ABSTRACT
T cells but is absent or of low density on
γδ
T cells. It has been discovered on many murine B cell lymphomas as well as on endothelial cells of blood vessels in the pregnant sheep uterus. CD72 on B cells is one of its three ligands. CD5 is present on thymocytes and most peripheral T cells. It is believed to be significant for the activation of T cells and possibly B1 cells. CD5 is also present on a subpopulation of B cells termed B1 cells that synthesize polyreactive and autoreactive antibodies as well as the “natural antibodies” present in normal serum. Human chronic lymphocytic leukemia cells express CD5, which points to their derivation from this particular B cell subpopulation.
