Promising new antibodies could prevent hiv-1 infection
A team of scientists at the Texas Institute of biomedical research has focused on a new defense against HIV-1. Hiv-1 is a virus that causes AIDS. Led by medical doctor Ruth Ruprecht, the team used animal models to show for the first time that an antibody called immunoglobulin M (IgM) is effective in preventing infection after mucosal HIV exposure. Worldwide, an estimated 90 percent of new HIV-1 cases are due to exposure to mucosal cavities, such as the rectum or the inner wall of the vagina."IgM is some kind of forgotten antibody," said Dr. Ruprecht, a scientist, and director of the AIDS research program at the Texas Institute of biomedical research. "Most scientists believe its protection is too short to be used as any protection against invasive pathogens such as HIV-1."
The study was published in the July 17, 2018, issue of the journal AIDS. This article, listed as a "fast track", suggests that these new and exciting data should receive special attention.
Rhesus macaques from the southwest national primate research center at the University of Texas biomedical science are models for studies in vivo. The scientists first treated the animals with a human-made IgM, which is naturally produced by plasma cells under the epithelium (the surface lining of the body's cavity). Half an hour later, the same animal was infected with SHIV. Four of the six animals treated this way are fully protected by the virus. The animals were observed for 82 days.
Dr. Ruprecht's team found that the use of IgM antibodies can lead to so-called immune rejection. IgM binds the virus together, preventing it from crossing the mucosal barrier and spreading to other parts of the body. The technique of introducing preformed antibodies into the body to produce immunity is called passive immunity.
IgM has a high affinity for its antigens, "catching them quickly and not releasing them," Dr. Ruprecht explained. "Our study is the first to reveal the protective potential of mucosa against HIV-1 IgM. IgM is five times more capable of binding to virions than a standard form of antibody called IgG. It basically opens up a new field of research. IgM can do more than it is given.
In an accompanying editorial, Dr. Ruprecht "set off a new wave in assessing the activity of IgM antibodies in neutralizing HIV-1." [she and her team] have largely broadened their vision of neutralizing the HIV-1 antibody, a single or combined drug that could be used to prevent and treat HIV-1.
The study used P51 OD011133 from the office of the national institutes of health's basic research program, funded by the southwest national primate research center.
