Antibodies with loops could lead to an effective HIV vaccine according to new research published in the Proceedings of National Academy of Sciences. With an estimated 1.2 million people living with HIV infection in the U.S., a new vaccine could lower the rate of new infections high risk groups like gay, bisexual, and other men who have sex with (MSM).
In high-risk groups, the CDC recommends pre-exposure prophylaxis (PrEP) therapy that involves taking medications like Truvada along with safe sex practices to prevent the HIV virus. While Truvada has been shown effective at reducing the rates of new HIV infections in at risk groups, the news of the first man to become infected while on this breakthrough preventative medication signals the need for better therapies that protect against the virus.
Vaccine Antibodies that Kill the HIV Virus
Researchers at Vanderbilt University focused on identifying antibodies that are toxic to the HIV virus in a three-phase study. The breakthrough discovery lead researchers to identity naturally occurring loop-like structures that bind to HIV and inhibit the virus from spreading to other healthy cells.
Using a sophisticated modeling program for molecules, the research team was able to identify a chain of amino protein structures, HCDR3, that bind to the HIV virus. Through further analysis, researchers identified 28 distinct unique amino acids within HCDR3 and optimized the arrangement of the sequence structure. This process was then followed by choosing the selected HCDR3 proteins and fusing them onto PG9, a known antibody that neutralizes HIV. Researchers uncovered that when PG9 is reengineered with selected HCDR3 proteins, the antibody is able to neutralize and kill the HIV virus. In essence, reengineered PG9 could make the HIV vaccine a reality in the near future.
This breakthrough is only the beginning stage in developing an effective preventative measure against the HIV virus. Researchers noted that the HCDR3 protein structures are only present in 1/3 of people and that it takes the body one year to produce the HIV neutralizing antibodies. The HCDR3 protein discovery, along with existing preventative drugs like Truvada is providing hope that researchers will soon develop an effective HIV treatment that reduces the rate of infections in high-risk groups.