Switch in the protein tyrosine phosphatase associated with human CD100 semaphorin at terminal B-cell differentiation stage.

摘要: Human CD100, the first semaphorin identified in immune system, is a transmembrane protein involved T-cell activation. In present study, we showed that activation of peripheral blood or tonsillar B lymphocytes induced expression CD100 CD38+CD138− cell populations, including CD148+ subpopulations, thus expressing memory B-cell–like phenotype. Using an vitro enzymatic assay, found tyrosine phosphatase (PTP) activities were immunoprecipitated with these which isolated by sorting, as well most B-cell lines representing various stages differentiation. Immunodepletion and Western blotting experiments demonstrated CD45 was PTP associated displaying pre-B, activated B, pre-plasma phenotypes. also accounted for activity cells sorted after lymphocytes. contrast, no CD100-CD45 association observed plasma corresponding to terminal differentiation stage. CD148, other known be implicated lymphocyte signaling pathways, either only partly CD100-associated not expressed lines, indicating another main PTP. Our data show differentially can functionally associate distinct PTPs depending on their maturation state. They provide evidence switch at stage