Related Experiment Video
Updated: Sep 26, 2026

Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
IL-21 induces the apoptosis of resting and activated primary B cells
Devangi S Mehta1, Andrea L Wurster, Matthew J Whitters
1Department of Immunology and Infectious Diseases, Harvard School of Public Health, and Genetics Institute, Wyeth Research, Cambridge, MA 02140, USA.
Abstract:
Cytokines play an important role in regulating the development and homeostasis of B cells by controlling their viability. In this study, we show that the recently described T cell-derived cytokine IL-21 induces the apoptosis of resting primary murine B cells. In addition, the activation of primary B cells with IL-4, LPS, or anti-CD40 Ab does not prevent IL-21-mediated apoptosis. The induction of apoptosis by IL-21 correlates with a down-regulation in the expression of Bcl-2 and Bcl-x(L), two antiapoptotic members of the Bcl-2 family. Furthermore, the reconstitution of Bcl-x(L) or Bcl-2 expression protects primary B cells from IL-21-induced apoptosis. In addition, a short-term preactivation of B cells with anti-CD40 Ab confers protection from IL-21-mediated apoptosis through the up-regulation of Bcl-x(L). These studies reveal a novel pathway that mediates B cell apoptosis via the IL-21R and suggest that IL-21 may play a role in regulating B cell homeostasis.
Related Concept Videos
B Cell Activation and Differentiation
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...
The Intrinsic Apoptotic Pathway
Cells of the Adaptive Immune Response
Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
The Extrinsic Apoptotic Pathway
T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...

