Consequently, the number of splenic Ag-experienced (Ag-exp) CD11a+CD49d+ CD4+ T cells, which contain parasite-specific CD4+ T cell populations (22, 44), was significantly attenuated in mice with a CD4 T cell–specific mTOR deficiency on days 5 and 15 of infection (Fig. 1C). Here, ITGA4 is linked to infection.