CD45, a receptor-like protein tyrosine phosphatase (PTP), plays an essential role in lymphocyte development and immune responses. Recent evidence suggests that dimerization of CD45 downregulates its function. However, the mechanisms by which CD45 dimerization is regulated remain unclear and there is no direct evidence that the PTP activity of CD45 dimers is less than that of monomers. CD45 in l...

CD45, a receptor-like protein tyrosine phosphatase (PTP), plays an essential role in lymphocyte development and immune responses. Recent evidence suggests that dimerization of CD45 down-regulates its function. However, the mechanisms by which CD45 dimerization is regulated remain unclear, and there is no direct evidence that the PTP activity of CD45 dimers is less than that of monomers. CD45 in...

CD45, a receptor-like protein tyrosine phosphatase (PTP), plays an essential role in lymphocyte development and immune responses. Recent evidence suggests that dimerization of CD45 downregulates its function. However, the mechanisms by which CD45 dimerization is regulated remain unclear, and there is no direct evidence that the PTP activity of CD45 dimers is less than that of monomers. CD45 in ...

CD45-AP specifically associates with CD45, a protein tyrosine phosphatase essential for lymphocyte differentiation and antigen receptor-mediated signal transduction. CD45 is thought to mediate antigen receptor signaling by dephosphorylating regulatory tyrosine residues on Src family protein tyrosine kinases such as Lck. However, the mechanism for regulating CD45 protein tyrosine phosphatase act...

Recently, there has been an increasing interest in the expression pattern and biological significance of the CD45 molecule in myeloma cells. In this study, we have further defined the phenotypic pattern of CD45 expression on myeloma cells. Using a panel of myeloma cell lines, we showed that CD45 showed a remarkably heterogeneous pattern of expression. Whereas some cell lines were CD45(+) and ot...

Galectin-1 induces death of immature thymocytes and activated T cells. Galectin-1 binds to T cell-surface glycoproteins CD45, CD43, and CD7, although the precise roles of each receptor in cell death are unknown. We have determined that CD45 can positively and negatively regulate galectin-1-induced T cell death, depending on the glycosylation status of the cells. CD45(+) BW5147 T cells lacking t...

Expression of the CD45 Ag in hemopoietic cells is essential for normal development and function of lymphocytes, and both mice and humans lacking expression exhibit SCID. Human genetic variants of CD45, the exon 4 C77G and exon 6 A138G alleles, which alter the pattern of CD45 isoform expression, are associated with autoimmune and infectious diseases. We constructed transgenic mice expressing eit...

CD45 is a leukocyte-specific protein tyrosine phosphatase and an important regulator of AgR signaling in lymphocytes. However, its function in other leukocytes is not well-understood. In this study, we examine the function of CD45 in dendritic cells (DCs). Analysis of DCs from CD45-positive and CD45-null mice revealed that CD45 is not required for the development of DCs but does influence DC ma...

The present study showed that the HIS-C7 monoclonal antibody, which recognizes the chick form of CD45, is a specific marker for macrophages/microglial cells in the developing and mature chick central nervous system (CNS). HIS-C7-positive cells were characterized according to their morphological features and chronotopographical distribution patterns within developing and adult CNS, similar to th...