Protein tyrosine phosphatase receptor type C (CD45RO isoform) (CD45RO)

Protein tyrosine phosphatase receptor type C (CD45RO isoform) is a transmembrane glycoprotein and a member of the protein tyrosine phosphatase (PTP) family (UniProt P08575). It is the shortest isoform of the CD45 molecule, resulting from the alternative splicing of exons 4, 5, and 6, and is characteristically expressed on the surface of memory and activated T lymphocytes (PubMed: 12414722). CD45RO plays a critical role in the immune system by regulating the phosphorylation state of Src-family kinases, such as Lck, which is essential for initiating T-cell receptor (TCR) signaling (Annual Review of Immunology, 2003). By maintaining these kinases in an active state, CD45RO lowers the threshold for T-cell activation, allowing memory cells to respond rapidly to previously encountered antigens. In clinical medicine, CD45RO+ memory T cells are implicated in the pathogenesis of autoimmune diseases and graft-versus-host disease (GVHD), making the CD45RO protein a target for selective depletion therapies (Blood, 2000). Experimental approaches using anti-CD45RO antibodies or immunotoxins seek to eliminate these reactive memory cells to treat chronic inflammation and transplant rejection while sparing the naive T-cell population (NCBI Bookshelf: NBK554420).

Other names

PTPRCCD45Leukocyte common antigenLCAT200Ly-5B220

Selective depletion of memory T cells via antibody-dependent cellular cytotoxicity (ADCC) or immunotoxin-induced apoptosis, and modulation of T-cell receptor signaling thresholds.