Figure 3. Distribution of T_FH cells and B cell subsets in mucosal tissues and lymphoid organs.

(a) Representative flow cytometry dot plots of CXCR5 and PD-1 expression on memory CD4⁺ T cells showing the distribution of CXCR5⁺PD-1⁺⁺, CXCR5⁺PD-1⁺, and CXCR5⁺PD-1⁻ CD4⁺ T cells. Cells were gated for hCD45 and Aqua LIVE/DEAD then gated for CD3 followed by gating on CD8⁺ and CD4⁺ T cells. CD4⁺ T cells were further gated on CD45RA negative cells. The gated CD4⁺ CD45RA⁻ T cells were then analyzed for PD-1 and CXCR5 expression. The frequency of CD4⁺ T cell subsets is shown. (b) Distribution of B cell subsets. B cells (hCD45⁺CD19⁺ cells) were stained for IgD and CD38. Naive (CD38⁻ IgD⁺), pre-germinal center B cells (CD38⁺ IgD⁺), germinal center (CD38⁺⁺ IgD⁻), early memory (CD38⁺ IgD⁻), late memory B cells (CD38⁻ IgD⁻), and plasma cells (CD38⁺⁺⁺ IgD⁻) are shown in the various tissues analyzed. The numbers represent the frequency of each subset. PC = plasma cells, M = memory B cells, pGC = pregerminal, and GC = germinal center B cells. The experiment was done 3 times for both (a) and (b).