HIV-Specific IL-2+ and/or IFN-γ+ CD8+ T Cell Reponses during Chronic HIV-1 Infection in Former Blood Donors

Key words: 
• HIV-1 /
• subtype B' /
• CD8 T cell response /
• IFN-γ /
• IL-2 /
• ICS

Abstract: Objective Conflicting data have been generated from previous studies to determine which kind of relationship exists between HIV-1 specific CD8 T-cell 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.