A discovery of how the body’s immune system
protects against malaria may hold promise for a vaccine against the disease,
which kills as many as 600,000 people each year, mostly children. Currently, no
effective vaccine exists for the mosquito-borne disease, which infects the
bloodstream and red blood cells, leading to fatigue, headaches, and in severe
cases, death.
Antibodies play major roles in immunity to malaria,
but a limited understanding of mechanisms mediating protection long has been a
barrier to vaccine development. Researchers have known antibodies alone were
mostly ineffective at targeting the malaria organism, leading them to believe
the antibodies in people resistant to malaria must be getting help from other
parts of the immune system.
Professor
James Beeson, who heads Burnet’s Centre for Biomedical Research in Melbourne,
Australia, said he and his research team discovered that antibodies “needed to
recruit other proteins in the blood” in order to block malaria infection. This
mechanism, known as a complement,” helps the antibodies coat the malaria
organism, according to Beeson. “By working together,” he adds, “these two
things are a double-hit that stops malaria from infecting red blood cells.”
The
findings represent a major advance in understanding immunity to malaria and
provide a much-needed strategy for the development and evaluation of vaccines.
Beeson says Burnet’s researchers will now apply
this new knowledge to their strategies to create new and more effective malaria vaccines.
“Exploiting this malaria-blocking activity is a new
approach in developing a vaccine. We have shown that it is possible to
effectively generate this protective immune response by immunizing humans with
a candidate vaccine,” Beeson says.
Historically, vaccines were developed to protect
against bacterial and viral diseases that plagued the world population through
the 1950s and 1960s. Diphtheria, tetanus, pertussis, polio, smallpox and
malaria, among others, were produced in mass quantities to treat large
populations.
The advances in immunology, biochemistry,
microbiology and biotechnology during the past four decades have opened up the
possibilities of creating vaccines for a variety of diseases, including
Alzheimer’s, certain cancers, HIV, multiple sclerosis, various tropical
diseases, and autoimmune disorders such as diabetes, lupus erythematosus and
arthritis.
Vaccines are also being developed against new
targets, including Japanese encephalitis, meningitis, certain pollen allergies,
metastatic melanoma, Type I diabetes, oral rotavirus, hypertension, and
enterotoxigenic Escherichia coli infection.
Currently, researchers are conducting more than 640
clinical trials around the world on a wide variety of vaccines. The World
Health Organization estimates there are 120 new vaccines in
pharmaceutical/biopharmaceutical company pipelines.
In the United States, the FDA will approve a
vaccine if there exist an adequate immunological response, patient safety and
established effectiveness of the vaccine at controlling the disease. Vaccine
development, approval and production are a costly and long-term venture for any
pharmaceutical company. It demands separate, dedicated facilities, equipment
and staff. This requires that there be potential revenue and large, diverse
patient populations to allow a company to enter into a vaccine venture.
For our BCC
Research report on vaccines, visit the following link:
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