scholarly journals Helminths' antigens differentially modulate the activation of SARS-CoV-2-reactive helper and cytotoxic T cells in COVID-19 patients and healthy blood donors.

2022 ◽  
Author(s):  
Tomabu Adjobimey ◽  
Julia Meyer ◽  
Vedrana Terkeš ◽  
Marijo Parcina ◽  
Achim Hoerauf
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
Sub Saharan Africa ◽  
Cytotoxic T Cell ◽  
Immune Reactivity ◽  
Sub Saharan ◽  
Cytotoxic T Cell Responses ◽  
The Impact

Abstract Background Contrary to the predictions, prevalence and mortality due to COVID-19 have remained moderate on the African continent. Several factors, including age, genetics, vaccines, and co-infections, might impact the course of the pandemic in Africa. Helminths are highly endemic in Sub-Saharan Africa and are renowned for their ability to modulate their host immune reactions. Methods Here we analyzed in vitro the impact of major helminth antigens on the immune reactivity to SARS-CoV-2 in COVID-19 patients using flow cytometry and Luminex. Results: We observed that helminth antigens significantly reduced the frequency of SARS-CoV-2-reactive CD4+ T helper cells. In contrast, the expression of SARS-CoV-2-reactive CD8+ T cells was not affected. In addition, stimulation with helminth antigens was associated with increased IL-10 and a reduction of IFNγ and TNFα. Conclusion: Our data offer a plausible explanation for the moderate incidence of COVID-19 in Africa and support the hypothesis that helper T cell-mediated immune responses to SARS-CoV-2 are mitigated in the presence of helminth antigens, while virus-specific cytotoxic T cell responses are maintained.

Helminths' antigens differentially modulate the activation of SARS-CoV-2-reactive helper and cytotoxic T cells in COVID-19 patients and healthy blood donors

2021 ◽  
Author(s):  
Tomabu Adjobimey ◽  
Julia Meyer ◽  
Vedrana Terkeš ◽  
Marijo Parcina ◽  
Achim Hoerauf
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
Sub Saharan Africa ◽  
Cytotoxic T Cell ◽  
Immune Reactivity ◽  
Sub Saharan ◽  
Cytotoxic T Cell Responses ◽  
The Impact

Abstract Background Contrary to the predictions, prevalence and mortality due to COVID-19 have remained moderate on the African continent. Several factors, including age, genetics, vaccines, and co-infections, might impact the course of the pandemic in Africa. Helminths are highly endemic in Sub-Saharan Africa and are renowned for their ability to modulate their host immune reactions. Methods Here we analyzed in vitro the impact of major helminth antigens on the immune reactivity to SARS-CoV-2 in COVID-19 patients using flow cytometry and Luminex. Results: We observed that helminth antigens significantly reduced the frequency of SARS-CoV-2-reactive CD4+ T helper cells. In contrast, the expression of SARS-CoV-2-reactive CD8+ T cells was not affected. In addition, stimulation with helminth antigens was associated with increased IL-10 and a reduction of IFNγ and TNFα. Conclusion: Our data offer a plausible explanation for the moderate incidence of COVID-19 in Africa and support the hypothesis that helper T cell-mediated immune responses to SARS-CoV-2 are mitigated in the presence of helminth antigens, while virus-specific cytotoxic T cell responses are maintained.

scholarly journals Role of viral infectivity in the induction of influenza virus-specific cytotoxic T cells.

1978 ◽  
Vol 147 (4) ◽  
pp. 1236-1252 ◽  
Author(s):  
T J Braciale ◽  
K L Yap
Keyword(s):  
T Cells ◽  
Influenza Virus ◽  
T Cell ◽  
Cell Response ◽  
Infectious Virus ◽  
Cytotoxic T Cells ◽  
T Cell Response ◽  
Cytotoxic T Cell

This report examines the requirement for infectious virus in the induction of influenza virus-specific cytotoxic T cells. Infectious influenza virus was found to be highly efficient at generating both primary and secondary cytotoxic T-cell response in vivo. Inactivated influenza virus however, failed to stimulate a detectable cytotoxic T-cell response in vivo even at immunizing doses 10(5)-10(6)-fold higher than the minimum stimulatory dose of infectious virus. Likewise inactivated virus failed to sensitize target cells for T cell-mediated lysis in vitro but could stimulate a specific cytotoxic response from primed cells in vitro. Possible requirements for the induction of virus-specific cytotoxic T-cell responses are discussed in light of these observations and those of other investigators.

scholarly journals Specificity of cytotoxicity T cells directed to influenza virus hemagglutinin.

1979 ◽  
Vol 149 (4) ◽  
pp. 856-869 ◽  
Author(s):  
T J Braciale
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
Type A ◽  
Cross Reactivity ◽  
Cytotoxic T Cell ◽  
Target Cells ◽  
Effector Cells ◽  
Cell Induction

Purified type A influenza viral hemagglutinin stimulates an in vitro cell-mediated cytotoxic cell response that exhibits a high degree of specificity for the immunizing hemagglutinin. The response magnitude is proportional to the hemagglutinin dose used for stimulation. The lytic activity of the effector cells is H-2 restricted. Analysis of the specificity of the response indicated that these cytotoxic T cells readily distinguish target cells expressing serologically unrelated hemagglutinin from target cells bearing hemagglutinins serologically related to the stimulating hemagglutinin. Further analysis of the fine specificity of cytotoxic T-cell recognition with serologically cross-reactive type A influenza hemagglutinins revealed a hierarchy of cross-reactivity among these hemagglutinins that was the converse of the serologic hierarchy. These results are discussed in terms of possible differences and similarities in the specificity repertoire of cytotoxic T cells and antibodies. Possible implications of these findings from the standpoint of cytotoxic T-cell induction are also discussed.

scholarly journals In vitro generation of antigen-specific helper T cells that collaborate with cytotoxic T-cell precursors.

1978 ◽  
Vol 148 (6) ◽  
pp. 1579-1591 ◽  
Author(s):  
L L Baum ◽  
L M Pilarski
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic T Cells ◽  
Cell Activity ◽  
Helper T Cells ◽  
Helper Cell ◽  
Cytotoxic T Cell ◽  
Spleen Cells

Antigen-specific helper T cells are required in the generation of cytotoxic T cells from thymocyte precursors. We have demonstrated that these alloantigen-specific helper cells can be generated in vitro and that both the quantity and quality of the helpers appear to be superior to the help obtained from unprimed spleen cells. Optimal helper cell activity is produced at day two of culture when CBA splenic helper precursors are stimulated by irradiated allogeneic spleen cells. Helper cell precursors are antigen-specific cells which cannot be instructed to express forbidden receptor specificities and bear theta antigen on their surface. The helper effectors are radioresistant, theta-bearing, and antigen-specific cells.

scholarly journals Th17 Cell Enhances CD8 T-Cell Cytotoxicity via IL-21 Production in Emphysema Mice

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Min-Chao Duan ◽  
Ying Huang ◽  
Xiao-Ning Zhong ◽  
Hai-Juan Tang
Keyword(s):  
T Cells ◽  
T Cell ◽  
Inflammatory Response ◽  
Peripheral Blood ◽  
Th17 Cells ◽  
Cell Function ◽  
Cytotoxic T Cell ◽  
Protein Levels ◽  
The Impact

Emphysema is a T-cell mediated autoimmune disease caused predominantly by cigarette smoking. Th17 cells and related cytokines may contribute to this disorder. However, the possible implication of Th17 cells in regulating inflammatory response in emphysema remains to be elucidated. In the current study, we tested the protein levels of IL-17 and IL-21 in peripheral blood and lung tissues from cigarette-smoke- (CS-) exposed mice and air-exposed mice, analyzed the frequencies of CD4+IL-17+(Th17) cells, IL-21+Th17 cells, and CD8+IL-21R+T cells in peripheral blood and lung tissues of mice, and their relationship with emphysematous lesions, and explored the impact of IL-21 on cytotoxic CD8+T cells functionin vitro.It was found that the frequencies of Th17, IL-21+Th17, and CD8+IL-21R+T cells and the levels of IL-17 and IL-21 of CS-exposed mice were much higher than those of the air-exposed mice and correlated with emphysematous lesions. Additionally, the number of IL-21+Th17 cells positively correlated with the number of CD8+IL-21R+T cells. Thein vitroexperiments showed that IL-21 significantly augmented the secretion of perforin and granzyme B in CD8+T cells from CS-exposed mice. These data indirectly provide evidence that Th17 cells could be involved in the control of the local and system inflammatory response in emphysema by regulating CD8+cytotoxic T-cell function.

scholarly journals Virus-Specific CD4+ and CD8+ Cytotoxic T-Cell Responses and Long-Term T-Cell Memory in Individuals Vaccinated against Polio

2005 ◽  
Vol 79 (10) ◽  
pp. 5988-5995 ◽  
Author(s):  
Rahnuma Wahid ◽  
Martin J. Cannon ◽  
Marie Chow
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Responses ◽  
Neutralizing Antibody ◽  
T Cell Response ◽  
Cytotoxic T Cell ◽  
Cell Responses ◽  
Cytotoxic T Cell Responses

ABSTRACT The presence of poliovirus (PV)-specific CD4+ T cells in individuals vaccinated against polio has been shown, but CD8+ T-cell responses have not been described. Here, we functionally characterize the CD4+ T-cell response and show for the first time that dendritic cells and macrophages can stimulate PV-specific CD8+ T-cell responses in vitro from vaccinees. Both CD4+ T and CD8+ T cells secrete gamma interferon in response to PV antigens and are cytotoxic via the perforin/granzyme B-mediated pathway. Furthermore, the T cells also recognize and kill Sabin 1 vaccine-infected targets. The macrophage-stimulated CD4+ T and CD8+ T cells most likely represent memory T cells that persist for long periods in vaccinated individuals. Thus, immunity to PV vaccination involves not only an effective neutralizing antibody titer but also long-term CD4+ and CD8+ cytotoxic T-cell responses.

scholarly journals The interaction between CD8+ cytotoxic T cells and Leishmania-infected macrophages.

1991 ◽  
Vol 174 (3) ◽  
pp. 499-505 ◽  
Author(s):  
L E Smith ◽  
M Rodrigues ◽  
D G Russell
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Clone ◽  
Cytotoxic T Cells ◽  
T Cell Response ◽  
Cytotoxic T Cell ◽  
T Cell Clone ◽  
Vitro Model ◽  
Leishmania Parasites

Leishmania is resident within the macrophages of its vertebrate host. In any intramacrophage infection, where the pathogen is present in a form capable of mediating cell to cell transmission, the contribution of a cytotoxic T cell response to protective immunity is questionable. This study presents data from an in vitro model designed to elucidate the outcome of an interaction between CD8+, cytotoxic T cells and infected macrophages. Experiments were conducted with an H-2d-restricted, cytotoxic CD8+ T cell clone and Leishmania parasites present in mixed macrophage cultures, with the parasites confined to either histocompatible BALB/c macrophages, or incompatible CBA macrophages. Initial experiments indicated that the viability of Leishmania was unaffected by the lysis of its host macrophage by cytotoxic T cells. However, extended experiments showed that the parasites were killed between 24 and 72 h. The same results were obtained regardless of whether the parasites were resident in the target, BALB/c, macrophages or the bystander, CBA, macrophages. Addition of neutralizing, anti-IFN-g antibody to the cultures ablated most of the leishmanicidal behavior, indicating that parasite death was attributable to macrophage activation, resulting from cytokine secretion from the T cells following the initial recognition event.

scholarly journals Heat Shock Treatment of Tumor Lysate-Pulsed Dendritic Cells Enhances Their Capacity to Elicit Antitumor T Cell Responses against Medullary Thyroid Carcinoma

2006 ◽  
Vol 91 (11) ◽  
pp. 4571-4577 ◽  
Author(s):  
Thomas Bachleitner-Hofmann ◽  
Michaela Strohschneider ◽  
Peter Krieger ◽  
Monika Sachet ◽  
Peter Dubsky ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Heat Shock ◽  
Tumor Cells ◽  
T Cell Responses ◽  
Cytotoxic T Cell ◽  
Tumor Lysate ◽  
Cell Responses ◽  
Cytotoxic T Cell Responses

Abstract Background: In vitro and in vivo studies have shown that dendritic cells (DCs) can stimulate antitumor T cell responses against medullary thyroid carcinoma (MTC). However, despite promising results in selected cases, the clinical efficacy of DC immunotherapy in patients with MTC has been limited. Recently, it has been demonstrated in mice that heat shock enhances the capacity of bone-marrow-derived DCs to stimulate antigen-specific T cells. The aim of our investigations was to evaluate whether heat shock also increases the capacity of human monocyte-derived DCs to stimulate antitumor T cell responses against MTC tumor cells. Methods: DCs from six patients with metastatic MTC were pulsed with tumor lysate derived from allogeneic MTC tumor cells and were heat shocked for 12 h at 40 C or kept at 37 C. Thereafter, the DCs were matured and cocultured with T cells. Finally, the cytotoxic activity of T cells against MTC tumor cells was measured in vitro. Results: In all patient samples, cytotoxic T cell responses against MTC tumor cells could be induced. Notably, heat-shocked DCs were more potent stimulators of cytotoxic T cell responses than control DCs, with T cells stimulated with heat-shocked DCs displaying a significantly increased cytotoxic activity against MTC tumor cells as compared with T cells stimulated with control DCs. In none of the experiments was a cytotoxic T cell response against unrelated pancreatic tumor cells (PANC-1) observed, using both control and heat-shocked DCs. Conclusions: Our study shows that heat-shocking DCs may be a valuable strategy to increase the immunostimulatory capacity of DCs used for immunotherapy of MTC.

scholarly journals Protective Cytotoxic T-Cell Responses Induced by Venezuelan Equine Encephalitis Virus Replicons Expressing Ebola Virus Proteins

2005 ◽  
Vol 79 (22) ◽  
pp. 14189-14196 ◽  
Author(s):  
Gene G. Olinger ◽  
Michael A. Bailey ◽  
John M. Dye ◽  
Russell Bakken ◽  
Ana Kuehne ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Ebola Virus ◽  
Cytotoxic T Cells ◽  
T Cell Responses ◽  
Cytotoxic T Cell ◽  
Equine Encephalitis Virus ◽  
Cell Responses ◽  
Cytotoxic T Cell Responses ◽  
Virus Proteins

ABSTRACT Infection with Ebola virus causes a severe disease accompanied by high mortality rates, and there are no licensed vaccines or therapies available for human use. Filovirus vaccine research efforts still need to determine the roles of humoral and cell-mediated immune responses in protection from Ebola virus infection. Previous studies indicated that exposure to Ebola virus proteins expressed from packaged Venezuelan equine encephalitis virus replicons elicited protective immunity in mice and that antibody-mediated protection could only be demonstrated after vaccination against the glycoprotein. In this study, the murine CD8+ T-cell responses to six Ebola virus proteins were examined. CD8+ T cells specific for Ebola virus glycoprotein, nucleoprotein, and viral proteins (VP24, VP30, VP35, and VP40) were identified by intracellular cytokine assays using splenocytes from vaccinated mice. The cells were expanded by restimulation with peptides and demonstrated cytolytic activity. Adoptive transfer of the CD8+ cytotoxic T cells protected filovirus naïve mice from challenge with Ebola virus. These data support a role for CD8+ cytotoxic T cells as part of a protective mechanism induced by vaccination against six Ebola virus proteins and provide additional evidence that cytotoxic T-cell responses can contribute to protection from filovirus infections.

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