The CD45 tyrosine phosphatase regulates Campath-1H (CD52)-induced TCR-dependent signal transduction in human T cells

The CD45 tyrosine phosphatase regulates Campath-1H (CD52)-induced TCR-dependent signal transduction in human T cells.

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...

TCR signal transduction in antigen-specific memory CD8 T cells.

Memory T cells are more responsive to Ag than naive cells. To determine whether memory T cells also have more efficient TCR signaling, we compared naive, effector, and memory CD8 T cells of the same antigenic specificity. Surprisingly, initial CD3 signaling events are indistinguishable. However, memory T cells have more extensive lipid rafts with higher phosphoprotein content before TCR engagem...

In TCR-Stimulated T-cells, N-ras Regulates Specific Genes and Signal Transduction Pathways

It has been recently shown that N-ras plays a preferential role in immune cell development and function; specifically: N-ras, but not H-ras or K-ras, could be activated at and signal from the Golgi membrane of immune cells following a low level T-cell receptor stimulus. The goal of our studies was to test the hypothesis that N-ras and H-ras played distinct roles in immune cells at the level of ...

Activation of tyrosine phosphorylation in human T cells via the CD2 pathway. Regulation by the CD45 tyrosine phosphatase.

In this study we compare the effect of CD3 and CD2 ligation on tyrosine kinase activation in human peripheral blood T cells. Using antiphosphotyrosine antibody to detect tyrosine phosphorylation of cellular substrates, we demonstrate that mAb stimulation of either CD3 or CD2 results in tyrosine phosphorylation of the TCR-zeta chain and 135- and 100-kDa proteins. However, differences are observe...

Protein Tyrosine Phosphatase That Lack Catalytically Active PTPN3 Normal TCR Signal Transduction in Mice