New Findings to Help HIV Scientists Establish ‘Template’ For Potent Antibodies


Source: International AIDS Vaccine Initiative

Summary: In a new study, researchers trying to understand how some human beings generate powerful HIV-blocking antibodies. This study can help to design a potential HIV vaccine.


During a natural HIV infection, a small group of individuals (nearly 10%) generates powerful broad and potent antibody responses. Those antibodies which are capable of neutralizing a large fraction of global HIV-1 isolates are called as broadly neutralizing antibodies (bnAbs), and are thought to be very much desirable for developing an effective HIV-1 vaccine. Researchers from International AIDS Vaccine Initiative (IAVI) and The Scripps Research Institute (TSRI) in a new study are trying to understand how some human beings generate powerful HIV-blocking antibodies. In this study, they described the bnAb lineage targeting the Env V2 apex of the HIV surface and Ab-Env co-evolution which led to the development of neutralization breadth. The study findings were published in the journal Immunity.

Neutralizing antibodies development is critical to HIV vaccine design

This graphical abstract depicts the co-evolution of HIV and broadly neutralizing antibodies in an African donor, including the viral features found to promote antibody breadth. Credit: © Elise Landais, International AIDS Vaccine Initiative

The Research team selected an African individual infected with HIV subtype-A from the samples out of IAVI’s Protocol C epidemiological study. This volunteer (PC64) developed HIV broadly neutralizing antibodies targeting the vulnerable V2-apex site on HIV’s surface. This specific type and bnAbs are very potent and effective neutralizers of HIV. Their neutralization breadth blocks a majority of the HIV strains. An advanced technique, next-generation sequencing was applied and the researchers were able to watch these bnAbs develop in reverse. A series of snapshots were taken which depict the interplay of PC64s immune response with the volunteer’s infecting virus over time. Using these images they observed that certain viral changes promoted antibody neutralization breadth.

The researchers said that these findings were consistent and complementary with the previous work by IAVI and could offer a possible template for developing an HIV vaccine but further research is needed to achieve an optimal design.

Senior Research Scientist, Elise Landais said, “Uncovering the process by which neutralizing antibodies develop is critical to HIV vaccine design”, “A small fraction of people living with HIV can naturally produce exceptionally powerful and broad antibodies that could prevent HIV from infecting their immune cells, but not until several years post-infection – long after that protection can help them. But it is of enormous interest to vaccine researchers.”


More Information: Elise Landais et al, “HIV Envelope Glycoform Heterogeneity and Localized Diversity Govern the Initiation and Maturation of a V2 Apex Broadly Neutralizing Antibody Lineage”, Immunity (2017). DOI: http://dx.doi.org/10.1016/j.immuni.2017.11.002


 

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