The second immune system category is adaptive B cell immunity, a slower response that creates powerful, pathogen-specific antibodies and provides lasting immunity. The body's normal response to infection is to produce adaptive antibodies that target only the invading virus or other pathogens. Many widely used non-HIV vaccines "train" adaptive antibodies to seek out a unique protein on the protective outer coating of viruses. HIV researchers have attempted to induce broadly neutralizing antibodies ?long-lived, HIV-specific antibodies that can kill all or most HIV strains ?with a similar vaccine design.
Some broadly neutralizing antibodies have been isolated from HIV-infected humans, although the antibodies are rare, with less than five identified. "We know these antibodies can exist, but we have not been able to give a vaccine to people or animals that stimulates the production of these types of antibodies," said Haynes, who has studied HIV vaccines for 15 years.
In their experiments, Haynes and his colleagues demonstrated that some of these rare broadly neutralizing antibodies are actually polyspecific autoantibodies that react with many proteins, including one's own tissues, like the antibodies made by innate B cells. In laboratory tests, the antibodies reacted with multiple types of human molecules, most prominently with a fat molecule called cardiolipin.
"It appears the most vulnerable spots on the outer coat protein of HIV, to which the most protective antibodies bind, are the target of autoantibodies that also react with normal human tissues and are normally destroyed by the immune system," Haynes said.
Haynes, an AIDS researcher who has also studied autoimmune diseases, began to focus on possible similarities between HIV infection an