# VIRULENCE FACTORS IN THE PATHOGENESIS OF SALMONELLOSIS

> **NIH NIH R01** · UNIVERSITY OF TEXAS MED BR GALVESTON · 1988 · $178,213

## Abstract

The pathogenesis of salmonellosis appears to involve a combination
of virulence factors that contribute to either gastroenteritis or
enteric fever.  The initial intestinal phase of the infection
includes both invasion of epithelial cells and elaboration of
protein toxins.  This research program will continue to define the
virulence mechanisms that contribute to the diarrheal phase of this
disease and to identify those factors allowing progression of the
infection to the more severe septicemic form.  The major advances
in the study of this disease during the current project period have
been the purification and characterization of a cholera toxin-
related enterotoxin from Salmonella, made possible by our recent
success in cloning the chromosomally encoded enterotoxin (stx) gene
of Salmonella.  A multi-directional approach has been designed to
1) sequence the cloned stx gene, 2) prepare isogenic (stx-) mutants
of Salmonella, 3) evaluate the virulence of the Salmonella mutants,
4) Purify and characterize the cloned Salmonella enterotoxin from
fermenter cultures of Escherichia coli (pCHP4) (expressing the
enterotoxin) and compare with native Salmonella enterotoxin
isolated by specific antibody affinity chromatography, 5) perform
automated amino acid sequence analysis of the purified enterotoxin
to confirm the nucleotide sequence, and 6) compare the purified
enterotoxin with cholera toxin and E. coli LTI, using antigenic,
biologic, and chemical methodologies.  Additionally, sera and
intestinal washings from salmonellosis patients will be assayed
with a Salmonella enterotoxin-specific ELISA, as well as by toxin
neutralization in rabbit skin and intestinal loops, to determine
if these patients develop a rising antitoxin titer following
infection.  In addition, we will continue research efforts to
clarify the role of a less-defined cytotoxin in the pathogenesis
of salmonellosis.  The purification scheme for the Salmonella
cytotoxin will be refined further, and the purified cytotoxin will
be tested for effects on the intestinal mucosa of adult rabbits by
light and electron microscopy.  Further studies will also be
pursued to study the importance of the divalent cation, Ca , in
enhancing the invasion of Salmonella in orally challenged mice
leading to an increased rate of death.  Search for Ca mediated
alterations in cell envelope proteins that could account for the
enhanced invasive capacity of Ca++-grown cells will continue.  This
program of research should continue to provide new information
about the pathogenesis of salmonellosis.

## Key facts

- **NIH application ID:** 3127907
- **Project number:** 2R01AI018401-07
- **Recipient organization:** UNIVERSITY OF TEXAS MED BR GALVESTON
- **SAM.gov UEI:** MSPWVMXXMN76
- **Principal Investigator:** JOHNNY Wayne PETERSON
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1988
- **Award amount:** $178,213
- **Award type:** 2
- **Project period:** 1982-09-01 → 1993-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3127907

## Citation

> US National Institutes of Health, RePORTER application 3127907, VIRULENCE FACTORS IN THE PATHOGENESIS OF SALMONELLOSIS (2R01AI018401-07). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3127907. Licensed CC0.

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