T cell surface glycoprotein CD45 (CD45)

T cell surface glycoprotein CD45 is a highly abundant, heavily glycosylated type I transmembrane protein expressed on all nucleated hematopoietic cells except erythrocytes and plasma cells[3][6]. It is the prototypical member of the receptor-like protein tyrosine phosphatase (RPTP) family and is essential for regulating antigen receptor-mediated signaling, especially in T cells[4][5]. CD45 functions as a critical "gatekeeper" for T cell receptor signaling by activating the Src family tyrosine kinase Lck, facilitating antigen discrimination, and tuning T cell responses[5]. Multiple isoforms are generated through alternative splicing, which allows for the subclassification of T lymphocytes and other immune cells[6]. Aberrant expression or dysfunction of CD45 is implicated in immune disorders, certain malignancies, and autoimmunity. It is a clinically significant marker in immunophenotyping and in specific conditioning regimens for stem cell transplantation.

Other names

Leukocyte common antigenProtein tyrosine phosphatase, receptor type C (PTPRC)Receptor-type protein tyrosine phosphatase CLCACD45RO (isoform)CD45RA (isoform)CD45RB (isoform)

Antibody-mediated depletion of CD45+ cells (e.g., radiolabeled anti-CD45 for myeloablation) Modulation of immune signaling via phosphatase inhibition or antibody binding