Team discovers HIV antibodies
Research could lead to AIDS vaccine

By THOMAS H. MAUGH II
Los Angeles Times

After 15 years of futile search for a vaccine against the AIDS virus, researchers are reporting the tantalizing discovery of antibodies that can prevent the virus from multiplying in the body and producing severe disease.

They do not have a vaccine yet, but they may well have a road map toward the production of one.

A team headquartered at the Scripps Research Institute in San Diego reports in the journal Science that they have isolated two so-called broadly neutralizing antibodies that can block the action of many different strains of HIV, the virus responsible for the AIDS pandemic.

Crucial to the discovery is the fact that the antibodies target a portion of HIV that researchers had not previously considered in their search for a vaccine. Moreover, the target is a relatively stable portion of the virus that does not participate in the extensive mutations that have made HIV able to escape from antiviral drugs and previous experimental vaccines.

"This is opening up a whole new area of science," said Dr. Seth Berkley, president and chief executive of the International AIDS Vaccine Initiative, which funded and coordinated the research.

At least 33 million people worldwide are currently infected with HIV and at least 25 million have died from AIDS, according to the World Health Organization. Two large trials of experimental vaccines have failed, the most recent, in 2007, because the vaccine apparently made people more susceptible to infection.

To find the neutralizing antibodies, researchers went to Thailand, Australia and Africa, collecting blood samples from more than 1,800 people who had been infected with HIV for at least three years without the infection proceeding to severe disease. Such individuals are most likely to produce antibodies that interfere with the replication of the virus.

Researchers at Monogram Biosciences Inc. in South San Francisco then studied the samples most resistant to infection. A team from Theraclone Sciences in Seattle then isolated the antibodies responsible for the resistance.

They ultimately isolated two antibodies, called PG9 and PG16, from one African patient. The antibodies were able to block the activity of about three-quarters of the 162 separate strains of HIV they tested it against.

Immunologist Dennis Burton of Scripps and his colleagues then showed that the antibodies bind to regions of two proteins on the surface of the virus, called gp120 and gp41, that help the virus invade cells. Significantly, these regions had never been considered as targets for vaccines.

Researchers still have a long way to go to produce a vaccine, however. The antibodies themselves could potentially be used as a treatment for infected patients who develop severe disease.

But the long-term hope is to find molecules, either synthetic or natural, that can stimulate the body to produce the broadly neutralizing antibodies. Such molecules could potentially be the basis for a successful vaccine.

Discovery offers new hope for an AIDS vaccine

CTV.ca News Staff
September 4, 2009

The search for an HIV vaccine has taken a major step forward with the discovery of two new immune system tools as well as a vulnerable spot on the virus that causes AIDS.

Researchers have announced they've found two new antibodies that attack the AIDS virus, opening the door to a way to develop a vaccine to the incurable virus.

Researchers led by Dennis Burton of The Scripps Research Institute in La Jolla, California, made the discovery after sifting through the blood of 1,800 people infected with AIDS.

They identified two antibodies that seem to neutralize the virus, dubbing the immune system fighters PG9 and PG16. They are the first new HIV antibodies to have been identified in more than 10 years of AIDS research and appear to be 10 times more effective at disarming the virus than already-discovered antibodies.

At the same time, the researchers found a new weak spot on the virus that the antibodies attack, they report in the journal Science. The researchers found that the antibodies target a part of the "spike" that viruses use to infect cells.

"So now we may have a better chance of designing a vaccine that will elicit such broadly neutralizing antibodies, which we think are key to successful vaccine development," said Burton.

Wayne Koff of the International AIDS Vaccine Initiative, or IAVI, which sponsored the study, said the findings are an exciting advance toward the goal of an effective AIDS vaccine "because now we've got a new, potentially better target on HIV to focus our efforts for vaccine design," he said.

IAVI director Dr. Seth Berkley said the findings will not lead directly to a vaccine. But he says they offer a new way to design one.

While treatments to slow down AIDS infections have been developed in recent years, there is still no cure. Researchers trying to design a vaccine have come up empty-handed, hamstrung by the fact that the virus infects the very immune cells that are supposed to protect the body.

Most frustrating, the virus is constantly mutating, so that any one person can be infected with millions of different versions, each one appearing different to the immune system.

But Burton's team says the newly discovered antibodies are effective against a broad array of HIV strains that span nearly every continent. He says they don't appear to attack every strain but in the lab experiments, they did attack about 80 per cent of the strains they tested, which he says is exceptional considering how variable HIV viruses are.

Vaccines work by training the immune system to generate antibodies against foreign pathogens, such as bacteria and viruses. Antibodies bind or latch on to specific portions of a virus and then prevent that virus from infecting healthy cells.

Eventually, the antibody also targets the invading virus for destruction by calling in other immune cells, known as T cells.

While it may be possible to use antibodies to treat AIDS, by creating an immunoglobulin or gamma globulin, such as the one often used to treat early hepatitis, the eventual goal is a vaccine that could stop the virus from infecting a person in the first place, Berkley said.

According to the International AIDS Vaccine Initiative, more than 20 million people have died so far in the AIDS pandemic and about 33 million are living with HIV.

HIV-AIDS rate is increasing across Florida

HIV/AIDS is at a `critical' level for men in Florida, a new study has found.

BY FRED TASKER
Miami Herald
September 3, 2009

MIAMI -- HIV/AIDS among Florida's men has reached critical levels, according to a new state report, and the highest rate in any racial/ethnic groups was in Miami-Dade County.

Overall, one in every 123 adult men in Florida was living with HIV/AIDS through 2008, said the report called Man Up: The Crisis of HIV/AIDS Among Florida's Men, by the Florida Department of Health. Overall, 90,000 Floridians age 13 years and over were living with HIV//AIDS. And 72 percent of them were men.

Overall, African-American men are still hardest hit by HIV/AIDS in terms of the overall infection rate. Statewide, one in 43 African-American men was living with HIV/AIDS. compared with one in 117 Hispanic men and one in 209 non-Hispanic men.

However, the proportion of African Americans among newly infected men declined dramatically between 1999 and 2008.

In 2008, persons living with HIV/AIDS included:

• In Miami-Dade, one in 60 non-Hispanic white men, one in 82 Hispanic men and one in 29 African-American men.

• In Broward, one in 76 non-Hispanic white men, one in 98 Hispanic men and one in 42 African-American men.

Florida's population is 61 percent non-Hispanic white, 22 percent Hispanic, 15 percent African-America and 3 percent other.

Florida's share of the nation's HIV/AIDS cases remains high. In 2006, Florida had 5,550 new infections -- nearly 10 percent of the 56,500 new cases in the entire country.

It's important to know where to target messages about fighting HIV/AIDS, the report said, because ``HIV transmission can be prevented with successful behavior change among those already infected.''

``This report seeks to encourage men to `man up' and take responsibility for the consequences of their sexual actions.''

It urged Florida's men to ``be faithful, use condoms, get tested for HIV, be honest with sexual partners, seek treatment, get an annual physical exam and challenge societal expectations of men that may encourage unsafe behaviors .''