Tracking HIV “Superinfection” Between Partners (Video)

NIAID Now | March 22, 2018

An illustration depicts HIV superinfection, a condition in which a person who is already living with one strain of HIV acquires another strain of the virus.

Credit: NIAID

Most people living with HIV have a single genetic strain of the virus, but in certain cases, a person can acquire a second strain of HIV—a condition known as HIV superinfection. In a new study published online today in the Journal of Infectious Diseases, NIAID researchers and scientists at the Uganda Virus Research Institute describe a case of HIV superinfection they were able to identify with unique precision.

Fortunately, people who experience HIV superinfection respond well to standard treatments. However, experts say insights surrounding HIV superinfection can inform HIV vaccine development. Of particular interest, researchers say, is why some people living with HIV may be vulnerable to HIV superinfection.

In this study, researchers followed people living with HIV in Uganda who were in long-term sexual relationships with a member of the opposite sex living with a different genetic strain of HIV. By regularly collecting blood samples from each member of these relationships and screening for new genetic variants of HIV, the researchers were able to pinpoint exactly when one female volunteer was superinfected by her husband’s strain of HIV.

To determine why this woman may have been susceptible to HIV superinfection, researchers took a closer look at the immune components of her blood. Many people living with HIV develop antibodies naturally over time that neutralize HIV and may protect people from reinfection with a similar strain of the virus. The woman who experienced HIV superinfection in this study did have several types of neutralizing antibodies to viruses similar to her original genetic strain of HIV. However, her immune system did not produce antibodies effective against the strain of HIV transmitted by her husband, possibly leaving her vulnerable to superinfection.

Researchers say these findings further support ongoing efforts to develop vaccines and other HIV prevention strategies that protect against multiple strains of HIV and ensure candidate vaccines elicit an immune response stronger than that which occurs naturally after HIV infection.

The research team was led by Andrew D. Redd, Ph.D., of the NIAID Laboratory of Immunoregulation; Nicole Doria-Rose, Ph.D., at the NIAID Vaccine Research Center; and Deogratius Ssemwanga, Ph.D., and Pontiano Kaleebu, M.D., Ph.D., at the Uganda Virus Research Institute.

In a short video, Dr. Redd explains the case and its significance to HIV prevention research:

This video is part of the NIAID Video SNiP series. In each SNiP, a NIAID scientist explains a recent research advance and its implications in two minutes or less.

Reference: D Ssemwanga et al. Characterization of the neutralizing antibody response in a case of genetically linked HIV superinfection. Journal of Infectious Diseases DOI: 10.1093/infdis/jiy071 (2018).

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