| PrincessKiara70 2004-12-21, 4:07 am |
| http://www.news-medical.net/?id=6871
Key advance in understanding the proteins and mechanisms involved in
the spread of Lyme Disease
Posted By: News-Medical in Disease/Infection News
[ editor@news-medical.net ]
Published: Thursday, 16-Dec-2004
Virginia Commonwealth university scientists have made a key
advance in understanding the proteins and mechanisms involved in the spread
of Lyme Disease, a finding that could lead to a vaccine against the
tick-borne illness that affects thousands of people each year.
In the December issue of the Journal of Immunology, the
researchers characterized the molecular interaction that occurs between an
important virulence factor in Lyme disease spirochetes, known as OspE, and a
host protein, factor H (fH), which is an important regulator of the immune
system. It is the binding of fH by the Lyme disease pathogens that allows
the bacteria to avoid being destroyed by the host, according to the article.
Defining the nature of the interaction between fH binding proteins and fH
may facilitate the development of a new generation of vaccines against the
bacteria.
"Understanding the complex interaction between the different
residues and structural elements of these key proteins involved in the
pathogenesis of Lyme Disease is a significant step forward in our research,"
said Richard T. Marconi, Ph.D., associate professor of microbiology and
immunology at VCU.
Lyme disease spirochetes use fH-binding as a virulence
mechanism - an ability that has also been observed in several other
dangerous pathogens, including those responsible for HIV; various species of
Neisseria, which cause diseases like meningitis and gonorrhea; and some
types of parasites.
"In addition, what we have learned in our study of fH binding by
the Lyme disease bacteria can be applied to vaccine development for other
organisms that bind fH as well," he said.
Leading one of the largest Lyme Disease research efforts in the
country, Marconi's lab demonstrated that fH-binding by OspE was dependent on
the formation of specific structural elements. Disruption of these
structural elements resulted in the loss of the fH-binding capability.
"For example, the use of modified forms of OspE that can not
bind fH as a vaccinogen may elicit an immune response that will prevent the
pathogen from binding fH and thus the bacteria will no longer be able to
persist in an infected individual," he said. "The modification of fH binding
proteins may allow for the development of a novel class of proteins that can
be used in the development of a Lyme disease vaccine."
Studies are currently under way to determine if these modified
proteins will offer improved protection against Lyme Disease.
Lyme disease is extremely difficult to diagnose and no reliable
test or vaccine is currently available. It is transmitted by the bite of an
infected Ixodes tick. Ticks are able to survive under a variety of
conditions as long as adequate moisture is available. In the United States,
the peak season for ticks is April to September in the northeast, and from
November to April in the west.
Marconi's research is supported by three grants from the
National Institutes of Health, totaling about $4 million. He collaborated
with John McDowell, Ph.D., a postdoctoral fellow in the VCU's Department of
Microbiology and Immunology.
http://www.vcu.edu
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