Vaccination with a commensal from honey bees confers protection against vaginal Neisseria gonorrhoeae (Ng) challenge 3080

Abstract Description Ng is acquiring increased resistance to antibiotics that is outpacing new antibiotic development. Treatment of gonorrhea remains problematic given that new annual cases approximate 82 million worldwide and 1.6 million in the US. Natural immunity to gonorrhea is ineffective. Thus, an efficacious gonococcal vaccine is much needed. The vaccine against Group B Neisseria meningitidis, 4CMenB, can confer partial cross-protection against gonorrhea, suggesting that a gonococcal vaccine is feasible. In light of this finding, we hypothesize that Snodgrassella alvi, which branches within the family Neisseriaceae, can be deployed as a naturally attenuated, nonpathogenic live vector vaccine for Ng. S. alvi is not expected to colonize humans due to its niche-restriction to bees. In silico analysis found that S. alvi lacks virtually all major virulence factors associated with pathogenic Neisseriaceae, including a dedicated machinery to retrieve iron from the host. To test our hypothesis, groups of mice were vaccinated by the intraperitoneal (IP) route three times, and elicited high serum and vaginal IgG antibody (Ab) titers that cross-react to Ng. Serum IgG Abs were robustly bactericidal. When groups of IP-vaccinated BALB/c females were subjected to vaginal Ng challenge, only 13% of S. alvi-vaccinated mice showed Ng colonization post-1 wk challenge compared to 76% unvaccinated controls. Thus, S. alvi confers exquisite protection against vaginal Ng challenge. Funding Sources Work supported by NIH AI151424. Topic Categories Mucosal and Regional Immunology (MUC)