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New study shows that antibodies seen in RV144 may also correlate with lower risk of infection from multiple HIV subtypes

February 5, 2014
Research confirms results from the RV144 correlates study and provides link to planned studies

In a study published in PloS One February 4, researchers show that vaccine-induced antibodies targeted at a particular region of the HIV virus, V1V2, correlate with reduced risk of infection but also react not just with the HIV subtype that was most commonly seen in RV144 (the Thai trial), but also with multiple HIV subtypes that circulate in other parts of the world.

This research was lead by MHRP collaborator, Dr. Susan Zolla-Pazner of the Veterans Affairs New York Harbor Healthcare System. Dr. Zolla-Pazner was part of the team led by researchers from Duke and MHRP that published the results of the correlates studies in the New England Journal of Medicine in 2012 that detailed clues to why the vaccine tested in the RV144 trial protected some volunteers.

In the correlates studies, researchers found that immunoglobulin G antibodies that bind to the V1/V2 region of HIV’s Envelope protein correlated with lower infection rates among those who were vaccinated. Additional findings, later published in Nature, reinforced that antibodies directed at the V1V2 region played a role in reducing the risk of infection. 

While this study confirms the results of the correlates studies, the majority of HIV infections (89%) that occurred in the RV144 trial and studied up to this point were caused by HIV-1 CRF01-AE—the most common subtype of HIV circulating in Thailand. Researchers have now shown that vaccine-induced antibodies also react with the same region of the HIV virus from subtypes A, B, C and AE. 

Researchers noted an especially significant association between the antibody reaction with subype C and a reduced risk of infection. This finding provides a link between the RV144 study in Thailand and the planned future studies in southern Africa that will use a similar vaccine regimen to that used in RV144, but adjusted for subtype C.