Differentiation and apoptosis of human germinal center B-lymphocytes.
An in vitro experimental model was developed to characterize the cellular and molecular factors that regulate germinal center (GC)-B-cell differentiation and apoptosis. In the culture system that sustains the GC-B-cell survival, CD40L stimulation is essential for GC-B-cell proliferation and differentiation in the presence of 1L-2, IL-4, and IL-10. IL-2 and Il-4 promote proliferation of GC-B-cells, whereas IL-10 is required for generation of plasma cells. Generation of memory B cells requires CD40L, IL-2, IL-4, but not IL-10. There are two mechanisms that cause apoptosis. In the early stage, spontaneous apoptosis occurs in the absence of CD40 stimulation. Following CD40L stimulation, Fas-mediated apoptosis operates to eliminate GC-B-cells, unless activated GC-B-cells encounter a second signal via B-cell Ig receptors. Physiological significance of these findings is discussed.
Choi
Y S
YS
Alton Ochsner Medical Foundation, Laboratory of Cellular Immunology, New Orleans, LA 70121, USA. ychoi@ochsner.org
D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology*; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D018858:Germinal Center / Q000166:cytology*; D006801:Humans