CD38 and infection: During the various phases of infection, ECs demonstrated a markedly low-level expression of HLA-DR and CD38, considered as the markers of T-cell activation in CD4+ T cells from the acute to chronic infection phase (49, 84, and 133 days post-infection), which was also observed in CD8+ T cells specifically during the chronic infection phase (133 days post-infection, Fig. 2E and F).