摘要：SummaryNeutrophils played a key role in the innate immune responses. Less is known about whether and how the neutrophils recruited in the immunization sites affecting the vaccine-induced antibody responses. In the process of evaluating the efficacy of an oil-in-water emulsion-formulated vaccine in mice, we found that neutrophils were rapidly and massively recruited to immunization sites but were barely detected in the draining lymph nodes. Interestingly, B cell-activating factor (BAFF) was abundantly expressed in the recruiting neutrophils at a very early stage. The initial neutrophil-derived BAFF firstly brought about the B cell responses in the local part, then subsequently in lymphoid organs. Activated B cells produced more BAFF through TLR9-IRF5 signaling pathway, thereby amplifying the vaccine-induced antibody responses. Suppressing BAFF in the neutrophils could weaken the B cell activation and reduce the antibody production. The data indicate that vaccines endow neutrophils with the potential to orchestrate antibody responses at immunization sites.Graphical abstractDisplay OmittedHighlights•Neutrophils at immunization sites influencing subsequent immune responses•Neutrophil-driven BAFF at immunization sites assisting B cell responses to vaccines•Activated B cells produce more BAFF through TLR9-IRF5 signaling pathway•BAFF-producing neutrophils orchestrate antibody responses at immunization sitesComponents of the immune system; Immune response; Immunology
