CD45, also known as protein tyrosine phosphatase receptor type C (PTPRC), is a transmembrane protein encoded by the PTPRC gene on chromosome 1q31-32. It is a critical regulator of immune cell function and development, consisting of approximately 1,258 amino acids with a molecular weight ranging from 180 to 220 kDa due to glycosylation. CD45 undergoes extensive post-translational modifications, including phosphorylation, glycosylation, and disulfide bond formation. As a transmembrane protein, CD45 is primarily localized to the plasma membrane of hematopoietic cells, where it plays essential roles in cell signaling, activation, and differentiation. The function of CD45 is central to immune cell biology, particularly in regulating the activation and signaling of T and B lymphocytes. CD45 acts as a key tyrosine phosphatase that modulates signaling pathways downstream of antigen receptors, cytokine receptors, and co-stimulatory molecules, thereby regulating immune cell activation, proliferation, and differentiation. CD45 helps maintain the balance of intracellular signaling cascades critical for immune cell responses by dephosphorylating specific tyrosine residues on signaling molecules.
CD45 is expressed on all nucleated hematopoietic cells, including T cells, B cells, natural killer cells, monocytes, macrophages, and granulocytes. Its expression levels vary across different immune cell subsets and developmental stages, with distinct isoforms of CD45 exhibiting cell-type-specific expression patterns. The expression of CD45 is tightly regulated during immune cell development and activation, with cytokines, growth factors, and cell-cell interactions influencing its expression levels and isoform distribution. Mutations in the PTPRC gene or dysregulation of CD45 expression have been associated with various immunodeficiency disorders, autoimmune diseases, and malignancies.
In clinical diagnostics, CD45 is routinely employed as a marker to identify hematopoietic lineage cells, aiding in the differentiation of hematopoietic malignancies from non-hematopoietic tumors through techniques like immunohistochemical staining. Moreover, CD45 expression levels or alterations in its pattern have been recognized to carry diagnostic and prognostic significance in various diseases, particularly cancer. In certain lymphomas and leukemias, aberrant CD45 expression or loss may signify disease aggressiveness or poor prognosis. Conversely, in solid tumors such as breast cancer and colorectal cancer, the presence of tumor-infiltrating lymphocytes expressing CD45 has been associated with more favorable prognoses and improved patient survival. Furthermore, the therapeutic implications of CD45 extend to immunotherapy, wherein targeting CD45-expressing immune cells, notably T cells, with immunomodulatory agents like checkpoint inhibitors has emerged as a promising approach in cancer treatment.
In therapeutic applications, CD45 has been explored as a potential target for immunotherapy, particularly in the context of hematological malignancies and autoimmune diseases. One study reported that an anti-CD45 antibody drug conjugate could target conditioning agents for stem cell transplantation with potent anti-leukemic properties.
NeoBiotechnologies offers a variety of antibodies against CD45 that have been validated for flow cytometry, immunofluorescence, immunohistochemistry, and Western blotting. Additionally, we hold exclusive rights to CD45 antibodies available for licensing or collaboration [https://www.neobiotechnologies.com/gene-name/ptprc/].
Synonyms
Receptor-type tyrosine-protein phosphatase C, Leukocyte common antigen, T200, B220, CD45R, GP180, Leukocyte common antigen (LCA), Loc, Ly-5, Lyt-4, Protein tyrosine phosphatase receptor type C (PTPRC), Receptor-type tyrosine-protein phosphatase C, T200 glycoprotein
Research Areas
Cancer, Developmental Biology, Immunology, B Cell Markers, Dendritic Cell Marker, Hematopoietic Stem Cells, Mesenchymal Stem Cell Differentiation
