Fibroblast-like synoviocytes from @entity309 patients express functional @entity8252 receptor complex: endogenous @entity8252 in autocrine fashion enhances cell proliferation and expression of @entity1836 and XXXX .

@entity3647 @entity588 @entity1356 @entity310 @entity8553 @entity1836 @entity8252 @entity44262 @entity309
The hallmarks of @entity309 ( @entity309 ) are leukocytic infiltration of the synovium and expansiveness of @entity8553 ( @entity8553 ). The abnormal proliferation of @entity8553 and their resistance to apoptosis is mediated, at least in part, by present in @entity309 joints proinflammatory cytokines and growth factors. Because @entity8252 exerts properties of antiapoptotic and growth factors, and is produced by @entity309 @entity8553 , we hypothesized that @entity8252 participates in @entity309 @entity8553 activation. To test this hypothesis, we first examined whether @entity309 @entity8553 express chains required for high affinity functional IL-15R. Indeed, @entity309 @entity8553 express @entity44262 at mRNA and protein levels. Moreover, we confirmed the presence of @entity3647 and common gamma-chains. Interestingly, @entity310 or @entity1356 triggered significant elevation of @entity44262 chain at mRNA and protein levels. Next, we investigated the effects of exogenous or endogenous @entity8252 on @entity588 and @entity1836 expression, @entity8553 proliferation, and apoptosis. Exogenous @entity8252 enhanced @entity309 @entity8553 proliferation and increased the level of mRNA-encoding @entity1836 . To test the role of endogenous @entity8252 in the activation of @entity309 @entity8553 , an @entity8252 mutant/Fcgamma2a protein exerting properties of specific antagonist to the @entity44262 chain was used. We found that blocking @entity8252 biological activities using this protein substantially reduced endogenous expression of @entity588 and @entity1836 (L), and @entity309 @entity8553 proliferation that was reflected by increased apoptosis. Thus, we have demonstrated that a distinctive phenotype of @entity309 @entity8553 , i.e., persistent activation, proliferation, and resistance to apoptosis, is related to the autocrine activation of IL-15Rs by @entity8553 -derived @entity8252 .
