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Generation of Human CD40-activated B cells
13:27

Generation of Human CD40-activated B cells

Published on: October 17, 2009

Up-regulation of Bcl-xL expression protects CD40-activated human B cells from Fas-mediated apoptosis

X Zhang1, L Li, J Choe

  • 1Laboratory of Cellular Immunology, Alton Ochsner Medical Foundation, New Orleans, Louisiana 70121, USA.

Cellular Immunology
|October 10, 1996
PubMed

CD40--CD40L interactions between resting B cells and activated T cells are essential for germinal center formation. It has been shown that CD40L can induce both Fas expression and susceptibility to Fas-mediated killing in B cells, while anti-Ig can partially rescue B cells from Fas-mediated killing. However, the intracellular mechanism for this phenomenon is not known. We examined the expression of Fas and bcl-2 family gene products, such as Bcl-2, Bcl-x, Bax, and Mcl-1, in human tonsillar B cells. The activation of naive B cells by CD40L induced transient expression of Bcl-xL. As the Bcl-xL level decreased in CD40-activated B cells, the cells became susceptible to apoptosis by anti-Fas antibodies. Though anti-Ig did not change the Fas expression, it protected CD40-activated B cells from Fas-mediated killing by up-regulating Bcl-xL expression. The addition of anti-Ig did not significantly change Bcl-2, Bax, and Mcl-1 levels compared to those of B cells activated by CD40L alone.

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