FIGURE 7.
SLAM-deficient GC TFH cells exhibit impaired IL-4 production. A, Flow cytometric analysis of SLAM expression on naive CD4 T cells and in vitro polarized TH1 and TH2 CD4 T cells. B, Flow cytometric analysis of SLAM and CXCR5 expression on CD45.1+ SMtg CD4 T cells, day 8 after LCMV infection. C, Microarray analysis of SLAM mRNA in naive (CD44lo, from uninfected mice), non-TFH (CXCR5lo), and TFH (CXCR5hi) SMtg CD4 T cells. D and E, Flow cytometry on splenocytes, day 8 after LCMV infection of B6 mice. D, SLAM expression on naive (CD44lo), non-TFH (CD44hi CXCR5lo), TFH (CD44hiCXCR5loGL7−), and GC TFH (CD44hiCXCR5+GL7+) endogenous CD4 T cells. E, SLAM mean fluorescence intensity (MFI), quantified from experiments in D. F, SLAM MFI on IgD+ (naive) and GC B cells, day 8 after LCMV infection of B6 mice. Data are representative of three to five independent experiments. G, GC TFH (CXCR5hiGL7+), TFH (CXCR5hiGL7−), and non-TFH (CXCR5−/lo) CD4 T cell populations in Slamf1−/− (SLAM−/−) and Slamf1+/+ (SLAM+/+) mice, 8 d after LCMV infection. Gated CD44hiCD4+ T cells are shown. Quantitated TFH cell (H) and GC TFH cell (I) frequencies in SLAM+/+ and SLAM−/− mice, from experiment shown in G (n = 6/group). Data are representative of three independent experiments. J and K, GC TFH, TFH, and non-TFH CD4 T cells, as gated in G, were sorted from SLAM −/− and SLAM+/+ mice, 8 d after LCMV infection. Expression of IL-4 (J) and IL-21 (K) mRNA in SLAM+/+ and SLAM−/− GC TFH cells. Expression levels by qPCR were quantitated in reference to a control gene and then normalized to naive CD4 T cells. Data are representative of two experiments (n = 3/group). **p < 0.01; ***p < 0.001.