Fig 3. Human tonsil CD8 TFR inhibit TFH and GC B cell function.
Tonsil cells were sorted to isolate CD8 TFR, CD8 conv, CD3+CD8-CXCR5+ TFH, and CD19+CD38+ GC B cells and X4- or R5-spinoculated. Cells were then co-cultured at indicated ratios for 2 days and analyzed. (A) IL-21 production by TFH with increasing (left to right) number of CD8 TFR (n = 4). (B) Representative examples from X4- and R5-spinoculations showing IL-21 production by TFH alone, 1:1 with CD8 TFR, 1:1 with CD8 TFR and anti-Tim3 antibody (500 ng/μl; right panels), and 1:1 with CD8 TFR and an isotype control antibody (500 ng/μl). (C) Results from a total of 6 tonsils (isotype n = 3) as described in B. (D) IgG production in X4-spinoculated cultures with 2.5 μg/mL CpG-B stimulation in CD8 TFR, TFH, and B cell co-cultures as measured by ELISA. All co-cultures are 1:1 (n = 7). Statistical significance was determined by non-parametric Wilcoxon matched-pairs tests (B) or one-way ANOVA (Friedman test, C) and is displayed as * = p<0.05, ** = p<0.01 and *** = p<0.001.