# BORDETELLA CYCLASE: STRUCTURE AND BIOLOGICAL ACTIVITY

> **NIH NIH R01** · UNIVERSITY OF VIRGINIA · 1989 · $204,817

## Abstract

Pertussis (whooping cough) is a major childhood illnesses in the
developing world and, as a result of concerns about pertussis
vaccine reactogenicity, has increased in incidence in many areas
of the developed world.  In the development of a non-whole cell
pertussis vaccine, several important toxins and virulence factors
are being considered as potential vaccine antigens.  A major
candidate among these is the adenylate cyclase (AC) toxin, which
is the focus of this research project.

Bordetella pertussis AC toxin is a calmodulin-activated enzyme
which is novel in its location external to the cytoplasmic
membrane of the bacterium and its ability to bind to and enter
target eukaryotic cells where it catalyzes the production of cAMP
from endogenous ATP.  In this laboratory the enzyme/toxin has
been partially purified to extremely high enzymatic specific
activity while retaining its toxin activity, and monoclonal
antibodies have been prepared.  In the work proposed herein, the
monoclonal antibodies will be characterized further and used to
immunopurify the AC toxin.  The toxin subunit structure will be
evaluated with the use of the monoclonal antibodies and other
techniques.  The AC toxin gene will be identified and sequenced
and the isolated gene employed to obtain in vitro expression of
the protein.  A major focus of the work will be investigation of
the delivery, binding and cell entry mechanisms for the toxin.
Immuno-electron microscopy will enable study of these processes
and determination of the intracellular fate of the toxin.

In line with the development of a new pertussis vaccine, the
purified AC toxin (or toxoid thereof) and antibodies directed
against the toxin will be tested for their ability to protect against
infection with B. pertussis in the mouse intracerebral challenge
and the mouse aerosol infection model.  Sera from patients
convalescent after pertussis will be examined for antitoxin
activity.  Finally, B. pertussis AC toxin will be compared and
contrasted with the only other known AC toxin, from Bacillus
anthracis.  The homology of DNA sequence, immunologic cross
reactivity, relationships between receptors and entry mechanisms
will be examined, enabling consideration of the evolutionary
development and relatedness of the two.

The work proposed in this application and ongoing at present will
provide information of use in vaccine development and of
importance to the understanding of bacterial toxins and their
roles in pathogenesis of bacterial disease.

## Key facts

- **NIH application ID:** 3127626
- **Project number:** 5R01AI018000-08
- **Recipient organization:** UNIVERSITY OF VIRGINIA
- **SAM.gov UEI:** JJG6HU8PA4S5
- **Principal Investigator:** ERIK L HEWLETT
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $204,817
- **Award type:** 5
- **Project period:** 1980-09-01 → 1991-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3127626

## Citation

> US National Institutes of Health, RePORTER application 3127626, BORDETELLA CYCLASE: STRUCTURE AND BIOLOGICAL ACTIVITY (5R01AI018000-08). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3127626. Licensed CC0.

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