# Snodgrassella alvi as an attenuated live vaccine against Neisseria gonorrhoeae

> **NIH NIH R21** · UNIVERSITY OF FLORIDA · 2020 · $190,625

## Abstract

ABSTRACT
New cases of gonorrhea are approximately 80 and 1 million worldwide and in the US, respectively.
Since no vaccine against Neisseria gonorrhoeae exists, the quest for a gonococcal vaccine was
hotly pursued, but the poor outcomes from clinical trials and the ease of antibiotic treatment
subdued further vaccine research. Currently, N. gonorrhoeae is developing antibiotic resistance
at a pace that is projected to make them untreatable in the near future. The recent finding that the
vaccine against Group B Neisseria meningitidis, MeNZB, confers partial protection against
gonorrhea, suggests that a gonococcal vaccine is feasible. Given this finding, we hypothesize that
Snodgrassella alvi, which branches within the family Neisseriaceae, and is a related genus to
Neisseria, Kingella, and Eikenella, can be deployed as a naturally attenuated, nonpathogenic live
vector vaccine for N. gonorrhoeae. S. alvi is not expected to colonize humans because it is severely
niche-restricted to the specific bees it colonizes. Moreover, our in silico analysis shows that S. alvi
virtually lack all major virulence factors of pathogenic Neisseriaceae, including a dedicated
machinery to retrieve iron from the host. Preliminary data support our hypothesis in that 1) S. alvi
is safe in mice when administered intraperitoneally at high doses; 2) S. alvi induces high IgG titers
that cross-react to N. gonorrhoeae; and 3) IgG titers translate into robust bactericidal activity. The
proposed research will expand these initial observations to ascertain S. alvi as a gonococcal
vaccine. Studies in Aim 1 will optimize parenteral and mucosal routes of vaccination to stimulate
elevated neutralizing antibodies and effector T cells indicative of cell-mediated immunity. Studies
will assess if adjuvants are required, and whether a mucosal prime, parenteral boost best
stimulates protective immunity. Studies in Aim 2 will assess S. alvi `s efficacy against vaginal N.
gonorrhoeae challenge.

## Key facts

- **NIH application ID:** 9955471
- **Project number:** 1R21AI151424-01
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **Principal Investigator:** Massimo Maddaloni
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $190,625
- **Award type:** 1
- **Project period:** 2020-09-16 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9955471

## Citation

> US National Institutes of Health, RePORTER application 9955471, Snodgrassella alvi as an attenuated live vaccine against Neisseria gonorrhoeae (1R21AI151424-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9955471. Licensed CC0.

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