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pubmed:abstractText |
CD45, a hematopoietic cell-specific surface antigen, has recently been shown to be a protein tyrosine phosphatase. Expression of CD45 is essential for the T-cell antigen receptor to couple with the phosphatidylinositol second messenger pathway and for antigen-mediated proliferation of T lymphocytes. In this report we describe a CD45-deficient mutant of the human T-cell leukemia line Jurkat. CD45 expression is required for the activation of a T-cell receptor-associated tyrosine kinase as well as the phosphatidylinositol pathway. Additionally, stimulation of T lymphocytes by way of the accessory molecule CD2 requires the expression of CD45. The mutation in the CD45-deficient cell specifically impairs signal transduction by the T-cell receptor and CD2 because activation events by way of another accessory molecule, CD28, are unimpaired.
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