Protein tyrosine phosphatase, receptor type C (CD45)

CD45 (protein tyrosine phosphatase, receptor type C; PTPRC) is a large, highly glycosylated transmembrane glycoprotein uniquely expressed on all nucleated hematopoietic cells except erythrocytes and plasma cells[3][5]. It is the prototypical member of the receptor-like protein tyrosine phosphatase family[1][2]. CD45 serves essential roles in lymphocyte development and immune response by tightly regulating antigen receptor signal transduction via dephosphorylation of Src family kinases (e.g., Lck and Fyn in T cells)[2][3][5]. Multiple isoforms arise due to alternative splicing, conferring cell subtype- and activation stage-specific functions[4][5]. CD45 is a widely used pan-leukocyte marker in diagnostics and research[5], and, due to its broad hematopoietic expression, represents a highly effective, but non-specific, therapeutic target for conditioning regimens and experimental immunosuppression. However, global targeting leads to depletion of most immune cell populations, posing significant safety risks including immunodeficiency[5].

Other names

Leukocyte common antigenPTPRCT200B220 (on B cells)CD45RACD45ROCD45RBCD45RABCCD45RABLy5

Monoclonal antibodies: Depletion of CD45-expressing cells via antibody-dependent cell-mediated cytotoxicity or complement-dependent cytotoxicity. Targeted radioconjugates: Deliver radiation to CD45+ cells for bone marrow ablation.