Fig. 1.

Macaques display substantial inter-individual variability in Th17 cell populations. (A) Th17 cells in peripheral blood, as assessed by the fraction of cells containing intracellular IL-17 after stimulation with PMA and ionomycin in the presence of brefeldin A. Diamond symbols represent animals with unusually large Th17 populations, as defined below; open circles represent one animal with an unusually small Th17 population, also as defined below. These symbols are used for these same three animals throughout Figure 1. The p value shown for tracking (longitudinal stability of a certain measurement in an individual over time) was calculated using the procedure outlined by Twisk (18) and detailed in Methods. At a minimum of three out of four time points, the three animals marked with diamonds and open circles had Th17 cell levels that were outside the 99.5% confidence interval for the group mean. (B) Tregs in the peripheral blood, as assessed by flow cytometric detection of cells that were CD3⁺CD4⁺CD8⁻CD25⁺CD127^low (see Figure S3C and refs. 16 and 41). (C) Th17 cells in peripheral blood as a fraction of CD4⁺ memory T cells (CD45RA⁻). (D) Th17 cells in CD4⁺ LNMC of six animals, sampled on two occasions that were two months apart. (E) Relationship between circulating and lymph node Th17 cell populations in uninfected and SIV-infected animals (filled and open circles, respectively). The regression lines, p value, and coefficient of determination shown are for one linear regression that accommodates the different slopes observed before and after infection; pre- and post-infection data were both included in the statistical analysis. Separate analyses on pre- and post-infection data also yielded significant correlations (p < 0.0001 in each case; R²=0.93 and 0.59). (F) Relationship between circulating and colon-resident Th17 cell populations in uninfected and SIV-infected animals (filled and open circles, respectively). Separate analyses on pre- and post-infection data also yielded significant correlations (p < 0.01 and p < 0.001, respectively; R²=0.88 and 0.53). (G) IL-17 expression in unstimulated CD4⁺ cells in PBMC or colon-resident lymphocyte populations, as assessed by intracellular cytokine staining and flow cytometry. The p value is from the Mann-Whitney U test. (H) Flow cytograms demonstrating IL-17 expression in unstimulated CD4⁺ T cells from colonic biopsy tissue. (I) Relationship between IL-17 production in unstimulated colon lymphocytes and in PBMC stimulated with PMA/ionomycin. The p value is for linear regression (p=0.003, R²=0.91).