By Arj Arjunan
Daily Bruin Contributor
Working to eventually discover an HIV vaccine for humans, UC San Francisco scientists have developed a vaccine protecting monkeys from transmitting a virus closely related to HIV.
The virus that the researchers in San Francisco were working with is Simian Immunodeficiency Virus which can kill a monkey in under three years.
In studies that lasted for just under a year, Dr. Raul Andino, an associate professor at UCSF, and Dr. Mark B. Feinberg, a former assistant professor at UCSF, tested the vaccine, which combines parts of a widely-used oral polio vaccine with genetic fragments of SIV. The monkeys that were injected with the vaccine containing SIV remained healthy for a year.
In recent years, work on a potential HIV vaccine has shifted focus from developing antibodies in the bloodstream to protecting the body at the points of infection – the mucosal surfaces of the rectum and genitals.
By using the polio vaccine, the scientists took advantage of its ability to trigger a strong immune response at the mucosal surfaces.
The promising outcome has scientists upbeat about prospects for developing a successful vaccine.
“There is logic in going with something that is proven,” said Dr. Peter Anton at UCLA’s Center for HIV and Digestive Diseases, speaking on the use of the polio vaccine. “The big development is that this had monkeys that showed no infection.”
Tempering his enthusiasm, he added that the manner in which HIV mutates makes it difficult to concentrate on any one vaccine.
“No one would take bets because the virus is so difficult and evolving,” he said.
Charles Price, an associate of Anton, who is currently helping to organize the volunteer campaign for a similar study at UCLA, pointed to the close course of SIV in monkeys and HIV in humans as reason to regard the success of the oral vaccine as promising.
“The promising thing (about the experiment’s results) is that any oral vaccine takes away the need to have it professionally administered,” he said, pointing out practical ways to apply to any potential vaccine.
While the UCSF scientists’ work concentrated on an oral vaccine, Anton’s work at UCLA currently focuses on whether different areas of vaccine injection enhance mucosal responses at the most common site of infection, the pelvic area.
The study tests HIV vaccines based on existing smallpox and canary pox vaccines. It measures the response of the immune system’s antibodies and T-cells against the pieces of HIV present in the vaccines.
Because the vaccines use only pieces of the HIV virus they pose no risk of infecting volunteers.
Trials on primates indicate that the area of injection markedly influenced the immune response at the mucosal surface, Anton said.
So far, the human trials have involved injections in the deltoid area and now testing focuses on the potential benefits of injecting in the groin.
Anton suggested that using these vaccines rather than the polio vaccine promised exposure to more genetic fragments of HIV that could potentially offer stronger immunity.
“The polio vaccine is smaller, so you can get fewer genes in there,” Anton said.
Trials at UCLA are still in the first of three phases. Phase one tests whether vaccines are safe for people to take.
Right now, Price and Faith Landsman, another vaccine trial organizer working with Anton, are seeking paid volunteers for the ongoing Experimental HIV Vaccine and Immunology Study.
The trials will take blood samples 15 times over an 18-month period and involve a sigmoidoscopy that takes sample of rectal tissue to measure the immune response of volunteers to the vaccines.
With reports from Daily Bruin wire services.