engleski

Type I Cytokine Profiles of Human B Lymphocyte Subcompartments: A Potential for Memory Cells to Impact Polarization

B cells bifurcating along ‘ type 1’ or ‘ type 2’ pathways under the influence of polarizing cytokines can, in turn, influence the direction of an immune response. Here, we compare the capacity of human B cells residing within naive and memory compartments to participate in type 1 polarizing responses. B-cell receptor (BCR) engagement provided the main signal for interleukin (IL)-12Rb1 expression in the two subsets: this was potentiated by CD154 together with interferon-gamma (IFN-gamma) but inhibited by IL-12. IL-12Rb2 could be induced on a minority of B cells by the same signals, and also by IFN-gamma alone. WSX-1, a receptor for IL-27, was expressed in both subsets with no evidence for its regulation by the signals studied. While neither subset was capable of secreting much IL-12 p70, memory B cells could produce a small amount of IL-12 p40 on CD40 ligation. Memory B cells also, exclusively, expressed IL-23 p19 mRNA on BCR triggering. Importantly, products of appropriately stimulated memory – but not naive – B cells were shown to promote the synthesis of IFN-gamma in uncommitted T-helper cells. The data indicate an equal capacity for naive and memory B cells to respond within a type 1 polarizing environment. Although poorly equipped for initiating type 1 responses, B cells – by virtue of the memory subset – reveal a capacity for their maintenance and amplification following T-dependent signalling.

IL-12; IL-23; IL-27; B cells; immune polarization

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