Today I had a chance to talk to Mario Roederer, a T-cell immunologist at the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases and a co-organizer of the “Protection from HIV” track at the Keystone meeting. He said the goal of the track was “to really expose the vaccine community to the microbicides people and vice versa because these approaches will have to be undertaken together in the future.” Roederer, who is married to microbicide researcher Laurel Lagenaur, said that as microbicides are becoming more specific, they are more similar to vaccines, which is why it is time that vaccinologists and microbicide researchers interact.
In the last two years, several research groups have reported the isolation of a slew of new broadly neutralizing antibodies (bNAbs) that are more potent than the handful of such antibodies that had been known until then. Among them was VRC01, a bNAb isolated by researchers at the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Diseases, which can neutralize over 90% of currently circulating HIV-1 strains (see Raft of Results Energizes Researchers, IAVI Report, Sep.-Oct. 2009). VRC01 and other HIV-specific bNAbs also have an unusually high degree of affinity maturation, which means that they are quite different from the germline version of the antibody that they are derived from (see Vaccines to Antibodies: Grow Up!, IAVI Report, July-Aug. 2010).
Three years ago, the Center for HIV/AIDS Vaccine Immunology (CHAVI) began looking at a small cohort of hemophiliacs who had been exposed to HIV but remained uninfected despite receiving Factor VIII concentrates derived from large pools of blood plasma collected from donors, some of whom were infected with HIV (see Individual Armor Against HIV, IAVI Report, July-Aug. 2008).
Even when biomedical interventions against HIV work in clinical trials, as they have lately for several HIV prevention strategies, scientists don’t always know why. To borrow an analogy from the breathtaking backdrop of the annual Keystone conference this week, identifying the correlates of immune protection is a Nordic slog through the wilderness, not an Alpine run.
The antiretrovirals (ARVs) tenofovir and Truvada—a combination of tenofovir and emtricitabine—have received the lion’s share of attention lately for their role in preventing HIV infection, but researchers are experimenting with other ARVs that may also be effective topical pre-exposure prophylaxis (PrEP) agents.