Protein tyrosine phosphatase receptor type C isoform CD45RA (CD45RA)

Protein tyrosine phosphatase receptor type C isoform CD45RA is a high-molecular-weight transmembrane glycoprotein and a member of the protein tyrosine phosphatase (PTP) family [1, 6]. It is an alternative splicing product of the PTPRC gene, specifically containing the A exon, and is primarily expressed on naive T cells, B cells, and a subset of effector memory T cells (TEMRA) [9, 12]. CD45RA plays an essential role in regulating the threshold of T-cell activation by dephosphorylating the inhibitory tyrosine of Src family kinases, such as Lck and Fyn, thereby facilitating T-cell receptor signaling [2, 12]. In clinical medicine, CD45RA is a key biomarker for distinguishing naive T cells from memory T cells and for identifying leukemic stem cells in acute myeloid leukemia [7, 8]. Therapeutic interventions targeting CD45RA include the selective depletion of CD45RA+ cells from hematopoietic stem cell grafts to reduce the risk of graft-versus-host disease while maintaining anti-pathogen immunity [14, 15]. Furthermore, CD45RA-targeted immunotoxins and antibodies are under investigation for the treatment of refractory leukemias [7].

Other names

CD45RLeukocyte common antigenLCAT200B220

CD45RA functions as a receptor-type protein tyrosine phosphatase that dephosphorylates the inhibitory C-terminal tyrosine of Src family kinases, such as Lck and Fyn, to initiate and regulate T-cell receptor signaling. Therapeutic strategies targeting this isoform include the selective depletion of CD45RA+ naive T cells from donor grafts to prevent graft-versus-host disease (GVHD) while preserving memory T-cell immunity, and the use of targeted immunotoxins to induce cell death in CD45RA-expressing leukemic stem cells.