Receptor-type tyrosine-protein phosphatase C isoform CD45RA (CD45RA)

CD45RA is a specific isoform of the receptor-type tyrosine-protein phosphatase C (PTPRC, also known as CD45), a type I transmembrane glycoprotein that plays a fundamental role in the immune system. CD45RA (the RA isoform) is generated by alternative splicing and contains exon 4, giving rise to a 205–220 kDa protein. It is expressed predominantly on naive T cells, medullary thymocytes, B cells, and monocytes, where it modulates T-cell and B-cell antigen receptor signaling by regulating the phosphorylation of key signaling proteins (e.g., Src-family kinases, JAK kinases). CD45RA is widely used as a biomarker in flow cytometry to discriminate naive from memory T cells (the latter usually express CD45RO, another isoform). It is critical for effective immune responses, immune cell homeostasis, and is utilized clinically to evaluate immune cell subsets and diagnose hematological malignancies. While not considered a direct therapeutic drug target, its diagnostic and research utility is extensive, and its broad expression across the immune system poses risks for generalized immunosuppression should it become a therapeutic target[1][3][4][5][6][8].

Other names

Receptor-type tyrosine-protein phosphatase C isoform 6CD45RA antigenLeukocyte common antigen RALCA-RAGP180L-CALCALY5T200PTPRC

- Antibody-mediated cell identification and sorting (e.g., flow cytometry) - Antibody-mediated cell depletion in research/bone marrow transplantation - Potential immunosuppression via targeting of CD45-expressing cells (experimental)