Figure 2.

CD45 isoform expression on human erythroid, lymphoid and myeloid haemopoietic cells at various stages of differentiation. RA, expressed on naïve T cells, has exon four with deficiency in exon 5 and 6. RB has only exon 5, expressed mainly on B cells, naïve T cells and thymocytes. RBC, has exons 5 and 6 of the CD45 gene. RABC, has all of the three exons 4, 6, and 6. RO, expressed on granulocytes, activated and memory T cells, some B subsets and activated monocytes/macrophages, has exon 3, 7 and 8 with deficiency in RA, RB and RC exons of the CD45 gene. ‘+’ means brighter expression (modified from Craig et al).⁸ NK, natural killer.