David Brown in the Washington Post:
Some long-term survivors of HIV infection produce rare and extremely potent antibodies that keep the disease from progressing to AIDS, and might point to a way to protect uninfected people from the virus, researchers reported yesterday in the closing hours of the 17th International AIDS Conference in Mexico City.
The antibodies, against a particular part of a much-studied HIV protein called gp120, might prove useful as a microbicide for blocking infection during sexual intercourse. If researchers could find a way to prompt the immune system to make its own supply of the antibodies before encountering the virus, they would have a vaccine…
The search for both an AIDS microbicide and a vaccine has been particularly frustrating. None are in use, and some candidates tested in recent years have turned out to increase the risk of infection.
The antibodies described yesterday attack a small and crucial region of HIV’s outer shell where the virus binds to its chief prey, immune-system cells called lymphocytes. Acting as an enzyme, the antibody clips the attachment point, and falls away undamaged and ready to do the job again.
More here.