In another example of how the AIDS virus exploits its opponents, scientists have found that HIV uses immune system proteins to hitch rides on the antibody factories known as B cells.
Since B cells interact closely with T cells, the immune cells that HIV normally infects, the hitchhiking strategy may help the virus find potential host cells.
HIV infects a subset of T cells and, over time, reduces their number so much that a person's immune system can't fight off other infections. Consequently, scientists generally characterize AIDS as a T cell disease.
Yet scientists have long recognized that B cells also go awry in people with a full-blown HIV infection. "The B cells make a lot of antibodies . . . not targeted to anything," says Susan Moir of the National Institute of Allergy and Infectious Diseases in Bethesda, Md. The cells "are going into overdrive. It's almost like an allergic reaction," she says.