Interferon gamma (IFN-?) negative CD4+ and CD8+ T-cells can produce immune mediators in response to viral antigens.

ABSTRACT: Evaluation of antigen-specific T-cell responses to viral antigens is frequently performed on IFN-? secreting cells. However, T-cells are capable of producing many more functions than just IFN-?, some of which, like Perforin, are associated with immune protection in HIV-1 disease elite controllers. We evaluated the extent of missed T-cell functions when IFN-? secretion is used as a surrogate marker for further evaluation of T-cell functions. Intracellular cytokine staining assay and flow cytometry were used to assess peripheral blood mononuclear cells (PBMCs) from 31 HIV-infected ART-naive individuals for the extent to which gated CD4+ and CD8+ IFN-? producing and non-producing T-cells also secreted IL-2, Perforin, and TNF-? functions. Similarly, the extent of missed virus-specific responses in IFN-? ELISpot assay negative T-cells from 5 HIV-1 uninfected individuals was evaluated. Cells from HIV-infected individuals were stimulated with pooled consensus group M (Con M) peptides; and those from healthy individuals were stimulated with pooled adenovirus (Ad) peptides. Overall, frequencies of virus-specific IFN-? secreting CD4+ and CD8+ cells were low. Proportions of IFN-? negative CD4+ expressing IL-2, Perforin, or TNF-? to Con M were significantly higher (5 of 7 functional profiles) than the corresponding IFN-? positive CD4+ (0 of 7) T-cell phenotype, p?=?0.02; Fisher's Exact test. Likewise, proportions of CD8+ T-cells expressing other functions were significantly higher in 4 of the 7 IFN-? negative CD8+ T-cells. Notably, newly stimulated Perforin, identified as Perforin co-expression with IL-2 or TNF-?, was significantly higher in IFN-? negative CD8+ T-cell than in the positive CD8+ T-cells. Using SEB, lower responses in IFN-? positive cells were most associated with CD4+ than CD8+ T-cells. These findings suggest that studies evaluating immunogenicity in response to HIV and Adenovirus viral antigens should not only evaluate T-cell responsiveness among IFN-? producing cells but also among those T-cells that do not express IFN-?.

SUBMITTER: Nakiboneka R 

PROVIDER: S-EPMC6290111 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature