CD4 and infection: More interestingly, we found that a CD8high+ population increased in peripheral blood mononuclear cells (PBMCs) from ALV-J infected chickens compared to control chickens at 21 days post-infection (DPI), which then formed three stable populations of CD8+ T lymphocytes in the infected chickens, including CD8 high+, CD8medium+, and CD4+CD8low+cells (Dai et al., 2020).