HIV-specific IL-2(+) and/or IFN-γ(+) CD8(+) T cell responses during chronic HIV-1 infection in former blood donors

Abstract

Objective: Conflicting data have been generated from previous studies to determine which kind of relationship exists between HIV-1 specific CD8 Tcell responses and HIV-1 viral load or CD4 count over the course of infection. In this study, 153 HIV-1 infected LTNPs were enrolled to investigate the role of HIV-1 specific CD8 T-cell responses in chronic HIV-1 infection among HIV-1 infected former blood donors.

Methods: The patients were stratified into three groups according to CD4 count: CD4≥500 cells/μL; 350 cells/μL≤CD4<500 cells/μL; CD4<350 cells/μL. PBMCs were isolated from the patients' anticoagulated blood samples. IL-2 and IFN-γ secretions of CD 8 T cells against 17 HIV-1 consensus B full peptide pools were analyzed by using ICS assay.

Results: An overall inverse correlation were observed between CD4 count and plasma viral load. Although no significant difference was observed during the comparisons of frequency/breadth of HIV-1 specific CD8 T cell responses, CD4 count stratification analysis showed that different correlation pattern existed in three strata: as for patients whose CD4 counts were less than 350 cells/μL, no significant correlations were identified between frequency/breadth of HIV-1 specific CD8 T cell responses and CD4 count/viral load; as for patients whose CD4 counts ranged from 350 cells/μL to 500 cells/μL, significant correlation was only observed between the response breadth of IL-2+IFN-γ+ CD8 T cells and CD4 count; however, as for patients whose CD4 counts were more than 500 cells/μL, direct correlations were identified between IL-2+IFN-γ+/IL-2+/IFN-γ+ CD8 T cells and viral load or CD4 count.

Conclusions: Universal consistent inverse correlation was only indentified between CD4 count and viral load. The relationship between HIV-1 specific CD8 T cell responses and CD4 count/viral load varied in different CD4 strata, which showed that better preserved CD4 T cells were correlated with better CD8 T cell functions.