The Hierarchical Process of Differentiation of Long-Lived Antibody-Secreting Cells Is Dependent on Integrated Signals Derived from Antigen and IL-17A

Abstract

Switched CD19-positive memory B cells purified from mice with chronic immune response against Thalassophryne nattereri venom proteins were cultured with venom or cytokines. Our results confirm the existence of a hierarchic process of differentiation: activated memory B cells progressively acquire increasing levels of CD138 and decreasing levels of CD45R/B220 to finally arrive at ASC with B220neg phenotype, which are IgG1-secreting cells. Only Bmem from peritoneal cavity or bone marrow of VTn immunized mice presented the capacity to generate ASC functionally active. IL-17A or IL-21/IL-23/IL-33 improves the ability of venom to induce intracellular IgG of peritoneal derived-ASC. Cognate stimulation with venom and IL-17A is sufficient to down-regulate the expression of CD45R/B220. BAFF-R is up-regulated in splenic or medullar derived-ASC stimulated by venom, CpG or cytokines. Only splenic derived-ASC up-regulate Bcl-2 expression after CpG or the combination of IL-21/IL-23/IL-33 stimulation. Finally, the activation of ASC for IgG1 secretion is triggered by venom proteins in peritoneal cavity and by IL-17A in medullar niche. These results show the importance of the integration of signals downstream of BCR and IL17-A receptors in modulating ASC differentiation, focusing in the microenvironment niche of their generation.

Thalassophryne nattereri fish venom: from the envenoming to the understanding of the immune system

“…Then, we confirmed in an in vitro model the existence of a hierarchical process in which CD19-positive Bmem become CD138-positive IgG producing-ASC by a mechanism directly dependent on B-cell receptor (BCR) stimulation by venom, which could be potentiated by IL-17A [30]. Collectively, these studies shed new light on survival factors involved in the differentiation and maintenance of ASC in inflamed tissue and demonstrated that these cells require signals derived from antigen and IL-17A for the secretion of venom-specific antibodies for long periods of time.…”

Bioactive Components in Fish Venoms

“…Long-term immune protection requires the persistence of vaccine antibodies and/or the generation of immune memory cells capable of rapid and effective re-activation upon subsequent exposure. Data from work on T. nattereri venom in mice strongly implies that IL-17A derived from effector memory T-cells govern the differentiation of germinal center derived-memory-B cells into antibody-secreting cells and maintain their longevity through a mechanism directly dependent on B-cell receptors, and T. nattereri venom was found to affect these processes [ 123 , 124 , 125 ]. Additionally, it was found that the proteolytic activity of a novel toxin family from T. nattereri venom, known as Natterins, is critical for the hierarchical differentiation of antibody-secreting cells, and for the adjuvanticity of the venom [ 126 , 127 ].…”

Toll‐like receptor 4 signalling regulates antibody response to adenoviral vector‐based vaccines by imprinting germinal centre quality

“…This may indicate that the participation of TLR4 in GC responses alters the nature of output from GC B cells to LLPCs as the response progresses. We examined the IL‐17A secretion in serum after immunization, because IL‐17A can assist with the survival of LLPCs . However, we did not observe a significant difference between immunized WT and TLR4‐KO mice.…”

“…In fact, several factors contribute to the survival of LLPCs, such as IL‐17A . To test whether the level of IL‐17A was affected by the TLR4 deficiency, we measured the secretion of IL‐17A using flow cytometry.…”