Surprising Trait in Anti-HIV Antibodies

Surprising Trait in Anti-HIV Antibodies

In the journal Immunity, researchers describe four prototype antibodies that target a specific weak spot on the virus. Guided by these antibodies, the researchers then mimicked the molecular structure of a protein on HIV when designing their own potential HIV vaccine candidate.

The researchers carried out a series of experiments involving virus modifications, protein and antibody engineering. They found that four antibodies targeted a single spot on HIV's surface called the V2 apex. This was significant because the V2 apex could be recognized by these antibodies on about 90 percent of known HIV strains -- and even related strains that infect other species. A vaccine targeting this region could protect against many forms of the virus.

Investigating further, the researchers noticed that two of the four antibodies had an unusual feature that could prove important in vaccine design.

The immune system usually begins its fight against infection by activating immune B cells that express 'germline' forms of antibodies, on their surface, to bind invading pathogens. Germline antibodies rarely bind viruses very effectively themselves; instead, they are precursors for more developed antibodies, which mutate and hone their response to the invader.

Yet in the new study, two of the antibodies did not need to mutate to bind with the V2 apex; instead, these antibodies used part of their basic germline structure, encoded by non-mutated genes. This means any patient with HIV should, in theory, have the ability to kick-start the right immune response.