CD45 EXPRESSION BY MURINE B-CELLS AND T-CELLS - ALTERATION OF CD45 ISOFORMS IN SUBPOPULATIONS OF ACTIVATED B-CELLS

The CD45 family of high molecular weight cell surface glycoproteins is abundantly expressed by virtually all hematopoietic cells. CD45 molec ules exist as multiple isoforms whose extracellular portions vary in p rotein structure and carbohydrate content but whose intracellular port ions are highly conserved and possess tyrosine phosphatase activity. I n this review we summarize current studies describing CD45 isoform exp ression on peripheral and thymic lymphocytes. Further, we analyze chan ges in CD45 isoform expression by selective populations of activated B cells.