Designing vaccine candidates to elicit broadly neutralizing antibodies (bNAbs) has proved a major challenge. 

A minority of HIV-infected people generate such antibodies, but the average time for developing such responses is about 2½ years and only a small fraction of bNAbs protect against a broad range of HIV’s many different subtypes. The long—some say tortuous—development of bNAb responses entails a sort of continuous massaging of the immune system by the infecting virus.

Check out my article, "The Monkey Diaries," on IAVI Report's homepage, www.iavireport.org, which summarizes the spring meeting of the AIDS Vaccine Research Subcommittee. The meeting was devoted to developments in nonhuman primate research.

A prime-boost vaccination regimen using just Envelope—the protein from which the spikes on the outer surface of the virus are made—suffices to protect rhesus macaques from infection by simian immunodeficiency virus (SIV), but does not affect viral load in monkeys that do become infected, according to a recent study (Journal of Virology 2012, doi: 10.1128/JVI.00599-12). In the study, researchers used a so-called heterologous challenge, which is considered more realistic because the challenge virus differs from the type of virus carried in the vaccine. 

CD4+ T cells are central players in the body’s immune response. Often called “helper” cells, they orchestrate the assault on invading pathogens: They stimulate the development of antibodies in B cells, and send signals to CD8+ T cells, which detect and kill other infected cells, to make them better killers and to form memory cells. But CD4+ T cells are also the primary targets of HIV, which is why they are not believed to play a leading role in controlling infection by that virus. Instead, CD8+ T cells are thought to be the primary agents of HIV suppression, deploying so-called “death” molecules such as perforin, which pops open infected cells, and granzyme B, which forces them to commit suicide. 

Highly active antiretroviral therapy, or HAART, typically combines three antiretroviral drugs (ARVs) as a first line treatment for HIV infection. It is a very effective way to keep HIV replication under control. So effective, in fact, that the best drug combinations suppress HIV to undetectable levels in most patients.