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Turbant S, Martinon F, Moine G, Le Grand R, Léonetti M. Cynomolgus macaques immunized with two HIV-1 Tat stabilized proteins raise strong and long-lasting immune responses with a pattern of Th1/Th2 response differing from that in mice. Vaccine 2009; 27:5349-56. [DOI: 10.1016/j.vaccine.2009.06.083] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/15/2009] [Accepted: 06/24/2009] [Indexed: 10/20/2022]
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Campbell GR, Loret EP. What does the structure-function relationship of the HIV-1 Tat protein teach us about developing an AIDS vaccine? Retrovirology 2009; 6:50. [PMID: 19467159 PMCID: PMC2693501 DOI: 10.1186/1742-4690-6-50] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 05/25/2009] [Indexed: 11/03/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) trans-activator of transcription protein Tat is an important factor in viral pathogenesis. In addition to its function as the key trans-activator of viral transcription, Tat is also secreted by the infected cell and taken up by neighboring cells where it has an effect both on infected and uninfected cells. In this review we will focus on the relationship between the structure of the Tat protein and its function as a secreted factor. To this end we will summarize some of the exogenous functions of Tat that have been implicated in HIV-1 pathogenesis and the impact of structural variations and viral subtype variants of Tat on those functions. Finally, since in some patients the presence of Tat-specific antibodies or CTL frequencies are associated with slow or non-progression to AIDS, we will also discuss the role of Tat as a potential vaccine candidate, the advances made in this field, and the importance of using a Tat protein capable of eliciting a protective or therapeutic immune response to viral challenge.
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Affiliation(s)
- Grant R Campbell
- Department of Pediatrics, Division of Infectious Diseases, University of California San Diego, La Jolla, California 92093-0672, USA.
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Caputo A, Gavioli R, Bellino S, Longo O, Tripiciano A, Francavilla V, Sgadari C, Paniccia G, Titti F, Cafaro A, Ferrantelli F, Monini P, Ensoli F, Ensoli B. HIV-1 Tat-Based Vaccines: An Overview and Perspectives in the Field of HIV/AIDS Vaccine Development. Int Rev Immunol 2009. [DOI: 10.1080/08830180903013026 10.1080/08830180903013026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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