A study by researchers at the National Institute of Allergy and Infectious Diseases and Duke University helps explain why the candidate vaccine used in the HVTN 505 clinical trial was not protective against HIV infection despite robustly inducing anti-HIV antibodies: the vaccine stimulated antibodies that recognized HIV as well as microbes commonly found in the intestinal tract, part of the body's microbiome. The researchers suggest that these antibodies arose because the vaccine boosted an existing antibody response to the intestinal microbiome, which may explain why the HVTN 505 vaccine candidate did not perform well. Understanding why the candidate vaccine did not protect against HIV infection will inform ongoing vaccine research efforts against HIV and other infectious diseases.
WB Williams et al. Diversion of HIV-1 vaccine-induced immunity by gp41-microbiota cross-reactive antibodies. Science DOI:10.1126/science.aab1253 (2015).
NIAID Director Anthony S. Fauci, M.D., and John Mascola, M.D., director of NIAID's Vaccine Research Center and one of the study authors, are available to discuss the findings.