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Affiliation(s)
- Paul Munson
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
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In Silico Model Estimates the Clinical Trial Outcome of Cancer Vaccines. Cells 2021; 10:cells10113048. [PMID: 34831269 PMCID: PMC8616443 DOI: 10.3390/cells10113048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/27/2021] [Accepted: 11/03/2021] [Indexed: 12/22/2022] Open
Abstract
Over 30 years after the first cancer vaccine clinical trial (CT), scientists still search the missing link between immunogenicity and clinical responses. A predictor able to estimate the outcome of cancer vaccine CTs would greatly benefit vaccine development. Published results of 94 CTs with 64 therapeutic vaccines were collected. We found that preselection of CT subjects based on a single matching HLA allele does not increase immune response rates (IRR) compared with non-preselected CTs (median 60% vs. 57%, p = 0.4490). A representative in silico model population (MP) comprising HLA-genotyped subjects was used to retrospectively calculate in silico IRRs of CTs based on the percentage of MP-subjects having epitope(s) predicted to bind ≥ 1–4 autologous HLA allele(s). We found that in vitro measured IRRs correlated with the frequency of predicted multiple autologous allele-binding epitopes (AUC 0.63–0.79). Subgroup analysis of multi-antigen targeting vaccine CTs revealed correlation between clinical response rates (CRRs) and predicted multi-epitope IRRs when HLA threshold was ≥ 3 (r = 0.7463, p = 0.0004) but not for single HLA allele-binding epitopes (r = 0.2865, p = 0.2491). Our results suggest that CRR depends on the induction of broad T-cell responses and both IRR and CRR can be predicted when epitopes binding to multiple autologous HLAs are considered.
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Lau JS, Smith MZ, Lewin SR, McMahon JH. Clinical trials of antiretroviral treatment interruption in HIV-infected individuals. AIDS 2019; 33:773-791. [PMID: 30883388 DOI: 10.1097/qad.0000000000002113] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
: Despite the benefits of antiretroviral therapy (ART) for people living with HIV, there has been a long-standing research interest in interrupting ART as a strategy to minimize adverse effects of ART as well as to test interventions aiming to achieve a degree of virological control without ART. We performed a systematic review of HIV clinical studies involving treatment interruption from 2000 to 2017 to describe the differences between treatment interruption in studies that contained and didn't contain an intervention. We assessed differences in monitoring strategies, threshold to restart ART, duration and adverse outcomes of treatment interruption, and factors aimed at minimizing transmission. We found that treatment interruption has been incorporated into 159 clinical studies since 2000 and is increasingly being included in trials to assess the efficacy of interventions to achieve sustained virological remission off ART. Great heterogeneity was noted in immunological, virological and clinical monitoring strategies, as well as in thresholds to recommence ART. Treatment interruption in recent intervention studies were more closely monitored, had more conservative thresholds to restart ART and had a shorter treatment interruption duration, compared with older treatment interruption studies that didn't include an intervention.
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Perreau M, Banga R, Pantaleo G. Targeted Immune Interventions for an HIV-1 Cure. Trends Mol Med 2017; 23:945-961. [DOI: 10.1016/j.molmed.2017.08.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/09/2017] [Accepted: 08/14/2017] [Indexed: 01/13/2023]
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Graziani GM, Angel JB. Evaluating the efficacy of therapeutic HIV vaccines through analytical treatment interruptions. J Int AIDS Soc 2015; 18:20497. [PMID: 26561337 PMCID: PMC4641978 DOI: 10.7448/ias.18.1.20497] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/16/2015] [Accepted: 10/08/2015] [Indexed: 02/08/2023] Open
Abstract
INTRODUCTION The development of an effective therapeutic HIV vaccine that induces immunologic control of viral replication, thereby eliminating or reducing the need for antiretroviral therapy (ART), would be of great value. Besides the obvious challenges of developing a therapeutic vaccine that would generate effective, sustained anti-HIV immunity in infected individuals is the issue of how to best assess the efficacy of vaccine candidates. DISCUSSION This review discusses the various outcome measures assessed in therapeutic HIV vaccine clinical trials involving individuals receiving suppressive ART, with a particular focus on the role of analytical treatment interruption (ATI) as a way to assess the virologic control induced by an immunotherapy. This strategy is critical given that there are otherwise no readily available measures to determine the ability of a vaccine-induced immune response to effectively control HIV replication. The various outcome measures that have been used to assess vaccine efficacy in published therapeutic HIV vaccine clinical trials will also be discussed. Outcome measures have included the kinetics of viral rebound, the new viral set point and changes in the size of the viral reservoir. Clinically relevant outcomes such as the CD4 decline, the time to resume therapy or the time to meet the criterion to resume therapy, the proportion of participants who resume therapy and/or the development of clinical symptoms such as acute retroviral syndrome are also measures of vaccine efficacy. CONCLUSIONS Given the lack of consistency between therapeutic HIV vaccine trials in how efficacy is assessed, comparing vaccines has been difficult. It would, therefore, be beneficial to determine the most clinically relevant measure for use in future studies. Other recommendations for future clinical trials also include studying compartments in addition to blood and replacing ATIs with single-copy assays in situations in which the use of an ATI is not ideal.
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Affiliation(s)
| | - Jonathan B Angel
- Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Division of Infectious Disease, The Ottawa Hospital, Ottawa, ON, Canada;
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Klein N, Palma P, Luzuriaga K, Pahwa S, Nastouli E, Gibb DM, Rojo P, Borkowsky W, Bernardi S, Zangari P, Calvez V, Compagnucci A, Wahren B, Foster C, Munoz-Fernández MÁ, De Rossi A, Ananworanich J, Pillay D, Giaquinto C, Rossi P. Early antiretroviral therapy in children perinatally infected with HIV: a unique opportunity to implement immunotherapeutic approaches to prolong viral remission. THE LANCET. INFECTIOUS DISEASES 2015; 15:1108-1114. [PMID: 26187030 DOI: 10.1016/s1473-3099(15)00052-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 05/04/2015] [Accepted: 05/08/2015] [Indexed: 02/02/2023]
Abstract
From the use of antiretroviral therapy to prevent mother-to-child transmission to the possibility of HIV cure hinted at by the Mississippi baby experience, paediatric HIV infection has been pivotal to our understanding of HIV pathogenesis and management. Daily medication and indefinite antiretroviral therapy is recommended for children infected with HIV. Maintenance of life-long adherence is difficult and the incidence of triple-class virological failure after initiation of antiretroviral therapy increases with time. This challenge shows the urgent need to define novel strategies to provide long-term viral suppression that will allow safe interruption of antiretroviral therapy without viral rebound and any associated complications. HIV-infected babies treated within a few days of birth have a unique combination of a very small pool of integrated viruses, a very high proportion of relatively HIV resistant naive T cells, and an unparalleled capacity to regenerate an immune repertoire. These features make this group the optimum model population to investigate the potential efficacy of immune-based therapies. If successful, these investigations could change the way we manage HIV infection.
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Affiliation(s)
- Nigel Klein
- Institute of Child Health, University College London, London, UK.
| | - Paolo Palma
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital Bambino Gesù, Rome, Italy
| | - Katherine Luzuriaga
- Program in Molecular Medicine, University of Massachusetts Medical School Worcester, MA, USA
| | - Savita Pahwa
- Miami Center for AIDS Research Department of Microbiology and Immunology, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Eleni Nastouli
- Department of Virology, University College London, London, UK
| | - Diane M Gibb
- Medical Research Council Clinical Trials Unit, London, UK
| | - Pablo Rojo
- Department of Pediatrics, Hospital 12 de Octubre, Madrid, Spain
| | | | - Stefania Bernardi
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital Bambino Gesù, Rome, Italy
| | - Paola Zangari
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital Bambino Gesù, Rome, Italy
| | - Vincent Calvez
- Pierre et Marie Curie University and Pitié-Salpêtrière Hospital, Paris, France
| | - Alexandra Compagnucci
- Institut National de la Santé et de la Recherche Médicale SC10-US019 Clinical Trials and Infectious Diseases, Villejuif, Paris, France
| | - Britta Wahren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Caroline Foster
- Imperial College Healthcare National Health Service Trust, London, UK
| | | | - Anita De Rossi
- Section of Oncology and Immunology, Department of Surgery, Oncology and Gastroenterology-DiSCOG, University of Padova, and Istituto Oncologico Veneto, Padova, Italy
| | - Jintanat Ananworanich
- US Military HIV Research Program, Walter Reed Army Institute of Research and Henry M Jackson Foundation for the Advancement of Military Medicine, Silver Spring, MD, USA
| | - Deenan Pillay
- Africa Centre, Mtubatuba, KwaZulu Natal, South Africa
| | - Carlo Giaquinto
- Department of Women's and Children's Health, University of Padova, and Penta Foundation, Padova, Italy
| | - Paolo Rossi
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital Bambino Gesù, Rome, Italy.
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The EPIICAL project: an emerging global collaboration to investigate immunotherapeutic strategies in HIV-infected children. J Virus Erad 2015. [DOI: 10.1016/s2055-6640(20)30510-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Imami N, Herasimtschuk AA. Multifarious immunotherapeutic approaches to cure HIV-1 infection. Hum Vaccin Immunother 2015; 11:2287-93. [PMID: 26048144 PMCID: PMC4635699 DOI: 10.1080/21645515.2015.1021523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 02/15/2015] [Indexed: 01/19/2023] Open
Abstract
Immunotherapy in the context of treated HIV-1 infection aims to improve immune responses to achieve better control of the virus. To date, multifaceted immunotherapeutic approaches have been shown to reduce immune activation and increase CD4 T-lymphocyte counts, further to the effects of antiretroviral therapy alone, in addition to improving HIV-1-specific T-cell responses. While sterilizing cure of HIV-1 would involve elimination of all replication-competent virus, a functional cure in which the host has long-lasting control of viral replication may be more feasible. In this commentary, we discuss novel strategies aimed at targeting the latent viral reservoir with cure of HIV-1 infection being the ultimate goal, an achievement that would have considerable impact on worldwide HIV-1 infection.
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Affiliation(s)
- Nesrina Imami
- Department of Medicine; Imperial College London; London, UK
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9
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Herasimtschuk A, Downey J, Nelson M, Moyle G, Mandalia S, Sikut R, Adojaan M, Stanescu I, Gotch F, Imami N. Therapeutic immunisation plus cytokine and hormone therapy improves CD4 T-cell counts, restores anti-HIV-1 responses and reduces immune activation in treated chronic HIV-1 infection. Vaccine 2014; 32:7005-7013. [PMID: 25454870 DOI: 10.1016/j.vaccine.2014.09.072] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 08/04/2014] [Accepted: 09/08/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND This randomised, open label, phase I, immunotherapeutic study investigated the effects of interleukin (IL)-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), recombinant human growth hormone (rhGH), and therapeutic immunisation (a Clade B DNA vaccine) on combination antiretroviral therapy (cART)-treated HIV-1-infected individuals, with the objective to reverse residual T-cell dysfunction. METHODS Twelve HIV-1(+) patients on suppressive cART with baseline CD4 T-cell counts >400 cells/mm(3) blood were randomised into one of three groups: (1) vaccine, IL-2, GM-CSF and rhGH (n=3); (2) vaccine alone (n=4); or (3) IL-2, GM-CSF and rhGH (n=5). Samples were collected at weeks 0, 1, 2, 4, 6, 8, 12, 16, 24 and 48. Interferon (IFN)-γ, IL-2, IL-4 and perforin ELISpot assays performed at each time point quantified functional responses to Gag p17/p24, Nef, Rev, and Tat peptides; and detailed T-cell immunophenotyping was undertaken by flow cytometry. Proviral DNA was also measured. RESULTS Median baseline CD4 T-cell count was 757 cells/mm(3) (interquartile range [IQR] 567-886 cells/mm(3)), median age 48 years (IQR 42-51 years), and plasma HIV-1-RNA <50 copies/ml for all subjects. Patients who received vaccine plus IL-2, GM-CSF and rhGH (group 1) showed the most marked changes. Assessing mean changes from baseline to week 48 revealed significantly elevated numbers of CD4 T cells (p=0.0083) and improved CD4/CD8 T-cell ratios (p=0.0033). This was accompanied by a significant reduction in expression of CD38 on CD4 T cells (p=0.0194), significantly increased IFN-γ and IL-2 production in response to Gag (p=0.0122) and elevated IFN-γ production in response to Tat (p=0.041) at week 48 compared to baseline. Subjects in all treatment groups showed significantly reduced PD-1 expression at week 48 compared to baseline, with some reductions in proviral DNA. CONCLUSIONS Multifarious immunotherapeutic approaches in the context of fully suppressive cART further reduce immune activation, and improve both CD4 T-lymphocyte counts and HIV-1-specific T-cell responses (NCT01130376).
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Affiliation(s)
| | | | - Mark Nelson
- Chelsea and Westminster Hospital, London, UK
| | | | - Sundhiya Mandalia
- Imperial College London, London, UK; Chelsea and Westminster Hospital, London, UK
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Immunotherapy with an HIV-DNA Vaccine in Children and Adults. Vaccines (Basel) 2014; 2:563-80. [PMID: 26344746 PMCID: PMC4494215 DOI: 10.3390/vaccines2030563] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 11/17/2022] Open
Abstract
Therapeutic HIV immunization is intended to induce new HIV-specific cellular immune responses and to reduce viral load, possibly permitting extended periods without antiretroviral drugs. A multigene, multi-subtype A, B, C HIV-DNA vaccine (HIVIS) has been used in clinical trials in both children and adults with the aim of improving and broadening the infected individuals' immune responses. Despite the different country locations, different regimens and the necessary variations in assays performed, this is, to our knowledge, the first attempt to compare children's and adults' responses to a particular HIV vaccine. Ten vertically HIV-infected children aged 4-16 years were immunized during antiretroviral therapy (ART). Another ten children were blindly recruited as controls. Both groups continued their antiretroviral treatment during and after vaccinations. Twelve chronically HIV-infected adults were vaccinated, followed by repeated structured therapy interruptions (STI) of their antiretroviral treatment. The adult group included four controls, receiving placebo vaccinations. The HIV-DNA vaccine was generally well tolerated, and no serious adverse events were registered in any group. In the HIV-infected children, an increased specific immune response to Gag and RT proteins was detected by antigen-specific lymphoproliferation. Moreover, the frequency of HIV-specific CD8+ T-cell lymphocytes releasing perforin was significantly higher in the vaccinees than the controls. In the HIV-infected adults, increased CD8+ T-cell responses to Gag, RT and viral protease peptides were detected. No augmentation of HIV-specific lymphoproliferative responses were detected in adults after vaccination. In conclusion, the HIV-DNA vaccine can elicit new HIV-specific cellular immune responses, particularly to Gag antigens, in both HIV-infected children and adults. Vaccinated children mounted transient new HIV-specific immune responses, including both CD4+ T-cell lymphoproliferation and late CD8+ T-cell responses. In the adult cohort, primarily CD8+ T-cell responses related to MHC class I alleles were noted. However, no clinical benefits with respect to viral load reduction were ascribable to the vaccinations alone. No severe adverse effects related to the vaccine were found in either cohort, and no virological failures or drug resistances were detected.
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11
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Pollard RB, Rockstroh JK, Pantaleo G, Asmuth DM, Peters B, Lazzarin A, Garcia F, Ellefsen K, Podzamczer D, van Lunzen J, Arastéh K, Schürmann D, Clotet B, Hardy WD, Mitsuyasu R, Moyle G, Plettenberg A, Fisher M, Fätkenheuer G, Fischl M, Taiwo B, Baksaas I, Jolliffe D, Persson S, Jelmert O, Hovden AO, Sommerfelt MA, Wendel-Hansen V, Sørensen B. Safety and efficacy of the peptide-based therapeutic vaccine for HIV-1, Vacc-4x: a phase 2 randomised, double-blind, placebo-controlled trial. THE LANCET. INFECTIOUS DISEASES 2014; 14:291-300. [PMID: 24525316 DOI: 10.1016/s1473-3099(13)70343-8] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Present combination antiretroviral therapy (cART) alone does not cure HIV infection and requires lifelong drug treatment. The potential role of HIV therapeutic vaccines as part of an HIV cure is under consideration. Our aim was to assess the efficacy, safety, and immunogenicity of Vacc-4x, a peptide-based HIV-1 therapeutic vaccine targeting conserved domains on p24(Gag), in adults infected with HIV-1. METHODS Between July, 2008, and June, 2010, we did a multinational double-blind, randomised, phase 2 study comparing Vacc-4x with placebo. Participants were adults infected with HIV-1 who were aged 18-55 years and virologically suppressed on cART (viral load <50 copies per mL) with CD4 cell counts of 400 × 10(6) cells per L or greater. The trial was done at 18 sites in Germany, Italy, Spain, the UK, and the USA. Participants were randomly assigned (2:1) to Vacc-4x or placebo. Group allocation was masked from participants and investigators. Four primary immunisations, weekly for 4 weeks, containing Vacc-4x (or placebo) were given intradermally after administration of adjuvant. Booster immunisations were given at weeks 16 and 18. At week 28, cART was interrupted for up to 24 weeks. The coprimary endpoints were cART resumption and changes in CD4 counts during treatment interruption. Analyses were by modified intention to treat: all participants who received one intervention. Furthermore, safety, viral load, and immunogenicity (as measured by ELISPOT and proliferation assays) were assessed. The 52 week follow-up period was completed in June, 2011. For the coprimary endpoints the proportion of participants who met the criteria for cART resumption was analysed with a logistic regression model with the treatment effect being assessed in a model including country as a covariate. This study is registered with ClinicalTrials.gov, number NCT00659789. FINDINGS 174 individuals were screened; because of slow recruitment, enrolment stopped with 136 of a planned 345 participants and 93 were randomly assigned to receive Vacc-4x and 43 to receive placebo. There were no differences between the two groups for the primary efficacy endpoints in those participants who stopped cART at week 28. Of the participants who resumed cART, 30 (34%) were in the Vacc-4x group and 11 (29%) in the placebo group, and percentage changes in CD4 counts were not significant (mean treatment difference -5·71, 95% CI -13·01 to 1·59). However, a significant difference in viral load was noted for the Vacc-4x group both at week 48 (median 23,100 copies per mL Vacc-4x vs 71,800 copies per mL placebo; p=0·025) and week 52 (median 19,550 copies per mL vs 51,000 copies per mL; p=0·041). One serious adverse event, exacerbation of multiple sclerosis, was reported as possibly related to study treatment. Vacc-4x was immunogenic, inducing proliferative responses in both CD4 and CD8 T-cell populations. INTERPRETATION The proportion of participants resuming cART before end of study and change in CD4 counts during the treatment interruption showed no benefit of vaccination. Vacc-4x was safe, well tolerated, immunogenic, seemed to contribute to a viral-load setpoint reduction after cART interruption, and might be worth consideration in future HIV-cure investigative strategies. FUNDING Norwegian Research Council GLOBVAC Program and Bionor Pharma ASA.
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Affiliation(s)
- Richard B Pollard
- Division of Infectious Diseases, UC Davis Medical Center, Sacramento, CA, USA
| | - Jürgen K Rockstroh
- Universitätsklinikum Bonn, Medizinische Klinik und Poliklinik I, Immunologische Ambulanz, Bonn, Germany
| | - Giuseppe Pantaleo
- Division of Immunology and Allergy, Lausanne University Hospital, Lausanne, Switzerland
| | - David M Asmuth
- Division of Infectious Diseases, UC Davis Medical Center, Sacramento, CA, USA
| | | | - Adriano Lazzarin
- Department of Infectious Diseases, Ospedale San Raffaele and Vita-Salute University, Milan, Italy
| | - Felipe Garcia
- Infectious Diseases and AIDS Units, Hospital Clinic/IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Kim Ellefsen
- Division of Immunology and Allergy, Lausanne University Hospital, Lausanne, Switzerland
| | - Daniel Podzamczer
- HIV Unit, Infectious Disease Service, Hospital Universitari de Bellvitge, Barcelona, Spain
| | - Jan van Lunzen
- Universitätsklinikum Hamburg Eppendorf, Ambulanzzentrum Infektiologie, Hamburg, Germany
| | - Keikawus Arastéh
- EPIMED-Gesellschaft für Epidemiologische und Klinische Forschung in der Medizin mbH/Vivantes Auguste-Viktoria-Klinikum, Berlin, Germany
| | - Dirk Schürmann
- Department of Internal Medicine, Division of Infectious Diseases and Pulmonary Medicine, Charité-University Medicine Berlin, Berlin, Germany
| | - Bonaventura Clotet
- Irsicaixa Foundation, UAB, UVic, Hospital Universitari "Germans Trias i Pujol", Badalona, Catalonia, Spain
| | - W David Hardy
- Division of Infectious Diseases Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ronald Mitsuyasu
- UCLA CARE Center, University of California, Los Angeles, CA, USA
| | - Graeme Moyle
- Kobler Clinic, Chelsea and Westminster Hospital, London, UK
| | | | - Martin Fisher
- Brighton and Sussex University Hospital, HIV/GUM Research, Elton John Centre, Brighton, UK
| | - Gerd Fätkenheuer
- Klinik I für Innere Medizin, Klinikum der Universität zu Köln, Cologne, Germany
| | - Margaret Fischl
- University of Miami School of Medicine AIDS Clinical Research Unit, Miami, FL, USA
| | - Babafemi Taiwo
- Division of Infectious Diseases, Northwestern University, Chicago, IL, USA
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Palma P, Romiti ML, Montesano C, Santilli V, Mora N, Aquilani A, Dispinseri S, Tchidjou HK, Montano M, Eriksson LE, Baldassari S, Bernardi S, Scarlatti G, Wahren B, Rossi P. Therapeutic DNA vaccination of vertically HIV-infected children: report of the first pediatric randomised trial (PEDVAC). PLoS One 2013; 8:e79957. [PMID: 24312194 PMCID: PMC3842924 DOI: 10.1371/journal.pone.0079957] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 09/26/2013] [Indexed: 01/09/2023] Open
Abstract
Subjects Twenty vertically HIV-infected children, 6–16 years of age, with stable viral load control and CD4+ values above 400 cells/mm3. Intervention Ten subjects continued their ongoing antiretroviral treatment (ART, Group A) and 10 were immunized with a HIV-DNA vaccine in addition to their previous therapy (ART and vaccine, Group B). The genetic vaccine represented HIV-1 subtypes A, B and C, encoded Env, Rev, Gag and RT and had no additional adjuvant. Immunizations took place at weeks 0, 4 and 12, with a boosting dose at week 36. Monitoring was performed until week 60 and extended to week 96. Results Safety data showed good tolerance of the vaccine. Adherence to ART remained high and persistent during the study and did not differ significantly between controls and vaccinees. Neither group experienced either virological failure or a decline of CD4+ counts from baseline. Higher HIV-specific cellular immune responses were noted transiently to Gag but not to other components of the vaccine. Lymphoproliferative responses to a virion antigen HIV-1 MN were higher in the vaccinees than in the controls (p = 0.047), whereas differences in reactivity to clade-specific Gag p24, RT or Env did not reach significance. Compared to baseline, the percentage of HIV-specific CD8+ lymphocytes releasing perforin in the Group B was higher after the vaccination schedule had been completed (p = 0.031). No increased CD8+ perforin levels were observed in control Group A. Conclusions The present study demonstrates the feasibility, safety and moderate immunogenicity of genetic vaccination in vertically HIV-infected children, paving the way for amplified immunotherapeutic approaches in the pediatric population. Trial registration clinicaltrialsregister.eu _2007-002359-18IT
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Affiliation(s)
- Paolo Palma
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital “Bambino Gesu”, Rome, Italy
- * E-mail:
| | - Maria Luisa Romiti
- Department of Medicine, Chair of Pediatrics, University of Rome “Tor Vergata”, Rome, Italy
| | - Carla Montesano
- Department of Biology, University of Rome “Tor Vergata”, Rome, Italy
| | - Veronica Santilli
- Department of Medicine, Chair of Pediatrics, University of Rome “Tor Vergata”, Rome, Italy
| | - Nadia Mora
- Department of Medicine, Chair of Pediatrics, University of Rome “Tor Vergata”, Rome, Italy
| | - Angela Aquilani
- Department of Medicine, Chair of Pediatrics, University of Rome “Tor Vergata”, Rome, Italy
| | - Stefania Dispinseri
- Unit of Viral Evolution and Transmission, San Raffaele Scientific Institute, Milan, Italy
| | - Hyppolite K. Tchidjou
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital “Bambino Gesu”, Rome, Italy
| | - Marco Montano
- Chair of Infectious Diseases, University of Rome “Tor Vergata”, Rome, Italy
| | - Lars E. Eriksson
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet and Department of Infectious Diseases, Karolinska University Hospital, Huddinge, Sweden
- School of Health Science, City University, London, United Kingdom
| | - Stefania Baldassari
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital “Bambino Gesu”, Rome, Italy
| | - Stefania Bernardi
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital “Bambino Gesu”, Rome, Italy
| | - Gabriella Scarlatti
- Unit of Viral Evolution and Transmission, San Raffaele Scientific Institute, Milan, Italy
| | - Britta Wahren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Paolo Rossi
- University Department of Pediatrics, Unit of Immune and Infectious Diseases, Children's Hospital “Bambino Gesu”, Rome, Italy
- Department of Medicine, Chair of Pediatrics, University of Rome “Tor Vergata”, Rome, Italy
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Abstract
PURPOSE OF REVIEW As we enter the fourth decade in HIV epidemic, advances in understanding HIV pathogenesis and development of potent and safer antiretroviral drugs have been spectacular. More than 30 antiviral drugs have been registered and the impact of combination antiviral therapy on morbidity and mortality has been dramatic. However, despite long-term virus suppression, HIV invariably rebounds after interruption of therapy. Long-term antiviral therapy does not cure HIV infection nor does it induce restoration/development of virus-specific immune responses capable of controlling HIV replication. Therefore, development of immune-based interventions is needed to restore effective defenses that can lead to HIV functional cure and ultimately eradication. RECENT FINDINGS Therapeutic vaccination and immune interventions that generate de-novo or that boost preexisting HIV-specific T-cell responses are being investigated as a potential means to achieve a 'functional HIV cure'. One major hurdle in the quest of an HIV cure is control and elimination of the HIV latent reservoir. Several immune interventions that target the latent reservoir have been tried in recent years. In parallel, several therapeutic vaccination strategies have been developed and tested in early clinical studies. Recent encouraging studies show for the first time that vaccination can have an impact on HIV load. SUMMARY This review summarizes the main immune interventions evaluated over the last years. Ways to improve them, as well as challenges in monitoring/evaluating effects of such strategies, are being discussed. In addition, clinical efficacy and potential clinical benefits of immunotherapeutic interventions are particularly difficult to measure. This review highlights current assays used and their shortcoming.
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Hallengärd D, Wahren B, Bråve A. A truncated plasmid-encoded HIV-1 reverse transcriptase displays strong immunogenicity. Viral Immunol 2013; 26:163-6. [PMID: 23573980 DOI: 10.1089/vim.2012.0083] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Besides being an important target in the antiretroviral therapy against the human immunodeficiency virus type 1 (HIV-1), the HIV-1 reverse transcriptase (RT) enzyme has potential as a vaccine antigen. In this study, we explored the ability of plasmid-encoded RT to induce cell-mediated immune responses. The strategy for increasing the immunogenicity of the protein was to delete non- or low-immunogenic parts in order to focus the immune responses to known immunogenic regions. Expression and immunogenicity of the truncated RT was compared to a clinically evaluated full-length RT construct, and the truncated RT displayed enhanced in vitro expression and cell-mediated immune responses in BALB/c and HLA-A0201 transgenic C57BL/6 mice. The strong immune responses were retained also when the truncated RT was delivered as a part of a multigene HIV-1 vaccine. Linking the RT gene to a highly expressed HIV-1 protease gene did not increase the immunogenicity of RT. This optimization strategy could be used to enhance the immunogenicity of other RT-encoding DNA vaccines.
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Affiliation(s)
- David Hallengärd
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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15
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Optimization of HIV-1 Envelope DNA Vaccine Candidates within Three Different Animal Models, Guinea Pigs, Rabbits and Cynomolgus Macaques. Vaccines (Basel) 2013; 1:305-27. [PMID: 26344115 PMCID: PMC4494233 DOI: 10.3390/vaccines1030305] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 07/05/2013] [Accepted: 07/10/2013] [Indexed: 11/17/2022] Open
Abstract
HIV-1 DNA vaccines have many advantageous features. Evaluation of HIV-1 vaccine candidates often starts in small animal models before macaque and human trials. Here, we selected and optimized DNA vaccine candidates through systematic testing in rabbits for the induction of broadly neutralizing antibodies (bNAb). We compared three different animal models: guinea pigs, rabbits and cynomolgus macaques. Envelope genes from the prototype isolate HIV-1 Bx08 and two elite neutralizers were included. Codon-optimized genes, encoded secreted gp140 or membrane bound gp150, were modified for expression of stabilized soluble trimer gene products, and delivered individually or mixed. Specific IgG after repeated i.d. inoculations with electroporation confirmed in vivo expression and immunogenicity. Evaluations of rabbits and guinea pigs displayed similar results. The superior DNA construct in rabbits was a trivalent mix of non-modified codon-optimized gp140 envelope genes. Despite NAb responses with some potency and breadth in guinea pigs and rabbits, the DNA vaccinated macaques displayed less bNAb activity. It was concluded that a trivalent mix of non-modified gp140 genes from rationally selected clinical isolates was, in this study, the best option to induce high and broad NAb in the rabbit model, but this optimization does not directly translate into similar responses in cynomolgus macaques.
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16
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Abstract
Dendritic cells (DCs) are a diverse subset of innate immune cells that are key regulators of the host response to human immunodeficiency virus-1 (HIV-1) infection. HIV-1 directly and indirectly modulates DC function to hinder the formation of effective antiviral immunity and fuel immune activation. This review focuses upon the differential dysregulation of myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) at various stages of HIV-1 infection providing insights into pathogenesis. HIV-1 evades innate immune sensing by mDCs resulting in suboptimal maturation, lending to poor generation of antiviral adaptive responses and contributing to T-regulatory cell (Treg) development. Dependent upon the stage of HIV-1 infection, mDC function is altered in response to Toll-like receptor ligands, which further hinders adaptive immunity and limits feasibility of therapeutic vaccine strategies. pDC interactions with HIV-1 are pleotropic, modulating immune responses on an axis between immunostimulatory and immunosuppressive. pDCs promote immune activation through an altered phenotype of persistent type I interferon secretion and weak antigen presentation capacity. Conversely, HIV-1 stimulates secretion of indolemine 2,3 dioxygenase (IDO) by pDCs resulting in Treg induction. An improved understanding of the roles and underlying mechanisms of DC dysfunction will be valuable to the development of therapeutics to enhance HIV-specific adaptive responses and to dampen immune activation.
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Affiliation(s)
- Elizabeth Miller
- Division of Infectious Diseases, New York University School of Medicine, New York, NY, USA
| | - Nina Bhardwaj
- Cancer Institute, New York University School of Medicine, New York, NY, USA
- Division of Hematology and Oncology, Mount Sinai Medical Center, New York, NY, USA
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17
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Mittal A, Raber AS, Lehr CM, Hansen S. Particle based vaccine formulations for transcutaneous immunization. Hum Vaccin Immunother 2013; 9:1950-5. [PMID: 23778884 DOI: 10.4161/hv.25217] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Vaccine formulations on the basis of nano- (NP) or microparticles (MP) can solve issues with stabilization, controlled release, and poor immunogenicity of antigens. Likewise transcutaneous immunization (TCI) promises superior immunogenicity as well as the advantages of needle-free application compared with conventional intramuscular injections. Thus the combination of both strategies seems to be a very valuable approach. However, until now TCI using particle based vaccine formulations has made no impact on medical practice. One of the main difficulties is that NPs and MPs cannot penetrate the skin to an extent that would allow the application of the required dose of antigen. This is due to the formidable stratum corneum (SC) barrier, the limited amount of antigen in the formulation and often an insufficient immunogenicity. A multitude of strategies are currently under investigation to overcome these issues. We highlight selected methods presenting a spectrum of solutions ranging from transfollicular delivery, to devices disrupting the SC barrier and the combination of particle based vaccines with adjuvants discussing their advantages and shortcomings. Some of these are currently at an experimental state while others are already in clinical testing. All methods have been shown to be capable of transcutaneous antigen delivery.
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Affiliation(s)
- Ankit Mittal
- Biopharmaceutics and Pharmaceutical Technology; Saarland University; Saarbruecken, Germany
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18
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Nowroozalizadeh S, Gudmundsdotter L, Hejdeman B, Andersson L, Esbjörnsson J, Medstrand P, Sandström E, Gaines H, Wahren B, Jansson M. Short-term HIV-1 treatment interruption is associated with dysregulated TLR-stimuli responsiveness. Hum Vaccin Immunother 2013; 9:2103-10. [PMID: 23912942 DOI: 10.4161/hv.25154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Viremia during human immunodeficiency virus type-1 (HIV-1) infection results in progressive impairment of several components of the immune system. Here a unique model of repeated treatment interruptions (TIs) was used with the aim to reveal the effect of controlled short-term viremia on innate stimuli responsiveness and circulating dendritic cells (DCs). Sequential peripheral blood samples from HIV-1-infected patients on combination antiretroviral therapy, subjected to repeated TI cycles as part of a therapeutic DNA vaccination study, were analyzed. In vitro responsiveness of peripheral blood mononuclear cells to toll-like receptor (TLR) stimuli was analyzed by cytokine secretion, and frequencies of plasmacytoid DCs (pDCs) and myeloid DCs (mDCs) were monitored by flow cytometry. These parameters were found not to be significantly different between the vaccinated and placebo groups. Instead, independent of vaccination altered in vitro TLR responsiveness was observed in parallel with TI cycles. TLR7/8-triggered secretion of IL-12 and IFN-α, as well as TLR9-triggered secretion of IL-12, was hyperactivated. In contrast, expression of IFN-α after TLR9 stimulation decreased during the initial cycle of TI. Reduced frequencies of pDCs and mDCs, compared with baseline, were noted before and during the second TI, respectively. Furthermore, spontaneous ex vivo release of IL-12 from PBMC was noted during cycles of TI. In conclusion, these results suggest that consequences of short-term TI include dysregulated TLR responses and fluctuations in the frequencies of circulating DCs. Knowledge of these immunological factors may influence the continuation of stringent treatment schedules during HIV infections.
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Affiliation(s)
- Salma Nowroozalizadeh
- The Swedish Institute for Communicable Disease Control; Stockholm, Sweden; Department of Microbiology; Tumor and Cell Biology; Karolinska Institutet; Stockholm, Sweden
| | - Lindvi Gudmundsdotter
- The Swedish Institute for Communicable Disease Control; Stockholm, Sweden; Department of Microbiology; Tumor and Cell Biology; Karolinska Institutet; Stockholm, Sweden
| | - Bo Hejdeman
- Department of Infectious Diseases/Venhälsan; Stockholm South General Hospital; Stockholm, Sweden
| | - Lena Andersson
- The Swedish Institute for Communicable Disease Control; Stockholm, Sweden
| | | | - Patrik Medstrand
- Department of Laboratory Medicine Malmö; Lund University; Lund, Sweden
| | - Eric Sandström
- Department of Infectious Diseases/Venhälsan; Stockholm South General Hospital; Stockholm, Sweden
| | - Hans Gaines
- The Swedish Institute for Communicable Disease Control; Stockholm, Sweden
| | - Britta Wahren
- The Swedish Institute for Communicable Disease Control; Stockholm, Sweden; Department of Microbiology; Tumor and Cell Biology; Karolinska Institutet; Stockholm, Sweden
| | - Marianne Jansson
- Department of Microbiology; Tumor and Cell Biology; Karolinska Institutet; Stockholm, Sweden; Department of Laboratory Medicine Lund; Lund University; Lund, Sweden
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19
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Higa LH, Schilrreff P, Perez AP, Iriarte MA, Roncaglia DI, Morilla MJ, Romero EL. Ultradeformable archaeosomes as new topical adjuvants. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2012; 8:1319-28. [DOI: 10.1016/j.nano.2012.02.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 01/22/2012] [Accepted: 02/13/2012] [Indexed: 11/30/2022]
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20
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Vanham G, Van Gulck E. Can immunotherapy be useful as a "functional cure" for infection with Human Immunodeficiency Virus-1? Retrovirology 2012; 9:72. [PMID: 22958464 PMCID: PMC3472319 DOI: 10.1186/1742-4690-9-72] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 08/07/2012] [Indexed: 11/30/2022] Open
Abstract
Immunotherapy aims to assist the natural immune system in achieving control over viral infection. Various immunotherapy formats have been evaluated in either therapy-naive or therapy-experienced HIV-infected patients over the last 20 years. These formats included non-antigen specific strategies such as cytokines that stimulate immunity or suppress the viral replication, as well as antibodies that block negative regulatory pathways. A number of HIV-specific therapeutic vaccinations have also been proposed, using in vivo injection of inactivated virus, plasmid DNA encoding HIV antigens, or recombinant viral vectors containing HIV genes. A specific format of therapeutic vaccines consists of ex vivo loading of autologous dendritic cells with one of the above mentioned antigenic formats or mRNA encoding HIV antigens.This review provides an extensive overview of the background and rationale of these different therapeutic attempts and discusses the results of trials in the SIV macaque model and in patients. To date success has been limited, which could be explained by insufficient quality or strength of the induced immune responses, incomplete coverage of HIV variability and/or inappropriate immune activation, with ensuing increased susceptibility of target cells.Future attempts at therapeutic vaccination should ideally be performed under the protection of highly active antiretroviral drugs in patients with a recovered immune system. Risks for immune escape should be limited by a better coverage of the HIV variability, using either conserved or mosaic sequences. Appropriate molecular adjuvants should be included to enhance the quality and strength of the responses, without inducing inappropriate immune activation. Finally, to achieve a long-lasting effect on viral control (i.e. a "functional cure") it is likely that these immune interventions should be combined with anti-latency drugs and/or gene therapy.
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Affiliation(s)
- Guido Vanham
- Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine of Antwerp, Nationalestraat 155, B-2000, Antwerpen, Belgium
- Department of Biomedical Sciences, University of Antwerpen, Antwerpen, Belgium
| | - Ellen Van Gulck
- Virology Unit, Department of Biomedical Sciences, Institute of Tropical Medicine of Antwerp, Nationalestraat 155, B-2000, Antwerpen, Belgium
- Present address: Community of Research Excellence and Advanced Technology (C.R.E.A.Te), Division of Janssen, Beerse, Belgium
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21
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Dandekar P, Jain R, Keil M, Loretz B, Muijs L, Schneider M, Auerbach D, Jung G, Lehr CM, Wenz G. Cellular delivery of polynucleotides by cationic cyclodextrin polyrotaxanes. J Control Release 2012; 164:387-93. [PMID: 22789529 DOI: 10.1016/j.jconrel.2012.06.040] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 06/10/2012] [Accepted: 06/30/2012] [Indexed: 11/18/2022]
Abstract
Cationic polyrotaxanes, obtained by temperature activated threading of cationic cyclodextrin derivatives onto water-soluble cationic polymers (ionenes), form metastable nanometric polyplexes with pDNA and combinations of siRNA with pDNA. Because of their low toxicity, the polyrotaxane polyplexes constitute a very interesting system for the transfection of polynucleotides into mammalian cells. The complexation of Cy3-labeled siRNA within the polyplexes was demonstrated by fluorescence correlation spectroscopy. The uptake of the polyplexes (red) was imaged by confocal fluorescence microscopy using the A549 cell line as a model (blue: nuclei, green: membranes). The results prove the potential of polyrotaxanes for further investigations involving knocking down genes of therapeutic interest.
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Affiliation(s)
- Prajakta Dandekar
- Department of Drug Delivery, Helmholtz-Institute for Pharmaceutical Research Saarland, Helmholtz-Center for Infection Research (HZI), Saarland University, D-66123 Saarbrücken, Germany
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22
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García F, León A, Gatell JM, Plana M, Gallart T. Therapeutic vaccines against HIV infection. Hum Vaccin Immunother 2012; 8:569-81. [PMID: 22634436 DOI: 10.4161/hv.19555] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Resistance to medication, adverse effects in the medium-to-long-term and cost all place important limitations on lifelong adherence to combined antiretroviral therapy (cART). In this context, new therapeutic alternatives to 'cART for life' in HIV-infected patients merit investigation. Some data suggest that strong T cell-mediated immunity to HIV can indeed limit virus replication and protect against CD4 depletion and disease progression. The combination of cART with immune therapy to restore and/or boost immune-specific responses to HIV has been proposed, the ultimate aim being to achieve a 'functional cure'. In this scenario, new, induced, HIV-specific immune responses would be able to control viral replication to undetectable levels, mimicking the situation of the minority of patients who control viral replication without treatment and do not progress to AIDS. Classical approaches such as whole inactivated virus or recombinant protein initially proved useful as therapeutic vaccines. Overall, however, the ability of these early vaccines to increase HIV-specific responses was very limited and study results were discouraging, as no consistent immunogenicity was demonstrated and there was no clear impact on viral load. Recent years have seen the development of new approaches based on more innovative vectors such as DNA, recombinant virus or dendritic cells. Most clinical trials of these new vectors have demonstrated their ability to induce HIV-specific immune responses, although they show very limited efficacy in terms of controlling viral replication. However, some preliminary results suggest that dendritic cell-based vaccines are the most promising candidates. To improve the effectiveness of these vaccines, a better understanding of the mechanisms of protection, virological control and immune deterioration is required; without this knowledge, an efficacious therapeutic vaccine will remain elusive.
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Affiliation(s)
- Felipe García
- Hospital Clinic-HIVACAT, IDIBAPS, University of Barcelona, Barcelona, Spain.
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23
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Jäger M, Schubert S, Ochrimenko S, Fischer D, Schubert US. Branched and linear poly(ethylene imine)-based conjugates: synthetic modification, characterization, and application. Chem Soc Rev 2012; 41:4755-67. [DOI: 10.1039/c2cs35146c] [Citation(s) in RCA: 234] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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24
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Scholz C, Wagner E. Therapeutic plasmid DNA versus siRNA delivery: common and different tasks for synthetic carriers. J Control Release 2011; 161:554-65. [PMID: 22123560 DOI: 10.1016/j.jconrel.2011.11.014] [Citation(s) in RCA: 235] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/10/2011] [Accepted: 11/13/2011] [Indexed: 01/22/2023]
Abstract
Gene therapy offers great opportunities for the treatment of severe diseases including cancer. In recent years the design of synthetic carriers for nucleic acid delivery has become a research field of increasing interest. Studies on the delivery of plasmid DNA (pDNA) have brought up a variety of gene delivery vehicles. The more recently emerged gene silencing strategy by the intracellular delivery of small interfering RNA (siRNA) takes benefit from existing expertise in pDNA transfer. Despite common properties however, delivery of siRNA also faces distinct challenges due to apparent differences in size, stability of the formed nucleic acid complexes, the location and mechanism of action. This review emphasizes the common aspects and main differences between pDNA and siRNA delivery, taking into consideration a wide spectrum of polymer-based, lipidic and peptide carriers. Challenges and opportunities which result from these differences as well as the recent progress made in the optimization of carrier design are presented.
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Affiliation(s)
- Claudia Scholz
- Pharmaceutical Biotechnology, Center for System-based Drug Research, and Center for NanoScience, Ludwig-Maximilians-Universität, Butenandtstrasse 5-13, 81377 Munich, Germany
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25
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Abstract
The living epidermis and dermis are rich in antigen presenting cells (APCs). Their activation can elicit a strong humoral and cellular immune response as well as mucosal immunity. Therefore, the skin is a very attractive site for vaccination, and an intradermal application of antigen may be much more effective than a subcutaneous or intramuscular injection. However, the stratum corneum (SC) is a most effective barrier against the invasion of topically applied vaccines. Products which have reached the stage of clinical testing, avoid this problem by injecting the nano‐vaccine intradermally or by employing a barrier disrupting method and applying the vaccine to a relatively large skin area. Needle‐free vaccination is desirable from a number of aspects: ease of application, improved patient acceptance and less risk of infection among them. Nanocarriers can be designed in a way that they can overcome the SC. Also incorporation into nanocarriers protects instable antigen from degradation, improves uptake and processing by APCs, and facilitates endosomal escape and nuclear delivery of DNA vaccines. In addition, sustained release systems may build a depot in the tissue gradually releasing antigen which may avoid booster doses. Therefore, nanoformulations of vaccines for transcutaneous immunization are currently a very dynamic field of research. Among the huge variety of nanocarrier systems that are investigated hopes lie on ultra‐flexible liposomes, superfine rigid nanoparticles and nanocarriers, which are taken up by hair follicles. The potential and pitfalls associated with these three classes of carriers will be discussed.
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Affiliation(s)
- Steffi Hansen
- Department of Drug Delivery, Helmholtz-Institute for Pharmaceutical Research Saarland-HIPS, Helmholtz-Center for Infection Research-HZI, Saarbruecken, Germany.
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