Antibodies That Can Prevent HIV-1 Infection Remain Detectable Even at Low Antigen Levels

A recent study evaluated the longevity of neutralizing antibodies in individual living with HIV type 1 (HIV-1) infection. The current belief is that an HIV-1 vaccine can only be effective if it produces the antibodies in those who are vaccinated, and the new findings improve the understanding of the dynamics of such antibodies and could help build the foundation for additional research on an HIV-1 vaccine.¹

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Despite effective drugs that are the foundation for treating the HIV-1 infection and can effectively prevent the transmission of the virus, 1,200,000 individuals contract HIV infection annually, according to the investigators. Broadly neutralizing antibodies (bNAbs) can help prevent HIV infection, and researchers are trying in induce bNAbs through a vaccination in humans; however, thus far, it has proven to be difficult.

Researchers note that it is unclear how long broadly neutralizing antibodies remain in humans important to develop successful strategies for an HIV-1 vaccination. The study, which was published in Nature Medicine, evaluated the HIV-1 antibody response in 2354 people living with HIV who were both on and off antiretroviral therapy (ART) by assessing neutralizing immunoglobulin G. The researchers were able to identify various factors that cause patients to form neutralizing antibodies naturally and which participants were considered elite neutralizers (individuals living with HIV-1 who were able to build up a potent and broadly neutralizing antibody response). Further, the researchers determined bNAbs half-lives of 9.3 and 16.9 years in individuals with no or low-level viremia, respectively, and 4 years in individuals who newly initiated ART.^1,2

The study authors found that the antibody response in patents decrease over time; however, bNAbs continue to be detectable, even at low antigen levels. The authors note that this is a significant finding that indicates that a potential HIV-1 vaccine can trigger a permanent response.

“We were able to show that the HIV-1 neutralization activity in patients strongly depends on the amount of virus in patients,” said Philipp Schommers, MD, PhD, head of the laboratory for antiviral immunity at the Department of Internal Medicine of the University Hospital Cologne, in a press release. “While this dependence could be investigated in other infectious diseases, such as COVID-19, shortly after the initial description of the disease, the longevity of neutralizing antibodies in HIV-1 had not yet been shown in large studies.”¹

References

1. University of Cologne. Another step toward the HIV-1 vaccine: Dynamics of neutralizing antibodies. News release. November 14, 2023. Accessed November 20, 2023. https://www.eurekalert.org/news-releases/1008016

2. Schommers, P., Kim, D.S., Schlotz, M. et al. Dynamics and durability of HIV-1 neutralization are determined by viral replication. Nat Med (2023). doi:10.1038/s41591-023-02582-3