Zephyr Foundation

Researchers are looking into the antibodies that provide natural immunity

In a desperate attempt to reverse 25 years of failure to develop an AIDS vaccine, scientists have a new approach: studying people who have been infected with HIV for many years without any signs of ill-health. The patients' secret? Natural immunity.

The researchers have investigated the virus-fighting antibodies found in the blood of six long-term survivors of HIV whose own immune systems appear to be capable of shrugging off the virus. Results of tests show that a prototype vaccine made from several of the antibodies produced by those long-term survivors can prevent HIV from infecting human cells. The experiments have been successful on human cells growing in a test tube. Now further trials are planned on laboratory animals and human volunteers.

The search for an AIDS vaccine has suffered a series of setbacks over the years. The most recent was the failure of the most promising potential vaccine, in a major clinical trial by the US drug company Merck. The trial, which had involved thousands of volunteers, had to be abandoned at the end of 2007 because of fears that the trial vaccine might in fact make patients more susceptible to AIDS.