Loss of surface antigens is a conserved feature of apoptotic lymphocytes from several mammalian species.

Human lymphocytes lose the expression of lineage antigens (LAgs) along apoptosis. Our aim was to extent our previous studies of LAg loss to rodent species, quantifying LAg expression on apoptotic murine lymphocytes using flow cytometry to measure alterations in cell permeability, phosphatidylserine exposure and caspase activation of CD3, CD5, CD4, CD8, CD19 and CD28 LAgs in highly purified lymphocyte populations. We found loss of expression by apoptotic cells of all LAgs studied in the three species analyzed except for CD3 antigen in mouse. We also found an early, rapid and dramatic reduction in the expression of CD28 by early apoptotic cells. We found several homologies across the three species in the kinetic of loss of several LAgs such as CD5, CD4 and CD28. These data suggest that the loss of expression of LAgs by apoptotic lymphocytes is a common and conserved feature of lymphocytes undergoing apoptosis in several mammalian species.