# Presentation: 521075

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## Laboratory of Enteric and Sexually Transmitted Diseases Historical Perspective

_**Origin**_**: Began in 1994 - Established to review the rapidly increasing number of enteric disease products and expected STD products.**
_**Mission:**_
**	****a. Conduct basic/applied research **
**molecular bases of pathogenesis**
**host’s immune responses to infection**
**develop models to measure vaccine safety, immunogenicity and efficacy**
**	****b. Utilize knowledge base**
**enhance product manufacturing analyses**
**better assess product safety and efficacy**
_**Program Review:**_
**	****	**_**Last scientific program site-visit review - Aug. 2002**_
**	**

## Laboratory of Enteric and Sexually Transmitted Diseases   Regulatory Responsibilities

**Responsible for review of IND’s and BLA’s for bacterial enteric, UTI and STD products and certain other assigned products.**
**LESTD is responsible for covering products related to intestinal disease agents (e.g. *****Shigella*****, *****Salmonella***** spp., all pathogenic *****Escherichia coli’s, Campylobacter, Vibrio cholerae, Helicobacter pylori, hookworm*****), the use of live attenuated enteric bacteria as vaccine vectors or as anti-cancer therapy, UTI pathogens, probiotic/LBP therapy (e.g. Tx cancers, IBD, CF), L-aspariginase, bacteriophages or bovine/chicken immunoglobulin concentrates for therapeutic use, and genetic hybrid plant vaccines. [ Involves oral, parenteral, intrarectal, intravaginal, intranasal, transcutaneous routes + new adjuvants].**
_**Annual workload**_** -**
**	****	****New candidate products =  >1/month**
**	****	****Review time commitment:**
**	****	****	****	****Stibitz and Kopecko - ~50% review effort**
**	****	****	****	****Carr and Osorio -  25-30% review effort**
**	****	****	****	****Bhattacharyya - ~ 80% review effort**

## Laboratory of Enteric and Sexually Transmitted Diseases Personnel and Budget - (2003-2006)

_**Personnel**_** -**
**	****	**_**Molec. Pathogenesis Gp.**_** - increased from 2 to 7**
**	****	**_**Gene Regulation Gp.**_** - declined from 5 to 3**
**	****	**_**STD Gp.**_** - inactivated due to lack of STD vaccine activity and ****	****	****	****departure of C. Deal.**
**	****	**_**Immune Mechanisms Gp.**_** - created in 2002, new research ****	****	****	****initiatives being developed**
_**Budget**_** ****- FDA intramural research budget continued its decrease.**
**Fortunately, outside grant support replaced the intramural budget decline. **
**Problem: lack of internal funding consistency, outside grantors limited in number (e.g. special NIH funding).**
**	****	**

_**Public Health Issue**_**:**** **
**Enteric bacterial diseases cause ~350 million US episodes of diarrhea/yr**
**kill more than 2 million children worldwide annually**
**Limited data on pathogenesis and immune responses has slowed the development of enteric vaccine products**
_**Research Relevance to DHHS and FDA Priorities:**_**LESTD research programs are entitled: **
**“ ****Enteric Bacterial Pathogens – Improving Safety and Efficacy of Combination Vaccines for Diarrheal Diseases and Select Agents”**
**“****Bacterial Vaccine Safety: Biomarkers of Virulence and Attenuation in *****Bordetella pertussis***** (Whooping Cough) and Anthrax Bacteria.”**

**Laboratory of Enteric and Sexually Transmitted Diseases**** **_**Relevance of Research Program To CBER’s Public Health Mission**_

## Laboratory of Enteric and Sexually Transmitted DiseasesResearch Programs - 1

_**Molecular Pathogenesis Section**_** -**
**Studies of *****Salmonella***** Typhi Ty21a as a safe vector for expression of foreign antigens**
**Pathogenesis and immune responses to *****Campylobacter jejuni***** infection in humans**
**Minor research projects - aided by key collaborations.**
**	**

## I. Studies of Salmonella Typhi Ty21a as a safe vector for expression of foreign antigens

_**Key Goals**_
**Define key attenuating features of Ty21a**
**   ****(Genomic sequence and microarray analyses)**
**Optimizing a temperature-stabilized formulation and delivery system**
**	****(NIAID-supported collaboration with Aridis Pharmaceuticals LLD)**
**Demonstrate stable expression of targeted *****Shigella *****or anthrax genes in a live platform vector system**

## 2. Pathogenesis and immune responses to Campylobacter jejuni infection in humans 

- _Overall goals of project_:
**Examine *****C. jejuni***** attachment, invasion, and exocytosis events by TEM and SEM.**
**Define host signal transduction pathways involved in *****C. jejuni***** internalization into epithelial cells**
**Study *****C. jejuni***** interaction with human DCs for cytokine/chemokine responses involved in inflammation**

## Laboratory of Enteric and Sexually Transmitted DiseasesResearch Programs - 2

_**Immune Mechanisms Section**_
- 	_***New Directions***_** – Evaluate approaches to achieving mucosal immunization**

## Immune Mechanisms Section

***Mucosal Immunization against Enteric Pathogens***

**Study methods useful for inactivation of enteric bacteria**
**Demonstrate immunogenicity of antigen delivery systems**
**Transcutaneous immunization**
**Bacterial ghosts**
**Mucosally delivered whole cells**
**Develop Animal Models for Evaluating Vaccine Efficacy Against Enteric Pathogens**

## Laboratory of Enteric and Sexually Transmitted DiseasesResearch Programs - 3

_**Gene Regulation Section**_** -**
**	****I. Virulence Gene Regulation - using *****B. pertussis***** as model system.**
**	****II. Development of Genetic Tools for the Analysis and Manipulation of *****Bacillus anthracis*****.****	**

## I. Virulence Gene Regulation - using B. pertussis 

**	****	****	****as model system**
**	**
**	****	****A.  Molecular mechanisms of virulence gene activation**
**	****	****by the BvgAS two-component system**
_**Progress**_**:  Completed a study of eight different BvgA-**
**regulated virulence gene promoters for high-resolution mapping**
**of BvgA-binding sites using BvgA conjugated to Fe-BABE.**
_**Future Directions**_**:  More detailed studies of specific promoters **
**and comprehensive genetic studies to elucidate critical **
**interactions of BvgA with RNA polymerase.**

## I. Virulence Gene Regulation - using B. pertussis 

**	****	****	****as model system**
- 		**B. Development of Genetic Tools**
**	**
_**Progress:**_**  Have constructed a powerful allelic exchange system**
**for manipulation of unmarked *****B. pertussis***** strains (for use**
**in animal studies)**

## I. Virulence Gene Regulation - using B. pertussis 

**	****	****	****as model system**
**Use of bioluminescence to characterize *****B. pertussis***** infection**
**in a mouse aerosol challenge model.**
_**Progress:**_**  Have demonstrated utility of *****in vivo***** imaging system for **
**examining pertussis infection - can follow individual mice over time.**
**Characteristic growth in upper respiratory (nose) tract followed by**
**growth in lungs and trachea.**
_**Future Directions:**_**  Implementation to characterize the effect**
**of mutations that affect key/novel virulence genes and regulatory **
**phenotypes.**

## 2.  Development of Genetic Tools for the Analysis and 		   Manipulation of Bacillus anthracis

**Developed routine allelic-exchange procedures**
**Constructed over 70 directed mutants of *****B. anthracis*****.**
_**Future Directions:**_** **
**Development of additional tools:  expression vectors, promoter assay vectors, transposon delivery vectors.**
**Application of tools in a genomic search for new virulence genes (****funded by MARCE developmental grant****)**
**Characterization of underlying causes for sub-optimal stability of rPA anthrax vaccine **
**	****(funded by CBER/NIAID partnership)**