cTfh-mediated memory B cell help is impaired in late stage acute HIV-infected individuals.

<p>PBMCs from week 0 stage 1/2 (n = 9) and stage 3 (n = 4–7) individuals were sorted. cTfh (CD3⁺CD4⁺CD45RA^-CXCR5⁺CXCR3^-) or the less efficient T-helper cells (CD3⁺CD4⁺CD45RA^-CXCR5⁺CXCR3⁺) denoted CXCR5⁺CXCR3⁺ were placed in culture with autologous resting memory B cells (CD19⁺CD10^-CD21⁺CD27⁺) in the presence of SEB. Quantification of cTfh-mediated B cell help was carried out by measuring (A) total and (B) HIV-specific IgG ELISA in 7 day culture supernatant. Absolute numbers of live (C) B and (D) T cells were quantified. (E) Correlation analysis was carried out between the absolute number of B cells and HIV-specific IgG. (F) HIV-specific IgG ELISA in 7 day culture supernatant from cultures of CXCR5⁺CXCR3⁺ T cells and memory B cells was also quantified. For (A)-(D) and (F) bars represent mean ±SD. Symbols on the graphs represent stage 1/2 individuals (black circles) and stage 3 individuals (black squares) and statistics were carried out using the Mann-Whitney non-parametric test. For (E) symbols represent stage 1/2 individuals (black circles) and stage 3 individuals (black squares) and correlation data was analyzed using Spearman r test. * P< 0.05. Results were significant if P < 0.05.