# Designer probiotics for prevention of cholera

> **NIH NIH R21** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $210,000

## Abstract

PROJECT SUMMARY
Cholera, an acute diarrheal illness, causes 3-5 million cases and over 100,000 deaths worldwide each year,
particularly in resource poor settings. Areas of humanitarian crises are often associated with cholera outbreaks
due a breakdown in access to clean water. The mainstay of cholera treatment is oral rehydration, a potentially
life-saving intervention, while the best long-term prevention strategy is to improve access to clean water and
improved sanitation, infrastructure modifications that can take years to implement. To slow the spread of
cholera, particularly in the setting of emerging outbreaks, in 2013 the WHO began stockpiling oral killed
vaccines for use in reactive vaccination campaigns. This strategy is demonstrating efficacy; however, one of its
limitations is that post-vaccination, it takes 2 weeks to develop protective immunity. Thus, interventions that
provide protection during this window are needed. Here, as a stopgap measure to address this issue, we
propose to develop designer variants of the probiotic Escherichia coli Nissle 1917 (EcN) that we have
equipped with a protein delivery system (T3EcN) to secrete relevant therapeutics into the gastrointestinal
lumen of at risk individuals. Interestingly, prior infection with cholera provides protection for ~5 years and
humans infected with cholera have been found to primarily generate antibodies that target and block the
activity of the two cholera toxin subunits (CTA and CTB), sialidase and the O-specific polysaccharide (OSP)
moiety of its LPS. These observations strongly suggest that probiotic-mediated deposition of agents that block
the activity of these virulence factors, i.e., single domain antibodies (aka VHH), should also act to prevent the
development of cholera. Here, in Aim 1, we propose to identify and develop heterodimers of VHH that
neutralize OSP, CTB and Sia. These heterodimers will be engineered to be recognized as secreted proteins by
T3EcN, a variant of EcN that encodes a modified type III secretion system, which secretes proteins into its
surrounding rather than into host cells. In Aim 2, using the well-established mouse neonatal cholera model, we
will investigate the ability of T3EcN that secrete these VHH to block the development of cholera as well as the
deposition of cholera into intestinal epithelial cells. These exploratory studies have the potential to lead to the
development of a new low-cost intervention to stem the spread of emerging cholera epidemics.

## Key facts

- **NIH application ID:** 9896226
- **Project number:** 1R21AI144716-01A1
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** CAMMIE LESSER
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $210,000
- **Award type:** 1
- **Project period:** 2020-02-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9896226

## Citation

> US National Institutes of Health, RePORTER application 9896226, Designer probiotics for prevention of cholera (1R21AI144716-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9896226. Licensed CC0.

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