The PTPRC antibody targets the protein tyrosine phosphatase receptor type C (PTPRC), commonly known as CD45 or leukocyte common antigen (LCA). This transmembrane glycoprotein is a receptor-type tyrosine phosphatase expressed exclusively on nucleated hematopoietic cells, including T and B lymphocytes, natural killer cells, monocytes, and granulocytes. It plays a crucial role in immune cell signaling by regulating antigen receptor signaling through the dephosphorylation of Src-family kinases, thereby modulating lymphocyte activation, differentiation, and survival.
Structurally, CD45 contains a cytoplasmic phosphatase domain and an extracellular domain with variable isoforms generated by alternative splicing of exons 4-6 (A, B, and C). These isoforms (e.g., CD45RA, CD45RO) serve as markers for distinguishing naive and memory T-cell subsets. The PTPRC gene is located on chromosome 1q31-q32.
PTPRC antibodies are widely used in research and diagnostics to identify immune cell populations via flow cytometry, immunohistochemistry, or Western blot. They are essential in studying immune dysregulation, including autoimmune diseases (e.g., multiple sclerosis), leukemia/lymphoma classification (CD45 absence helps identify immature blasts), and HIV pathogenesis. Additionally, CD45 expression patterns aid in monitoring immune reconstitution post-transplant or during immunotherapy. Its conserved structure across mammals makes it a valuable cross-species marker.