Interaction between Src homology 2 domain bearing protein @entity669 phosphatase substrate-1 and @entity28223 mediates the adhesion of XXXX B lymphocytes to nonactivated endothelial cells.

@entity1 @entity28224 @entity28223 @entity669 @entity4357
@entity28223 modulates a variety of cell functions such as adhesion, spreading, and migration. Using a fusion protein consisting of the extracellular region of Src homology 2 domain bearing protein @entity669 phosphatase substrate-1 ( @entity28224 ) and the Fc portion of @entity1 Ig ( @entity28224 -Ig) we investigated the effects of @entity28224 as a ligand for @entity28223 on B lymphocytes. Although @entity28224 -Ig binding to @entity1 B cell lines was solely mediated via @entity28223 , their binding capacity for soluble and immobilized @entity28224 -Ig varied among cell lines irrespective of the similar expression levels of @entity28223 , suggesting that distinctive affinity/avidity states exist during B cell maturation. @entity1 cell line and tonsilar B lymphocytes adhered to immobilized @entity28224 -Ig and showed polarization-like morphology. These effects of @entity28224 -Ig were blocked by anti- @entity28223 mAbs (B6H12 and SE5A5). Wortmannin, a @entity4357 -3 kinase inhibitor, but not pertussis toxin significantly inhibited the polarization induced by the immobilized @entity28224 -Ig. Thus, @entity28224 acts as an adhesive substrate via @entity28223 in @entity1 B lymphocyte. Immunohistochemical analyses indicated that @entity28224 is expressed on high endothelial venule as well as macrophages in @entity1 tonsils. HUVECs also express @entity28224 in the absence of any stimuli, and the adhesion of tonsilar B lymphocytes to nonactivated HUVECs was significantly inhibited by SE5A5, indicating that @entity28224 / @entity28223 interaction is involved in the adhesion. Our findings suggest that @entity28224 / @entity28223 interaction may contribute to the recruitment of B lymphocytes via endothelial cells under steady state conditions.
