Reactive microglia have been suggested to play a role in the Alzheimer's disease (AD) process, and previous studies have shown that expression of CD45, a membrane-bound protein-tyrosine phosphatase (PTP), is elevated in microglia in AD brain compared with controls. To investigate the possible role of CD45 in microglial responsiveness to beta-amyloid (Abeta) peptides, we first co-treated primary...

The CD45 antigen is present on all cells of the hematopoietic lineage. Using a murine model, we have determined whether a lytic CD45 monoclonal antibody can produce persistent aplasia and whether it could facilitate syngeneic or allogeneic stem cell engraftment. After its systemic administration, we found saturating quantities of the antibody on all cells expressing the CD45 antigen, both in ma...

Dear Editor, Somatic cells can be reprogrammed into totipotent or pluripotent state by nuclear transfer (NT) or the ‘Yamanaka method’. White adipose tissue (WAT) is a source of readily accessible donor cells that provide virtually unlimited cells for reprogramming. Recently, freshly isolated white adipose tissue-derived cells (ADCs) from humans or mice have been successfully reprogrammed into i...

Campath-1H, a humanized mAb undergoing clinical trials for treatment of leukemia, transplantation and autoimmune diseases, produces substantial lymphocyte depletion in vivo. The antibody binds to CD52, a highly glycosylated molecule attached to the membrane by a glycosylphosphatidylinositol anchor. Cross-linked Campath-1H is known to activate T cells in vitro. We have investigated the molecular...

The human CD45 gene encodes five isoforms of a transmembrane tyrosine phosphatase that differ in their extracellular domains as a result of alternative splicing of exons 4–6. Expression of the CD45 isoforms is tightly regulated in peripheral T cells such that resting cells predominantly express the larger CD45 isoforms, encoded by mRNAs containing two or three variable exons. In contrast, activ...

T lymphocytes express a tyrosine protein kinase (TPK; protein-tyrosine kinase; ATP:protein-tyrosine O-phosphotransferase, EC 2.7.1.112), pp56lck that is encoded by the lck protooncogene. This TPK was recently found to be associated with the intracellular domain of the T-cell surface glycoproteins, CD4 and CD8, suggesting that it plays an important role in T-cell development and activation. We h...

CD45 encodes a trans-membrane protein-tyrosine phosphatase expressed in diverse cells of the immune system. By combinatorial use of three variable exons 4-6, isoforms are generated that differ in their extracellular domain, thereby modulating phosphatase activity and immune response. Alternative splicing of these CD45 exons involves two heterogeneous ribonucleoproteins, hnRNP L and its cell-typ...

The CD45 antigen is a haemopoietic cell specific tyrosine phosphatase essential for antigen receptor mediated signalling in lymphocytes. Expression of different patterns of alternatively spliced CD45 isoforms is associated with distinct functions. We recently identified a polymorphism in exon 6 (A138G) of the gene encoding CD45 (PTPRC) that results in altered CD45 splicing. The 138G allele is p...

Murine very small embryonic-like (VSEL) cells, defined by the Lin(-)Sca-1(+)CD45(-) phenotype and small size, were described as pluripotent cells and proposed to be the most primitive hematopoietic precursors in adult bone marrow. Although their isolation and potential application rely entirely on flow cytometry, the immunophenotype of VSELs has not been extensively characterized. Our aim was t...