engleski

Differential regulation of Type I cytokines/cytokine receptors on naive and memory B cells

B cells can be skewed to differentiate along "Type 1" or "Type 2" pathways and correspondingly impact upon the direction of an immune response. However, scant information is available on how this might be regulated. Here we showed that naive and memory tonsilar B cells are remarkably similar in their potential for IL-12 responses as revealed by basal and regulated expression of receptors for this initiating Type 1 cytokine. BCR-engagement provided a priming signal for the induction of IL-12R1 which can be potentiated by IFN-gamma and CD40 ; IL-12 itself prompted the down-regulation of its 1 receptor. IL-12R2, essentially absent on both naive and memory cells, was induced solely by IFN-gamma and then only on a minor subset of each. The expression of WSX-1, an orphan receptor for newly described IL-27, was higher on freshly isolated and non-activated cells. Comparing the potential of naive vs memory B cells for Type 1 cytokine production showed that CD40 ligation induced p40 IL-12, especially in memory cells ; neither subset secreted significant amounts of p70 IL-12. Memory B cells also expressed more p19 IL-23 mRNA with the major signal responsible for its production being BCR triggering. Thus, while B cell subpopulations seem to be limited in their capacity for initiating Type I responses, memory B cells exhibit the potential for their maintenance and amplification.

B-stanice; IL-12; IL-12R; reakcije tipa 1

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