B cells from aged mice exibit reduced apoptosis upon BCR stimulation and differential ability to up-regulate survival signals

C. MONTES, B. MALETTO, E. ACOSTA, A. GRUPPI, M. C. PISTORESI.

CLINICAL AND EXPERIMENTAL IMMUNOLOGY

Año: 2005 vol. 143 p. 30 - 40

0009-9104

During ageing, autoimmune disorders and the higher susceptibility to infectious have been associated with alterations in the humoral immune response. We report that splenic B lymphocytes from aged mice exhibit lower level of apoptosis induced by B-cell antigen receptor (BCR) ligation in vitro . Respect to B cells from young mice the anti-ì stimulated aged B cells show similar Bcl-2 and Bcl-xL expression but differential kinetic of A1 degradation and a higher level of cFLIP and FAIM. Even though B cells from aged mice show minor Fas expression they exhibit the same susceptibility to anti-Fas induced apoptosis. Aged B cells also present upon BCR stimulation, a higher proliferative response and similar level of activation markers expression than B cells from young mice. These data agree with the observation that aged mice exhibit an increment of T2 and mature B cell subset which rapidly enters cell cycle upon BCR engagement. The diminished apoptosis after activation in aged mice could compromise homeostatic mechanism allowing the persistence of self and non-self antigen specific B cells.