Apoptosis in peripheral CD4+T cells and thymocytes by Marek's disease virus-infection.

Histological study revealed that Marek's disease virus (MDV) can cause apoptosis in peripheral blood lymphocytes (PBL) in latently infected chickens. Analysis of DNA fragmentation indicated that CD4+T cells but not CD8+T cells underwent apoptosis. These apoptotic changes were also observed in the thymus during the acute phase of the infection. Flow cytometry analysis showed the drastic decrease of CD4+CD8+ thymocytes, indicating that MDV can induce apoptosis in CD4+CD8+ immature thymocytes in acutely infected chickens. These changes might be involved in the immuno-suppression induced by MDV.