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Warschkau D, Seeber F. Advances towards the complete in vitro life cycle of Toxoplasma gondii. Fac Rev 2023; 12:1. [PMID: 36846606 PMCID: PMC9944905 DOI: 10.12703/r/12-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
The full life cycle of Toxoplasma gondii cannot be recapitulated in vitro, and access to certain stages, such as mature tissue cysts (bradyzoites) and oocysts (sporozoites), traditionally requires animal experiments. This has greatly hindered the study of the biology of these morphologically and metabolically distinct stages, which are essential for the infection of humans and animals. However, several breakthrough advances have been made in recent years towards obtaining these life stages in vitro, such as the discovery of several molecular factors that induce differentiation and commitment to the sexual cycle, and different culture methods that use, for example, myotubes and intestinal organoids to obtain mature bradyzoites and different sexual stages of the parasite. We review these novel tools and approaches, highlight their limitations and challenges, and discuss what research questions can already be answered with these models. We finally identify future routes for recapitulating the entire sexual cycle in vitro.
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Affiliation(s)
- David Warschkau
- FG16: Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institut, Berlin, Germany
| | - Frank Seeber
- FG16: Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institut, Berlin, Germany
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Ong CY, Abdalkareem EA, Khoo BY. Functional roles of cytokines in infectious disease associated colorectal carcinogenesis. Mol Biol Rep 2022; 49:1529-1535. [PMID: 34981335 DOI: 10.1007/s11033-021-07006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 11/23/2021] [Indexed: 11/29/2022]
Abstract
Infection processes induce various soluble factors that are carcinogens in humans; therefore, research into the soluble factors of chronic disease released from cells that have been infected with parasites is warranted. Parasitic infections in host cells release high levels of IFNγ. Studies have hypothesised that parasitosis-associated carcinogenesis might be analogous to colorectal cancers developed from inflammatory bowel diseases, whereby various cytokines and chemokines are secreted during chronic inflammation. IL-18 and IL-21 are other factors that might be involved in the development of colorectal cancer in schistosomiasis patients and patients with other infections. IL-21 has profound effects on tumour growth and immunosurveillance of colitis-associated tumourigenesis, thereby emphasising its involvement in the pathogenesis of colorectal cancer. The prominent role of IL-21 in antitumour effects greatly depends on the enhanced cytolytic activity of NK cells and the pathogenic role of IL-21, which is often associated with enhanced risks of cancer and chronic inflammatory processes. As IL-15 is also related to chronic disease, it is believed to also play a role in the antitumour effect of colorectal carcinogenesis. IL-15 generates and maintains long-term CD8+ T cell immunity against T. gondii to control the infection of intracellular pathogens. The lack of IL-15 in mice contributes to the downregulation of the IFNγ-producing CD4+ T cell response against acute T. gondii infection. IL-15 induces hyperplasia and supports the progressive growth of colon cancer via multiple functions. The limited role of IL-15 in the development of NK and CD8+ T cells suggests that there may be other cytokines compensating for the loss of the IL-15 gene.
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Affiliation(s)
- Ching Yi Ong
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, H53, Jalan Inovasi, 11800, Gelugor, Penang, Malaysia
| | - Eshtiyag Abdalla Abdalkareem
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, H53, Jalan Inovasi, 11800, Gelugor, Penang, Malaysia.,Tropical Medicine Research Institute (TMRI), 1304, El-Gaser Street, Khartoum, Sudan
| | - Boon Yin Khoo
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, H53, Jalan Inovasi, 11800, Gelugor, Penang, Malaysia.
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Sana M, Rashid M, Rashid I, Akbar H, Gomez-Marin JE, Dimier-Poisson I. Immune response against toxoplasmosis-some recent updates RH: Toxoplasma gondii immune response. Int J Immunopathol Pharmacol 2022; 36:3946320221078436. [PMID: 35227108 PMCID: PMC8891885 DOI: 10.1177/03946320221078436] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AIMS Cytokines, soluble mediators of immunity, are key factors of the innate and adaptive immune system. They are secreted from and interact with various types of immune cells to manipulate host body's immune cell physiology for a counter-attack on the foreign body. A study was designed to explore the mechanism of Toxoplasma gondii (T. gondii) resistance from host immune response. METHODS AND RESULTS The published data on aspect of host (murine and human) immune response against T. gondii was taken from Google scholar and PubMed. Most relevant literature was included in this study. The basic mechanism of immune response starts from the interactions of antigens with host immune cells to trigger the production of cytokines (pro-inflammatory and anti-inflammatory) which then act by forming a cytokinome (network of cytokine). Their secretory equilibrium is essential for endowing resistance to the host against infectious diseases, particularly toxoplasmosis. A narrow balance lying between Th1, Th2, and Th17 cytokines (as demonstrated until now) is essential for the development of resistance against T. gondii as well as for the survival of host. Excessive production of pro-inflammatory cytokines leads to tissue damage resulting in the production of anti-inflammatory cytokines which enhances the proliferation of Toxoplasma. Stress and other infectious diseases (human immunodeficiency virus (HIV)) that weaken the host immunity particularly the cellular component, make the host susceptible to toxoplasmosis especially in pregnant women. CONCLUSION The current review findings state that in vitro harvesting of IL12 from DCs, Np and MΦ upon exposure with T. gondii might be a source for therapeutic use in toxoplasmosis. Current review also suggests that therapeutic interventions leading to up-regulation/supplementation of SOCS-3, IL12, and IFNγ to the infected host could be a solution to sterile immunity against T. gondii infection. This would be of interest particularly in patients passing through immunosuppression owing to any reason like the ones receiving anti-cancer therapy, the ones undergoing immunosuppressive therapy for graft/transplantation, the ones suffering from immunodeficiency virus (HIV) or having AIDS. Another imortant suggestion is to launch the efforts for a vaccine based on GRA6Nt or other similar antigens of T. gondii as a probable tool to destroy tissue cysts.
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Affiliation(s)
- Madiha Sana
- Department of Parasitology, 66920University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Muhammad Rashid
- Department of Parasitology, Faculty of Veterinary and Animal Sciences, 66920The Islamia University of Bahawalpur, Pakistan
| | - Imran Rashid
- Department of Parasitology, 66920University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Haroon Akbar
- Department of Parasitology, 66920University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Jorge E Gomez-Marin
- Grupo Gepamol, Centro de Investigaciones Biomedicas, Universidad del Quindio, Armenia, CO, South America
| | - Isabelle Dimier-Poisson
- Université de Tours, Institut national de recherche pour l'agriculture, l'alimentation et l'environnement (INRAE), Unité mixte de recherche 1282 (UMR1282), Infectiologie et santé publique (ISP), Tours, France
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Mukhopadhyay D, Arranz-Solís D, Saeij JPJ. Influence of the Host and Parasite Strain on the Immune Response During Toxoplasma Infection. Front Cell Infect Microbiol 2020; 10:580425. [PMID: 33178630 PMCID: PMC7593385 DOI: 10.3389/fcimb.2020.580425] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/11/2020] [Indexed: 01/02/2023] Open
Abstract
Toxoplasma gondii is an exceptionally successful parasite that infects a very broad host range, including humans, across the globe. The outcome of infection differs remarkably between hosts, ranging from acute death to sterile infection. These differential disease patterns are strongly influenced by both host- and parasite-specific genetic factors. In this review, we discuss how the clinical outcome of toxoplasmosis varies between hosts and the role of different immune genes and parasite virulence factors, with a special emphasis on Toxoplasma-induced ileitis and encephalitis.
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Affiliation(s)
- Debanjan Mukhopadhyay
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - David Arranz-Solís
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Jeroen P J Saeij
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
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Hong Y, Kim Y, Lee JJ, Lee MG, Lee CY, Kim Y, Heo J, Han SS, Lee SJ, Kim WJ, Hong JY. Levels of vitamin D-associated cytokines distinguish between active and latent tuberculosis following a tuberculosis outbreak. BMC Infect Dis 2019; 19:151. [PMID: 30760247 PMCID: PMC6375131 DOI: 10.1186/s12879-019-3798-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/08/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Vitamin D levels are associated with the extent of mycobactericidal activity. Interleukin (IL)-15 and IL-32 play roles in the vitamin D-mediated tuberculosis (TB) defense mechanism. Vitamin D induces IL-1β, which plays an important role in terms of resistance to TB. We evaluated whether the levels of vitamin D-related cytokines distinguished between those with active TB and latent TB infection (LTBI). METHODS In total, 50 TB-infected patients (25 with active TB and 25 with LTBI following a TB outbreak in a high school) were enrolled. Plasma 25-hydroxyvitamin D (25[OH]D), IL-15, IL-32, and IL-1β levels were measured via enzyme-linked immunosorbent assays. Mycobacterium tuberculosis-specific antigen-induced and unstimulated cytokine levels were measured in the supernatants of the QuantiFERON TB Gold-In-Tube (QFT-GIT) assay. RESULTS Plasma 25(OH)D and plasma IL-15 levels were lower in patients with active TB than in LTBI subjects (25(OH)D: 16.64 ng/mL vs. 21.6 ng/mL, P = 0.031; IL-15: 148.9 pg/mL vs. 189.8 pg/mL, P = 0.013). Plasma 25(OH)D levels correlated with the plasma levels of IL-15 and IL-1β in TB-infected patients. In addition, the plasma 25(OH)D levels correlated positively with the level of unstimulated IL-15 (IL-15nil) and negatively with that of TB antigen-stimulated IL-32 (IL-32TB) in QFT-GIT supernatants. Although the IL-15nil and IL-15TB levels were higher in LTBI subjects than patients with active TB, the IL-32nil and IL-32TB levels were higher in the latter patients. A combination of the IL-15nil and IL-32TB levels accurately predicted 91.3% of active TB patients and latent subjects, with an area under the curve of 0.964. CONCLUSIONS Our preliminary data showed that the levels of the vitamin D-related cytokines IL-15 and IL-32 differed between active TB patients and LTBI subjects. This result might be used as a basic data for developing biomarkers distinguishing between active TB and LTBI.
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Affiliation(s)
- Yoonki Hong
- Department of Internal Medicine, Kangwon National University Hospital, School of Medicine,Kangwon National University, Chuncheon, Republic of Korea
| | - Youngmi Kim
- Institute of New frontier Research, Hallym University College of Medicine, Chuncheon, South Korea
| | - Jae Jun Lee
- Institute of New frontier Research, Hallym University College of Medicine, Chuncheon, South Korea
| | - Myung Goo Lee
- Lung Research Institute of Hallym University College of Medicine, Chuncheon, Gangwon-do Republic of Korea
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University Medical Center, 77, Sakju-ro, Chuncheon-si, Gangwon-do 200-704 Republic of Korea
| | - Chang Youl Lee
- Lung Research Institute of Hallym University College of Medicine, Chuncheon, Gangwon-do Republic of Korea
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University Medical Center, 77, Sakju-ro, Chuncheon-si, Gangwon-do 200-704 Republic of Korea
| | - Youlim Kim
- Lung Research Institute of Hallym University College of Medicine, Chuncheon, Gangwon-do Republic of Korea
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University Medical Center, 77, Sakju-ro, Chuncheon-si, Gangwon-do 200-704 Republic of Korea
| | - Jeongwon Heo
- Department of Internal Medicine, Kangwon National University Hospital, School of Medicine,Kangwon National University, Chuncheon, Republic of Korea
| | - Seon-Sook Han
- Department of Internal Medicine, Kangwon National University Hospital, School of Medicine,Kangwon National University, Chuncheon, Republic of Korea
| | - Seung-Joon Lee
- Department of Internal Medicine, Kangwon National University Hospital, School of Medicine,Kangwon National University, Chuncheon, Republic of Korea
| | - Woo Jin Kim
- Department of Internal Medicine, Kangwon National University Hospital, School of Medicine,Kangwon National University, Chuncheon, Republic of Korea
| | - Ji Young Hong
- Lung Research Institute of Hallym University College of Medicine, Chuncheon, Gangwon-do Republic of Korea
- Institute of New frontier Research, Hallym University College of Medicine, Chuncheon, South Korea
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Chuncheon Sacred Heart Hospital, Hallym University Medical Center, 77, Sakju-ro, Chuncheon-si, Gangwon-do 200-704 Republic of Korea
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Suschak JJ, Williams JA, Schmaljohn CS. Advancements in DNA vaccine vectors, non-mechanical delivery methods, and molecular adjuvants to increase immunogenicity. Hum Vaccin Immunother 2017. [PMID: 28604157 DOI: 10.1080/21645515.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
Abstract
A major advantage of DNA vaccination is the ability to induce both humoral and cellular immune responses. DNA vaccines are currently used in veterinary medicine, but have not achieved widespread acceptance for use in humans due to their low immunogenicity in early clinical studies. However, recent clinical data have re-established the value of DNA vaccines, particularly in priming high-level antigen-specific antibody responses. Several approaches have been investigated for improving DNA vaccine efficacy, including advancements in DNA vaccine vector design, the inclusion of genetically engineered cytokine adjuvants, and novel non-mechanical delivery methods. These strategies have shown promise, resulting in augmented adaptive immune responses in not only mice, but also in large animal models. Here, we review advancements in each of these areas that show promise for increasing the immunogenicity of DNA vaccines.
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Affiliation(s)
- John J Suschak
- a U.S. Army Medical Research Institute of Infectious Diseases , Fort Detrick , MD , USA
| | | | - Connie S Schmaljohn
- a U.S. Army Medical Research Institute of Infectious Diseases , Fort Detrick , MD , USA
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Suschak JJ, Williams JA, Schmaljohn CS. Advancements in DNA vaccine vectors, non-mechanical delivery methods, and molecular adjuvants to increase immunogenicity. Hum Vaccin Immunother 2017; 13:2837-2848. [PMID: 28604157 PMCID: PMC5718814 DOI: 10.1080/21645515.2017.1330236] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
A major advantage of DNA vaccination is the ability to induce both humoral and cellular immune responses. DNA vaccines are currently used in veterinary medicine, but have not achieved widespread acceptance for use in humans due to their low immunogenicity in early clinical studies. However, recent clinical data have re-established the value of DNA vaccines, particularly in priming high-level antigen-specific antibody responses. Several approaches have been investigated for improving DNA vaccine efficacy, including advancements in DNA vaccine vector design, the inclusion of genetically engineered cytokine adjuvants, and novel non-mechanical delivery methods. These strategies have shown promise, resulting in augmented adaptive immune responses in not only mice, but also in large animal models. Here, we review advancements in each of these areas that show promise for increasing the immunogenicity of DNA vaccines.
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Affiliation(s)
- John J Suschak
- a U.S. Army Medical Research Institute of Infectious Diseases , Fort Detrick , MD , USA
| | | | - Connie S Schmaljohn
- a U.S. Army Medical Research Institute of Infectious Diseases , Fort Detrick , MD , USA
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Lack of a Functioning P2X7 Receptor Leads to Increased Susceptibility to Toxoplasmic Ileitis. PLoS One 2015; 10:e0129048. [PMID: 26053862 PMCID: PMC4460092 DOI: 10.1371/journal.pone.0129048] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 05/04/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Oral infection of C57BL/6J mice with the protozoan parasite Toxoplasma gondii leads to a lethal inflammatory ileitis. PRINCIPAL FINDINGS Mice lacking the purinergic receptor P2X7R are acutely susceptible to toxoplasmic ileitis, losing significantly more weight than C57BL/6J mice and exhibiting much greater intestinal inflammatory pathology in response to infection with only 10 cysts of T. gondii. This susceptibility is not dependent on the ability of P2X7R-deficient mice to control the parasite, which they accomplish just as efficiently as C57BL/6J mice. Rather, susceptibility is associated with elevated ileal concentrations of pro-inflammatory cytokines, reactive nitrogen intermediates and altered regulation of elements of NFκB activation in P2X7R-deficient mice. CONCLUSIONS Our data support the thesis that P2X7R, a well-documented activator of pro-inflammatory cytokine production, also plays an important role in the regulation of intestinal inflammation.
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Hwang S, Khan IA. CD8+ T cell immunity in an encephalitis model of Toxoplasma gondii infection. Semin Immunopathol 2015; 37:271-9. [PMID: 25944514 DOI: 10.1007/s00281-015-0483-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 03/22/2015] [Indexed: 12/19/2022]
Abstract
Toxoplasma gondii infection induces a robust CD8 T cell immunity in the infected host, which is critical for keeping chronic infection under control. IFNγ production and cytolytic activity exhibited by CD8 T cells are critical functions needed to prevent the reactivation of latent infection. Paradoxically, the susceptible mice infected with the parasite develop encephalitis irrespective of the presence of vigorous CD8 T cell immunity. Recent studies from our laboratory have demonstrated that these animals have defect in the memory CD8 T cell population, which become dysfunctional due to exhibition of inhibitory receptors like PD-1. Although the blockade of PD-1-PDL-1 pathway rescues the CD8 response, PD-1(hi) expressing cells are refractory to the treatment. In this review, we discuss the development of CD8 memory response during chronic infection, mechanism responsible for their dysfunctionality, and possible therapeutic measures that can be taken to reverse the process.
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Affiliation(s)
- SuJin Hwang
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, DC, USA
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Sanders KL, Fox BA, Bzik DJ. Attenuated Toxoplasma gondii Stimulates Immunity to Pancreatic Cancer by Manipulation of Myeloid Cell Populations. Cancer Immunol Res 2015; 3:891-901. [PMID: 25804437 DOI: 10.1158/2326-6066.cir-14-0235] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/16/2015] [Indexed: 01/08/2023]
Abstract
Suppressive myeloid cells represent a significant barrier to the generation of productive antitumor immune responses to many solid tumors. Eliminating or reprogramming suppressive myeloid cells to abrogate tumor-associated immune suppression is a promising therapeutic approach. We asked whether treatment of established aggressive disseminated pancreatic cancer with the immunotherapeutic attenuated Toxoplasma gondii vaccine strain CPS would trigger tumor-associated myeloid cells to generate therapeutic antitumor immune responses. CPS treatment significantly decreased tumor-associated macrophages and markedly increased dendritic cell infiltration of the pancreatic tumor microenvironment. Tumor-resident macrophages and dendritic cells, particularly cells actively invaded by CPS, increased expression of costimulatory molecules CD80 and CD86 and concomitantly boosted their production of IL12. CPS treatment increased CD4(+) and CD8(+) T-cell infiltration into the tumor microenvironment, activated tumor-resident T cells, and increased IFNγ production by T-cell populations. CPS treatment provided a significant therapeutic benefit in pancreatic tumor-bearing mice. This therapeutic benefit depended on IL12 and IFNγ production, MyD88 signaling, and CD8(+) T-cell populations. Although CD4(+) T cells exhibited activated effector phenotypes and produced IFNγ, CD4(+) T cells as well as natural killer cells were not required for the therapeutic benefit. In addition, CD8(+) T cells isolated from CPS-treated tumor-bearing mice produced IFNγ after re-exposure to pancreatic tumor antigen, suggesting this immunotherapeutic treatment stimulated tumor cell antigen-specific CD8(+) T-cell responses. This work highlights the potency and immunotherapeutic efficacy of CPS treatment and demonstrates the significance of targeting tumor-associated myeloid cells as a mechanism to stimulate more effective immunity to pancreatic cancer.
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Affiliation(s)
- Kiah L Sanders
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | - Barbara A Fox
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire
| | - David J Bzik
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire.
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Li J, Valentin A, Ng S, Beach RK, Alicea C, Bergamaschi C, Felber BK, Pavlakis GN. Differential effects of IL-15 on the generation, maintenance and cytotoxic potential of adaptive cellular responses induced by DNA vaccination. Vaccine 2015; 33:1188-96. [PMID: 25559187 DOI: 10.1016/j.vaccine.2014.12.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/24/2014] [Accepted: 12/18/2014] [Indexed: 11/30/2022]
Abstract
IL-15 is an important cytokine for the regulation of lymphocyte homeostasis. However, the role of IL-15 in the generation, maintenance and cytotoxic potential of antigen specific T cells is not fully understood. Because the route of antigenic delivery and the vaccine modality could influence the IL-15 requirement for mounting and preserving cytotoxic T cell responses, we have investigated the immunogenicity of DNA-based vaccines in IL-15 KO mice. DNA vaccination with SIV Gag induced antigen-specific CD4(+) and CD8(+) T cells in the absence of IL-15. However, the absolute number of antigen-specific CD8(+) T cells was decreased in IL-15 KO mice compared to WT animals, suggesting that IL-15 is important for the generation of maximal number of antigen-specific CD8(+) T cells. Interestingly, antigen-specific memory CD8 cells could be efficiently boosted 8 months after the final vaccination in both WT and KO strains of mice, suggesting that the maintenance of antigen-specific long-term memory T cells induced by DNA vaccination is comparable in the absence and presence of IL-15. Importantly, boosting by DNA 8-months after vaccination revealed severely reduced granzyme B content in CD8(+) T cells of IL-15 KO mice compared to WT mice. This suggests that the cytotoxic potential of the long-term memory CD8(+) T cells is impaired. These results suggest that IL-15 is not essential for the generation and maintenance of adaptive cellular responses upon DNA vaccination, but it is critical for the preservation of maximal numbers and for the activity of cytotoxic CD8(+) T cells.
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Affiliation(s)
- Jinyao Li
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States
| | - Antonio Valentin
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States.
| | - Sinnie Ng
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States
| | - Rachel Kelly Beach
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States; Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States
| | - Candido Alicea
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States
| | - Cristina Bergamaschi
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States
| | - Barbara K Felber
- Human Retrovirus Pathogenesis Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States
| | - George N Pavlakis
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, United States.
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Rodrigues L, Bonorino C. Role of IL-15 and IL-21 in viral immunity: applications for vaccines and therapies. Expert Rev Vaccines 2014; 8:167-77. [DOI: 10.1586/14760584.8.2.167] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Olias P, Meyer A, Klopfleisch R, Lierz M, Kaspers B, Gruber AD. Modulation of the host Th1 immune response in pigeon protozoal encephalitis caused by Sarcocystis calchasi. Vet Res 2013; 44:10. [PMID: 23398807 PMCID: PMC3598538 DOI: 10.1186/1297-9716-44-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 01/15/2013] [Indexed: 02/06/2023] Open
Abstract
Pigeon protozoal encephalitis (PPE) is an emerging central-nervous disease of domestic pigeons (Columba livia f. domestica) reported in Germany and the United States. It is caused by the apicomplexan parasite Sarcocystis calchasi which is transmitted by Accipter hawks. In contrast to other members of the Apicomplexa such as Toxoplasma and Plasmodium, the knowledge about the pathophysiology and host manipulation of Sarcocystis is scarce and almost nothing is known about PPE. Here we show by mRNA expression profiling a significant down-modulation of the interleukin (IL)-12/IL-18/interferon (IFN)-γ axis in the brains of experimentally infected pigeons during the schizogonic phase of disease. Concomitantly, no cellular immune response was observed in histopathology while immunohistochemistry and nested PCR detected S. calchasi. In contrast, in the late central-nervous phase, IFN-γ and tumor necrosis factor (TNF) α-related cytokines were significantly up-modulated, which correlated with a prominent MHC-II protein expression in areas of mononuclear cell infiltration and necrosis. The mononuclear cell fraction was mainly composed of T-lymphocytes, fewer macrophages and B-lymphocytes. Surprisingly, the severity and composition of the immune cell response appears unrelated to the infectious dose, although the severity and onset of the central nervous signs clearly was dose-dependent. We identified no or only very few tissue cysts by immunohistochemistry in pigeons with severe encephalitis of which one pigeon repeatedly remained negative by PCR despite severe lesions. Taken together, these observations may suggest an immune evasion strategy of S. calchasi during the early phase and a delayed-type hypersensitivity reaction as cause of the extensive cerebral lesions during the late neurological phase of disease.
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Affiliation(s)
- Philipp Olias
- Institute of Veterinary Pathology, Freie Universität Berlin, Robert-von-Ostertag-Str, 15, Berlin 14163, Germany.
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Bhadra R, Khan IA. IL-7 and IL-15 do not synergize during CD8 T cell recall response against an obligate intracellular parasite. Microbes Infect 2012; 14:1160-8. [PMID: 22885140 DOI: 10.1016/j.micinf.2012.07.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 07/19/2012] [Accepted: 07/20/2012] [Indexed: 10/28/2022]
Abstract
Long-term protection against Toxoplasma gondii is dependent on robust CD8(+) T cell immunity. In the absence of this response, the host is unable to maintain chronicity, which results in recrudescence of infection and possible death. Factors needed for the persistence of protective CD8(+) T cells against the parasite need to be evaluated. Previous studies from our laboratory have reported that synergism between γ chain cytokines like IL-7 and IL-15 is critical for the generation of CD8(+) T cell response needed for protection during acute infection. In this study we report that the situation is different during the recall response where CD8(+) T cell response is almost entirely dependent on IL-15, with IL-7 at best playing a minor role. In the absence of IL-15, CD8(+) T cells fail to respond optimally to parasitic re-challenge and hosts are unable to control their replication, which leads to their death. Thus T. gondii infection may represent a unique situation where CD8(+) T cell response during secondary challenge is primarily dependent on IL-15 with other γ chain cytokines having nominal effect. These findings provide important information regarding factors involved in the generation of protective immunity against T. gondii with strong implications in developing immunotherapeutic agents against the pathogen.
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Affiliation(s)
- Rajarshi Bhadra
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, DC 20037, USA
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Schulthess J, Meresse B, Ramiro-Puig E, Montcuquet N, Darche S, Bègue B, Ruemmele F, Combadière C, Di Santo JP, Buzoni-Gatel D, Cerf-Bensussan N. Interleukin-15-dependent NKp46+ innate lymphoid cells control intestinal inflammation by recruiting inflammatory monocytes. Immunity 2012; 37:108-21. [PMID: 22705105 DOI: 10.1016/j.immuni.2012.05.013] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 03/22/2012] [Accepted: 05/03/2012] [Indexed: 12/26/2022]
Abstract
With the goal in mind to define how interleukin-15 (IL-15) contributes to acute intestinal inflammation, we have used a mouse model of ileitis induced by oral infection with Toxoplasma gondii. We observed that a crosstalk between IL-15 and interleukin-18 (IL-18) promoted intestinal recruitment of inflammatory monocytes, where these cells participated in parasite control but also in tissue damage. A stromal source of IL-15 controlled the development of lamina propria NKp46(+)NK1.1(+) cells, whereas IL-18 produced during T. gondii infection stimulated their production of the chemokine CCL3. In turn, CCL3 attracted inflammatory monocytes via their chemokine receptor CCR1, which was indispensable for their recruitment into the inflamed gut. Collectively, these results identify the IL-15-dependent subset of intestinal NKp46(+) cells as an important source of CCL3, which can amplify intestinal inflammation via the recruitment of CCR1(+) inflammatory monocytes. Preliminary evidence suggests that this pathway might operate in Crohn's disease.
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Affiliation(s)
- Julie Schulthess
- INSERM, U989, 75015 Paris, France; Université Paris Descartes, Paris Sorbonne Cité, Institut Imagine, France
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Robert-Gangneux F, Dardé ML. Epidemiology of and diagnostic strategies for toxoplasmosis. Clin Microbiol Rev 2012; 25:264-96. [PMID: 22491772 PMCID: PMC3346298 DOI: 10.1128/cmr.05013-11] [Citation(s) in RCA: 987] [Impact Index Per Article: 82.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The apicomplexan parasite Toxoplasma gondii was discovered a little over 100 years ago, but knowledge of its biological life cycle and its medical importance has grown in the last 40 years. This obligate intracellular parasite was identified early as a pathogen responsible for congenital infection, but its clinical expression and the importance of reactivations of infections in immunocompromised patients were recognized later, in the era of organ transplantation and HIV infection. Recent knowledge of host cell-parasite interactions and of parasite virulence has brought new insights into the comprehension of the pathophysiology of infection. In this review, we focus on epidemiological and diagnostic aspects, putting them in perspective with current knowledge of parasite genotypes. In particular, we provide critical information on diagnostic methods according to the patient's background and discuss the implementation of screening tools for congenital toxoplasmosis according to health policies.
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Affiliation(s)
- Florence Robert-Gangneux
- Service de Parasitologie, Faculté de Médecine et Centre Hospitalier Universitaire de Rennes, Rennes, France.
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Perera PY, Lichy JH, Waldmann TA, Perera LP. The role of interleukin-15 in inflammation and immune responses to infection: implications for its therapeutic use. Microbes Infect 2012; 14:247-61. [PMID: 22064066 PMCID: PMC3270128 DOI: 10.1016/j.micinf.2011.10.006] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 10/18/2011] [Indexed: 01/02/2023]
Abstract
Interleukin-15 (IL-15) is a pleiotropic cytokine with a broad range of biological functions in many diverse cell types. It plays a major role in the development of inflammatory and protective immune responses to microbial invaders and parasites by modulating immune cells of both the innate and adaptive immune systems. This review provides an overview of the mechanisms by which IL-15 modulates the host response to infectious agents and its utility as a cytokine adjuvant in vaccines against infectious pathogens.
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Affiliation(s)
- Pin-Yu Perera
- Veterans Affairs Medical Center, Washington D.C. 20422
| | - Jack H. Lichy
- Veterans Affairs Medical Center, Washington D.C. 20422
| | - Thomas A. Waldmann
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Liyanage P. Perera
- Metabolism Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
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Bhadra R, Gigley JP, Khan IA. The CD8 T-cell road to immunotherapy of toxoplasmosis. Immunotherapy 2012; 3:789-801. [PMID: 21668315 DOI: 10.2217/imt.11.68] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Toxoplasma gondii infection induces a robust CD8 T-cell immunity that is critical for keeping chronic infection under control. In studies using animal models, it has been demonstrated that the absence of this response can compromise the host ability to keep chronic infection under check. Therapeutic agents that facilitate the induction and maintenance of CD8 T-cell response against the pathogen need to be developed. In the last decade, major strides in understanding the development of effector and memory response, particularly in viral and tumor models, have been made. However, factors involved in the generation of effector or memory response against T. gondii infection have not been extensively investigated. This information will be invaluable in designing immunotherapeutic regimens needed for combating this intracellular pathogen that poses a severe risk for pregnant women and immunocompromised individuals.
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Affiliation(s)
- Rajarshi Bhadra
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University, Washington, DC 20037, USA
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Chow KPN, Lee JM, Qiu JT, Liao SK, Lin SC, Hsu SL, Wu NN, Lin YF, Wu TS. Enhanced IL-10 production by CD4+ T cells primed in IL-15Rα-deficient mice. Eur J Immunol 2011; 41:3146-56. [PMID: 21874651 DOI: 10.1002/eji.201141746] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 07/11/2011] [Accepted: 08/10/2011] [Indexed: 12/12/2022]
Abstract
In this study, we investigated the functional outcomes of CD4(+) T cells primed in the absence of IL-15 transpresentation. Compared with their WT counterparts primed in WT mice, IL-15Rα KO CD4(+) T cells primed in KO mice were found to exclusively overproduce IL-10 upon in vitro restimulation(.) The comparable expression of IL-4 and Foxp3 in CD4(+) T cells primed in the WT and IL-15Rα KO mice indicated that this was neither due to T(H) 2- nor Treg cell-differentiation. IL-10 overproduction was also observed when OVA-specific TCR transgenic CD4(+) T (OT-II) cells were primed in KO mice, excluding an intrinsic deficiency of KO CD4(+) T cells. To investigate the WT and KO microenvironment, DCs from both WT and IL-15Rα KO mice were compared. DCs from both backgrounds were indistinguishable in their steady-state survival and in their expression of MHC class II and costimulatory molecules CD80, CD86, and CD40. However, IL-15Rα KO DCs primed OT-II cells in vitro to produce higher levels of IL-10 upon their restimulation. Additionally, IL-15Rα KO DCs produced significantly more IL-10 upon activation, and IL-10 neutralization during DC-mediated in vitro priming abolished IL-10 overproduction by CD4(+) T cells. Thus, IL-15Rα KO DCs provide an IL-10-enriched environment that preferentially primes CD4(+) T cells for more IL-10 production, highlighting a regulatory role for IL-15 transpresentation in CD4(+) T-cell priming.
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Affiliation(s)
- Kai-Ping N Chow
- Department of Microbiology and Immunology, Chang Gung University,Taoyuan, Taiwan, ROC
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20
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CD8 T Cells and Toxoplasma gondii: A New Paradigm. J Parasitol Res 2011; 2011:243796. [PMID: 21687650 PMCID: PMC3112509 DOI: 10.1155/2011/243796] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 03/10/2011] [Indexed: 01/09/2023] Open
Abstract
CD8 T cells are essential for control of Toxoplasma gondii infection. Once activated they undergo differentiation into short-lived effector and memory precursor effector cells. As effector cells, CD8 T cells exert immune pressure on the parasite via production of inflammatory cytokines and through their cytolytic activity. Once immune control has been established, the parasite encysts and develops into chronic infection regulated by the memory CD8 T-cell population. Several signals are needed for this process to be initiated and for development of fully differentiated memory CD8 T cells. With newly developed tools including CD8 T-cell tetramers and TCR transgenic mice, dissecting the biology behind T. gondii-specific CD8 T-cell responses can now be more effectively addressed. In this paper, we discuss what is known about the signals required for effective T. gondii-specific CD8 T-cell development, their differentiation, and effector function.
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Pydi SS, Bandaru AR, Venkatasubramanian S, Jonnalagada S, Valluri VL. Vaccine for tuberculosis: Up-regulation of IL-15 by Ag85A and not by ESAT-6. Tuberculosis (Edinb) 2011; 91:136-9. [DOI: 10.1016/j.tube.2010.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Revised: 11/23/2010] [Accepted: 12/15/2010] [Indexed: 10/18/2022]
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Di Sabatino A, Calarota SA, Vidali F, MacDonald TT, Corazza GR. Role of IL-15 in immune-mediated and infectious diseases. Cytokine Growth Factor Rev 2011; 22:19-33. [DOI: 10.1016/j.cytogfr.2010.09.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 09/09/2010] [Accepted: 09/21/2010] [Indexed: 12/31/2022]
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Bhadra R, Guan H, Khan IA. Absence of both IL-7 and IL-15 severely impairs the development of CD8 T cell response against Toxoplasma gondii. PLoS One 2010; 5:e10842. [PMID: 20520779 PMCID: PMC2877110 DOI: 10.1371/journal.pone.0010842] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 05/02/2010] [Indexed: 11/21/2022] Open
Abstract
CD8+ T cells play an essential role in the protection against both acute as well as chronic Toxoplasma gondii infection. Although the role of IL-15 has been reported to be important for the development of long-term CD8+ T cell immunity against the pathogen, the simultaneous roles played by both IL-15 and related γ-chain family cytokine IL-7 in the generation of this response during acute phase of infection has not been described. We demonstrate that while lack of IL-7 or IL-15 alone has minimal impact on splenic CD8+ T cell maturation or effector function development during acute Toxoplasmosis, absence of both IL-7 and IL-15 only in the context of infection severely down-regulates the development of a potent CD8+ T cell response. This impairment is characterized by reduction in CD44 expression, IFN-γ production, proliferation and cytotoxicity. However, attenuated maturation and decreased effector functions in these mice are essentially downstream consequences of reduced number of antigen-specific CD8+ T cells. Interestingly, the absence of both cytokines did not impair initial CD8+ T cell generation but affected their survival and differentiation into memory phenotype IL-7Rαhi cells. Significantly lack of both cytokines severely affected expression of Bcl-2, an anti-apoptotic protein, but minimally affected proliferation. The overarching role played by these cytokines in eliciting a potent CD8+ T cell immunity against T. gondii infection is further evidenced by poor survival and high parasite burden in anti IL-7 treated IL-15−/− mice. These studies demonstrate that the two cytokines, IL-7 and IL-15, are exclusively important for the development of protective CD8+ T cell immune response against T. gondii. To the best of our knowledge this synergism between IL-7 and IL-15 in generating an optimal CD8+ T cell immunity against intracellular parasite or any other infectious disease model has not been previously reported.
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Affiliation(s)
- Rajarshi Bhadra
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, D. C., United States of America
| | - Hongbing Guan
- Department of Pathology, Microbiology and Immunology, University of South Carolina School of Medicine, Columbia, South Carolina, United States of America
| | - Imtiaz A. Khan
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, D. C., United States of America
- * E-mail:
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Bigalke B, Schwimmbeck PL, Haas CS, Lindemann S. Effect of interleukin-15 on the course of myocarditis in Coxsackievirus B3-infected BALB/c mice. Can J Cardiol 2009; 25:e248-54. [PMID: 19584981 DOI: 10.1016/s0828-282x(09)70511-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE Cytokines have an important role in both the initiation and perpetuation of viral myocarditis. Because a causative therapy of myocarditis is not yet well established and immunomodulation is a promising approach, the influence of interleukin (IL)-15, a proinflammatory cytokine, on the course of experimental myocarditis in Coxsackievirus B3 (CVB3)-infected mice was examined. METHODS Hearts from CVB3-infected (n=14), sham-infected (n=14) and CVB3-infected BALB/c mice treated with IL-15 (n=6) or a competitive IL-15 fusion protein (n=6) were analyzed for hemodynamic function, cellular infiltrates and myocardial collagen content. RESULTS Induction of myocarditis was associated with significant loss of body and heart weight, decreased left ventricular function, and increased collagen content and cellular infiltrates in the myocardium. Treatment of infected animals with IL-15 resulted in normalization of body and heart weight, and significantly improved systolic and diastolic left ventricular function, comparable with that of uninfected animals. This was paralleled by a significant reduction of myocardial collagen content to levels observed in animals without disease and by markedly reduced cellular infiltration of lymphocytes and macrophages in the myocardium. Inhibition of intrinsic IL-15 with IL-15 fusion protein tended to aggravate the disease. CONCLUSIONS Treatment with IL-15 has a positive effect on CVB3- induced murine myocarditis and seems to be a promising approach to modifying clinical course, hemodynamics and histopathology of virus-induced myocarditis. Further studies are needed to identify the underlying mechanisms.
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Affiliation(s)
- Boris Bigalke
- Medizinische Klinik III, Klinik für Kardiologie und Kreislauferkrankungen, Eberhard Kearls Universität Tübingen, D-72076 Tübingen, Germany
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25
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Rochman Y, Spolski R, Leonard WJ. New insights into the regulation of T cells by gamma(c) family cytokines. Nat Rev Immunol 2009; 9:480-90. [PMID: 19543225 DOI: 10.1038/nri2580] [Citation(s) in RCA: 783] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Common cytokine receptor gamma-chain (gamma(c)) family cytokines have crucial roles in the development, proliferation, survival and differentiation of multiple cell lineages of both the innate and adaptive immune systems. In this Review, we focus on our current understanding of the distinct and overlapping effects of interleukin-2 (IL-2), IL-7, IL-9, IL-15 and IL-21, as well as the IL-7-related cytokine thymic stromal lymphopoietin (TSLP), on the survival and proliferation of conventional alphabeta T cells, gammadelta T cells and regulatory T cells. This knowledge potentially allows for the therapeutic manipulation of immune responses for the treatment of cancer, autoimmunity, allergic diseases and immunodeficiency, as well as for vaccine development.
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Affiliation(s)
- Yrina Rochman
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1674, USA
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26
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Moretto MM, Lawlor EM, Khan IA. Aging mice exhibit a functional defect in mucosal dendritic cell response against an intracellular pathogen. THE JOURNAL OF IMMUNOLOGY 2008; 181:7977-84. [PMID: 19017989 DOI: 10.4049/jimmunol.181.11.7977] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Down-regulation of the immune response in aging individuals puts this population at a potential risk against infectious agents. In-depth studies conducted in humans and mouse models have demonstrated that with increasing age, the T cell immune response against pathogens is compromised and response to vaccinations is subdued. In the present study, using a mouse model, we demonstrate that older animals exhibit greater susceptibility to Encephalitozoon cuniculi infection, and their ability to evoke an Ag-specific T cell response at the gut mucosal site is reduced. The dampening of T cell immunity was due to the defective priming by the dendritic cells (DC) isolated from the mucosal tissues of aging animals. When primed with DC from younger mice, T cells from older animals were able to exhibit an optimal Ag-specific response. The functional defect in DC from older mice can be attributed to a large extent to reduced IL-15 message in these cells, which can be reversed by addition of exogenous IL-15 to the cultures. IL-15 treatment led to optimal expression of costimulatory molecules (CD80 and CD86) on the surface of older DC and restored their ability to prime a T cell response against the pathogen. To our knowledge, this is the first report which demonstrates the inability of the DC population from aging animals to prime a robust T cell response against an infectious agent. Moreover, the observation that IL-15 treatment can reverse this defect has far-reaching implications in developing strategies to increase vaccination protocols for aging populations.
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Affiliation(s)
- Magali M Moretto
- Department of Microbiology, Immunology and Tropical Medecine, George Washington University, Washington, DC 20037, USA
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27
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Miller CM, Boulter NR, Ikin RJ, Smith NC. The immunobiology of the innate response to Toxoplasma gondii. Int J Parasitol 2008; 39:23-39. [PMID: 18775432 DOI: 10.1016/j.ijpara.2008.08.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 08/07/2008] [Accepted: 08/11/2008] [Indexed: 01/17/2023]
Abstract
Toxoplasma gondii is a unique intracellular parasite. It can infect a variety of cells in virtually all warm-blooded animals. It has a worldwide distribution and, overall, around one-third of people are seropositive for the parasite, with essentially the entire human population being at risk of infection. For most people, T. gondii causes asymptomatic infection but the parasite can cause serious disease in the immunocompromised and, if contracted for the first time during pregnancy, can cause spontaneous abortion or congenital defects, which have a substantial emotional, social and economic impact. Toxoplasma gondii provokes one of the most potent innate, pro-inflammatory responses of all infectious disease agents. It is also a supreme manipulator of the immune response so that innate immunity to T. gondii is a delicate balance between the parasite and its host involving a coordinated series of cellular interactions involving enterocytes, neutrophils, dendritic cells, macrophages and natural killer cells. Underpinning these interactions is the regulation of complex molecular reactions involving Toll-like receptors, activation of signalling pathways, cytokine production and activation of anti-microbial effector mechanisms including generation of reactive nitrogen and oxygen intermediates.
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Affiliation(s)
- Catherine M Miller
- Institute for the Biotechnology of Infectious Diseases, University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia
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Abstract
PURPOSE OF REVIEW To examine the type and risk of infections in humans and mice deficient in proinflammatory cytokines. Naturally occurring or manipulated genetic defects of tumor necrosis factor, interleukins-1, -6, -12, and -15, and interferon-gamma are examined for their increased susceptibility to, or protection from, infection. RECENT FINDINGS Interleukin-12p40 and interferon-gamma-blockers may lead to increased incidence of infections with intracellular bacteria, parasites, and fungi. In addition, we may see viral infections with interferon-gamma-blockers. Increased risk of infections is unlikely with either interleukin-1- or interleukin-15-blockers. Interleukin-6-blockers may lead to increased risk of infection with extracellular bacteria, viruses, parasites and fungi. SUMMARY In tumor necrosis factor knockout mice, increased susceptibility to pathogens are reported that are normally controlled by granuloma formation. In patients treated with tumor necrosis factor-blockers, a two-fold increase of granulomatous infections, predominantly reactivation of latent tuberculosis, is found. The infections detected in tumor necrosis factor knockout mice were accurate for predicting the infections observed when using tumor necrosis factor-blockers. If a similar correlation exists for other cytokines, the use of interferon-gamma and interleukin-12p40 blockers, and possibly interleukin-6 blockers, will lead to an increased risk for severe infections. Care should be taken when new cytokine blockers/antagonists are introduced.
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Coinfection with Heligmosomoides polygyrus fails to establish CD8+ T-cell immunity against Toxoplasma gondii. Infect Immun 2008; 76:1305-13. [PMID: 18195022 DOI: 10.1128/iai.01236-07] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD8+ T-cell immunity is important for long-term protection against Toxoplasma gondii infection. However, a Th1 cytokine environment, especially the presence of gamma interferon (IFN-), is essential for the development of primary CD8+ T-cell immunity against this obligate intracellular pathogen. Earlier studies from our laboratory have demonstrated that mice lacking optimal IFN- levels fail to develop robust CD8+ T-cell immunity against T. gondii. In the present study, induction of primary CD8+ T-cell immune response against T. gondii infection was evaluated in mice infected earlier with Heligmosomoides polygyrus, a gastrointestinal worm known to evoke a polarized Th2 response in the host. In the early stage of T. gondii infection, both CD4 and CD8+ T-cell responses against the parasite were suppressed in the dually infected mice. At the later stages, however, T. gondii-specific CD4+ T-cell immunity recovered, while CD8+ T-cell responses remained low. Unlike in mice infected with T. gondii alone, depletion of CD4+ T cells in the dually infected mice led to reactivation of chronic infection, leading to Toxoplasma-related encephalitis. Our observations strongly suggest that prior infection with a Th2 cytokine-polarizing pathogen can inhibit the development of CD8+ T-cell immune response against T. gondii, thus compromising long-term protection against a protozoan parasite. This is the first study to examine the generation of CD8+ T-cell immune response in a parasitic nematode and protozoan coinfection model that has important implications for infections where a CD8+ T-cell response is critical for host protection and reduced infection pathology.
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Bibliography. Current world literature. Myositis and myopathies. Curr Opin Rheumatol 2007; 19:651-3. [PMID: 17917548 DOI: 10.1097/bor.0b013e3282f20347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Purton JF, Tan JT, Rubinstein MP, Kim DM, Sprent J, Surh CD. Antiviral CD4+ memory T cells are IL-15 dependent. ACTA ACUST UNITED AC 2007; 204:951-61. [PMID: 17420265 PMCID: PMC2118539 DOI: 10.1084/jem.20061805] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Survival and intermittent proliferation of memory CD4(+) and CD8(+) T cells appear to be controlled by different homeostatic mechanisms. In particular, contact with interleukin (IL)-15 has a decisive influence on memory CD8(+) cells, but not memory CD4(+) cells. Past studies of memory CD4(+) cells have relied heavily on the use of naturally occurring memory phenotype (MP) cells as a surrogate for antigen (Ag)-specific memory cells. However, we show here that MP CD4(+) cells contain a prominent subset of rapidly proliferating major histocompatibility complex (MHC) II-dependent cells. In contrast, Ag-specific memory CD4 cells have a slow turnover rate and are MHC II independent. In irradiated hosts, these latter cells ignore IL-15 and expand in response to the elevated levels of IL-7 in the lymphopenic hosts. In contrast, in normal nonlymphopenic hosts where IL-7 levels are low, memory CD4 cells are heavily dependent on IL-15. Significantly, memory CD4(+) responsiveness to endogenous IL-15 reflects marked competition from other cells, especially CD8(+) and natural killer cells, and increases considerably after removal of these cells. Therefore, under normal physiological conditions, homeostasis of CD8(+) and CD4(+) memory cells is quite similar and involves IL-15 and IL-7.
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Affiliation(s)
- Jared F Purton
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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Khan IA. Toll road for Toxoplasma gondii: the mystery continues. Trends Parasitol 2007; 23:1-3. [PMID: 17084106 DOI: 10.1016/j.pt.2006.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Revised: 09/18/2006] [Accepted: 10/20/2006] [Indexed: 11/26/2022]
Abstract
Toll-like receptors (TLRs) are considered to be essential for the initiation of immune responses against pathogens. Although myeloid differentiation factor 88 an adaptor molecule for most TLRs, is important for protection against Toxoplasma gondii, the TLR responsible for eliciting an immune response against this obligate intracellular pathogen remains unknown. A recent article reports that mice lacking TLR9 cannot develop severe inflammatory responses to T. gondii infection. The implications of this finding are discussed here.
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Affiliation(s)
- Imtiaz A Khan
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University Medical Center, Ross Hall Suite 736, 2300 Eye Street NW, Washington, DC 20037, USA.
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