Fig. 4.

ATRA increases numbers of memory CD8⁺ T cells at mucosal sites in primed mice. Tissues were harvested from C57BL/6 mice on day 38 post-Ad5gp vaccination in the presence of vehicle or ATRA and analyzed for CD44 and tetramer binding of the gated CD8⁺ T cells (A), total numbers of gp33-specifc memory CD8⁺ T cells (B), histograms of CCR9 expression (C), and frequencies of CCR9^hi cells in gated gp33/D^b+ CD44^hi CD8⁺ T cells. The filled area in panel C indicates CD44^low CD8α⁺ T cells from the same tissues. Numbers in panels A and C represent mean values for 3 to 5 mice in each group from one of two repeated experiments.