Distinct modes of action of CD40L and adaptive cytokines IL-2, IL-4/13, IL-10 and IL-21 on rainbow trout IgM+ B cells. (October 2020)

• Record Type: Journal Article
• Authors: Abos, Beatriz; Wang, Tiehui; Secombes, Christopher J.; Tafalla, Carolina
• Is Part Of: Developmental and comparative immunology. Volume 111(2020)
• Publication Date: 2020-10
• Subjects: B cells -- CD40L -- IL-2B -- IL-4/13 -- IL-10 -- IL-21; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2020.103752
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: In mammals, conventional B (B2) cells are activated within lymphoid follicles through a close relationship with T follicular helper (Tfh) cells. The interaction between CD40 expressed on B cells and its ligand (CD40L) expressed on Tfh cells is a key signal that regulates the formation of germinal centers (GCs), B cell survival, proliferation and differentiation to plasma cells (PCs) or memory cells. Additionally, certain soluble cytokines produced by T cells also strongly condition the outcome of this interaction. Despite the many differences found between fish B cells and mammalian B2 cells, and the lack of conventional GCs, rainbow trout IgM + B cells have been shown to be stimulated by CD40L, however, whether cytokines commonly produced by T cells can further modulate this response has never been addressed to date. Thus, in this study, we determined the effects of recombinant rainbow trout adaptive cytokines interleukin 2B (IL-2B), IL-4/13A, IL-4/13B, IL-10 and IL-21 (cytokines known to activate B cells in mammals) on splenic IgM + B cells alone or in combination with CD40L. We studied how these cytokines and CD40L cooperated to promote IgM + B cell survival, proliferation and IgM secretion. The results obtained provide valuable information for the first time in teleost fish on how different T cell signals cooperate to activate B cells in the absence of GCs. Highlights: IL-2B, IL-10 and IL-21 increase the survival of rainbow trout IgM + B cells. IL-2B and IL-21 induced the proliferation of rainbow trout IgM + B cells. All cytokines up-regulated the number of IgM-secreting cells in splenocyte cultures. IL-10 and IL-21 cooperated with CD40L to promote IgM + B cell survival, proliferation and IgM-secretion. IL-2 cooperated with CD40L to up-regulate IgM + B cell survival and proliferation but not IgM secretion.