The cellular immune response elicited by TTFC and spore-adsorbed TTFC treated with probiotic. sensible request. Abstract Background Spore-forming bacteria of the genus are widely used probiotics known to exert PC786 their beneficial effects also through the activation of the sponsor immune response. The oral delivery of spores offers Rabbit Polyclonal to EPN1 been shown to improve the immune response to a parenterally given viral antigen in mice, suggesting that probiotics may increase the effectiveness of systemic vaccines. We used the C fragment of the tetanus toxin (TTFC) like a model PC786 antigen to evaluate whether a treatment with spores affected the immune response to a mucosal antigen. Results Purified TTFC was given to mice from the nose route either as a free protein or adsorbed to spores, a mucosal vaccine delivery system proved effective with several antigens, including TTFC. Spore adsorption was extremely efficient and TTFC was shown to be revealed within the spore surface. Spore-adsorbed TTFC was more efficient than the free antigen in inducing an immune response and the probiotic treatment improved the response, increasing the production of TTFC-specific secretory immunoglobin A (sIgA) and causing a faster production of serum IgG. The analysis of the induced cytokines indicated that also the cellular immune response was improved from the probiotic treatment. A 16S RNA-based analysis of the gut microbial composition did not display dramatic differences due to the probiotic treatment. However, the large quantity of members of the 6 genus was found to correlate with the improved immune response of animals immunized with the spore-adsorbed antigen and treated with the probiotic. Summary Our results indicate that spores significantly contribute to the humoral and cellular responses elicited by a mucosal immunization with spore-adsorbed TTFC, pointing to the probiotic treatment as an alternative to the use of adjuvants for mucosal vaccinations. were shown able to increase the immune response to a parenteral vaccine against bovine herpesvirus type 5 (BoHV-5) in mice [13]. originally defined as var. toyoi and then recognized as a new varieties by genomic analysis [14], was used in animal nourishment for swine, poultry, cattle, rabbits and aquaculture. In 1994 PC786 its use has been authorized by the Western Community like a feed additive for use in poultry, cattle and rabbits [15]. Animals parenterally immunized with BoHV-5 and orally supplemented with spores experienced higher serum IgG, IL-4 and IL-12 levels than immunized animals that did not receive the probiotic [13], suggesting this probiotic treatment like a potential alternative to the use of adjuvants. The aim of this work was to investigate whether the oral treatment with spores of was also effective in inducing the production of specific sIgA thus improving the immune response induced by a mucosal antigen. The C fragment of the tetanus toxin (TTFC), the protecting antigen used in evaluations of vaccines against tetanus, was selected like a model antigen [16]. TTFC given by the oral or nose route was shown to induce a protecting immune response in mice when delivered by spores either like a fusion protein revealed within the spore surface [17C19] or like a genuine protein adsorbed within the spore surface [20]. The use of spores like a mucosal delivery system has been exploited in recent years and tested with several antigens and enzymes [6, 21, 22]. In addition to.