An antibody called “Immunoglobulin M (IgM)” has been shown to be effective in preventing HIV infection after mucosal exposure to the virus. Results that are (finally) very encouraging in the fight against AIDS.
A promising new class of antibodies would protect against HIV. This is the result of a recent study, published in the journal AIDS. Led by Ruth Ruprecht, a team of scientists demonstrated for the first time that an antibody called “Immunoglobulin M (IgM)” was effective in preventing infection after mucosal exposure to the AIDS virus. It is estimated that 90% of new HIV cases are caused by exposure to the mucosal cavity virus such as the lining of the rectum or vagina.
“So far, IgM has been a sort of forgotten antibody,” says Ruth Ruprecht, director of Texas Biomed’s AIDS Research Program. “Most scientists thought that its protective effect was too short to be used as a shield against such an invasive pathogen as HIV.”
A new field of research
Nevertheless, the researchers decided to test its effectiveness on rhesus monkeys. They first treated the animals with human IgM. Half an hour later, the same animals were exposed to the AIDS virus. 82 days later, four out of six monkeys were completely immune to HIV.
Specifically, IgM has “agglutinated” or “absorbed” the virus, preventing it from crossing the mucosal barrier and spreading to the rest of the body. “Our study reveals for the first time the protective potential of IgM. IgM captures virus particles five times better than the standard antibody form, which opens up a new field of research,” says Ruth Ruprecht.
The global HIV epidemic is not nearing completion
The latest report from UNAIDS recalls that new infections are on the rise in around 50 countries. In Eastern Europe and Central Asia, the annual number of new HIV infections has doubled in the last 20 years. Globally, HIV infections have declined by only 18% in the last seven years, from 2.2 million in 2010 to 1.8 million in 2017. Although this figure represents almost half of the number of new infections compared to 1996, when this number was highest (3.4 million), the decline is not fast enough to reach the target of less than 500 000 new HIV infections by 2020.
“The global HIV epidemic is not nearing completion and the prevailing rhetoric about the end of AIDS, fueling dangerous complacency, may have precipitated a decline in the determination to fight the virus in the first place,” say the authors.