d the first component of the vaccine strategy, a circular piece of DNA designed to carry genes for both SIV and HIV proteins. When this DNA is injected into monkeys, an immune response against SHIV is triggered. The scientists then boosted the immune response with a second vaccine, developed by NIAID's Bernard Moss, M.D., Ph.D., and his colleagues. To construct the second vaccine, the researchers added the same genes to a virus called MVA. This virus, a modified version of vaccinia virus that cannot reproduce in human cells, was first produced in the 1960s as a safe, effective smallpox vaccine. Later research led by Dr. Moss, who is chief of NIAID's Laboratory of Viral Diseases, further developed the virus for use as a vehicle to ferry genes into the body.
Both vaccines lack certain HIV genes to ensure against formation of HIV itself, so there is no chance of HIV infection due to vaccination. "Our results show that we can protect monkeys against an HIV-like virus using an immunization scheme that is practical for use in people," explains study director Harriet Robinson, Ph.D., chief of the division of microbiology and immunology at Emory University's Yerkes Regional Primate Research Center.
In the current study, researchers combined the DNA and MVA vaccines in a prime-boost fashion. In theory, the DNA vaccine primes the immune response, alerting the body's defenses to a SHIV invasion and preparing against subsequent attacks. The MVA booster then kicks the immune system into high gear by mimicking a viral infection. The researchers hoped a combination regimen of the two vaccines would strengthen the immune system's ability to remember how SHIV looks and launch a rapid defense if infection occurred.
The investigators vaccinated four groups of Rhesus macaque monkeys, each group receiving different dosages of vaccines or different routes of injection. The monkeys were compared with four unvaccinated animals. The researchers waited seven months afPage: 1 2 3 Related biology news :1
Contact: Gregory Roa
NIH/National Institute of Allergy and Infectious Diseases
. Cancer vaccine based on pathogenic listeria bacteria shows promise targeting metastases2
. Pneumococcal vaccine reduces ear infections, pneumonia, new study shows3
. UC Irvine scientists to develop vaccine to combat bioterrorism threat from deadly bacteria4
. First clinical study of new pediatric croup vaccine shows safety, tolerability in adults5
. Protective gene may enhance vaccine responses6
. Protein vaccine fully protects mice from lethal aerosol challenge with ricin toxin7
. New glycan arrays discover autoimmunogenic activities of SARS-CoV: concern over monkey vaccine8
. Growing new breed of vaccine-producing plants to fight human diseases worldwide9
. Childrens Hospital Boston receives more than $10 million to help make smallpox vaccine safer10
. Triple-vaccine strategy stimulates strong HIV-specific immune response in monkeys11
. Herpes tool allows researchers to customize Alzheimers vaccine