Scientists at Texas Biomededical Research Institute have zeroed in on a new defense against HIV-1, the virus that causes AIDS. Led by Ruth Ruprecht, M.D., Ph.D., the team used an animal model to show for the first time that an Immunoglobulin M (IgM) antibody was effective in preventing infection after mucosal AIDS virus exposure. Worldwide, an estimated 90% of new cases of HIV-1 are caused through exposure in the mucosal cavities like the inside lining of the rectum or vagina.
Rhesus monkeys served as models for the in vivo study. Scientists first treated the animals with a recombinant polymeric monoclonal IgM generated from the neutralizing monoclonal IgG1 antibody. IgM antibodies naturally produced by plasma cells located under the epithelium, the surface lining of body cavities. Half an hour later, the same animals were exposed to SHIV (simian-human immunodeficiency virus). Four out of the six animals treated this way were fully protected against the virus. The animals were monitored for 82 days.
Dr. Ruprecht’s team found that applying the IgM antibodies resulted in what is called immune exclusion. IgM clumped up the virus, preventing it from crossing the mucosal barrier and spreading to the rest of the body. The technique of introducing pre-formed antibodies into the body to create immunity is known as passive immunization.
The study is published in the July 17, 2018 edition of the journal AIDS. A link to the press release by Texas Biomed and the article is here https://www.txbiomed.org/news-press/news-releases/research-shows-a-promising-new-class-of-antibodies-protects-against-hiv-1-infection/