By Doris Ryan, Naval Medical Research Center Public Affairs
SILVER SPRING, Md. (NNS) -- A vaccine to protect against
Campylobacter jejuni was recently approved for human clinical trials by the
Food and Drug Administration.
Researchers at the Naval Medical Research Center (NMRC)
began an FDA approved phase 1 clinical trial for a C. jejuni vaccine at the
Walter Reed Army Research Institute Clinical Trials Center in April. C. jejuni
is a global health problem and is a leading cause of diarrhea in deployed
military personnel and international travelers.
Dr. Patricia Guerry, a senior scientist at NMRC, was one of
the first molecular microbiologists to address the health concerns of
Campylobacter in the 1980s, a decade after it was first discovered and
recognized as a cause of human diseases. Teaming up with Dr. Mario Monteiro,
from the University of Guelph in Ontario, Canada, Guerry oversaw the design and
development of a prototype C. jejuni vaccine.
"Work on conjugate vaccines against C. jejuni started
in 2004 and the initial studies were done in parallel with other vaccine
approaches," said Guerry. "These initial promising studies
demonstrated immunogenicity in mice. A prototype vaccine is being used in this
clinical trial with the primary aim of evaluating the safety of this vaccine
and immune responses."
This phase 1 study will enroll up to 48 healthy volunteers
to determine safety and dosing levels. Cmdr. Robert Gormley is leading the
study.
"We are vaccinating up to 48 volunteers with an
injection to the upper arm," Gormley said. "Since this is a dose
escalation study, we are vaccinating sixteen volunteers with a low dose before
subsequently vaccinating an additional two groups of sixteen each at higher
doses. It is hoped that at the end of the study, the results will allow the
research team to take the vaccine into a phase 2 study where volunteers will be
vaccinated to see if it protects against Campylobacter in a human challenge
study."
He added that the emerging epidemiology and understanding of
campylobacter-attributed burden in military personnel, travelers and global
populations combined with the promising development of the Campylobacter
vaccine may lead to wider interest in the development of a vaccine against this
disease.
Diarrhea has historically been a substantial cause of
morbidity for deployed U.S. military personnel and continues to the present
day.
The NMRC Enteric Diseases Department's research program is centered
on the development of effective countermeasures to prevent or abate bacterial
diarrhea, with most efforts aimed at vaccine research and development. NMRC
researchers have identified many surface structures of the bacteria, found how
it invades human cells, and characterized many aspects of the immune response.
This work continues with the use of comparative genomics, expression arrays,
and studies to try to better understand the protective immune response, all of
which will enable researchers to develop an effective vaccine.