Early events in human B cell activation: metabolic pathways vary according to the first signal used
✍ Scribed by Bernard Dugas; Aimé Vazquez; Bernard Klein; Jean-Francois Delfraissy; Marietherese Rammou; Jean-Philippe Gerard; Pierre Galanaud
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 653 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0014-2980
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✦ Synopsis
Early events in human B cell activation: metabolic pathways vary according to the first signal used*
The effects of the calcium channel blocking drug Verapamil and of palmitoyl-carnitin (PTC), an inhibitor of protein-kinase C activity, on human B cell activation were measured. Both Verapamil and PTC inhibited the B cell proliferation induced by costimulation with anti-p antibody and with 3 different growth factors: interleukin 2, 20-kDa B cell growth factor and 50-kDa B cell growth factor. Both uridine and thymidine incorporation induced by costimulation with ionomycin and phorbol 12myristate 13-acetate (PMA) were inhibited by Verapamil and PTC. In contrast, B cell proliferation was resistant to Verapamil (while being still inhibited by PTC) in two situations: (a) when B cells were costimulated with PMA and growth factors and (b) when B cells previously activated in vitro (by anti-y antibody or PMA) were stimulated with growth factors. These results confirm that the late stage (G, -+ S transition) of B cell activation is independent of Ca2+ entry. More importantly, they show that the initial events induced by anti-p, antibody and by PMA are based on different biochemical pathways: PMA would act on a subpopulation of B cells which has already received an early signal of activation in vivo. This emphasizes the functional and biochemical heterogeneity of the Go stage among circulating B cells.