Differential responses to Ig and class II-mediated signals in splenic B cell subsets from normal and autoimmune XXXX .

@entity19 @entity1 @entity23341 @entity58
B cells of @entity19 and @entity1 can be divided into distinct subpopulations, differing in distribution and phenotype. It is not known, however, whether B cell subsets respond similarly to signals mediated by cognate interactions with T cells, such as ligation of the B cell class II MHC molecule. @entity19 splenic B cells proliferate in response to a combination of non-mitogenic anti-mu mAb, @entity58 and class II MHC-specific mAbs. In order to assess the response of B cell subpopulations to these signals, B cells were separated on the basis of @entity23341 expression. Previous studies have shown that @entity23341 expression is useful in distinguishing marginal zone from follicular B cells and peritoneal B1 from B2 B cells. B cells of both subsets responded to the combination of signals, but @entity23341 - B cells showed a higher response. Splenic B cells were also purified from several strains of autoimmune @entity19 , of interest because their disease features expansion of @entity23341 - B cells and autoantibody production. While normal B cells showed no response to non-mitogenic anti-mu mAb alone, B cells from autoimmune @entity19 showed a marked decrease in proliferation. Addition of @entity58 plus class II-specific mAbs restored increased proliferation. Again, responses were higher in @entity23341 - than in @entity23341 + B cells. These findings suggest that @entity23341 - B cells are especially responsive to signals delivered through class II and the @entity58 receptor. These signals may allow preferential rescue of @entity23341 -B cells from antigen-mediated tolerance and result in their hyperexpansion in response to autoreactive T cells.
