A small minority of individuals infected with HIV — about one in 300 –Â are naturally able to suppress viral replication with their immune systems, and can keep HIV levels extremely low for years. Doctors have named these individuals “elite controllers.”
“These individuals have naturally achieved the outcome sought by HIV vaccine researchers worldwide. Â Studying them will ultimately inform the design of a more effective HIV vaccine,” saysÂ Vincent Marconi, a physician-scientist at Grady Health System’s Infectious Disease Clinic on Ponce de Leon and an associate professor in the Emory School of Medicine.
Marconi is a co-author (along with investigators at over 200 institutions) on a genomics study of elite controllers published Thursday in Science Express. Led by Bruce Walker at Massachusetts General Hospital and Paul de Bakker at the Broad Institute and Brigham and Women’s Hospital in Boston, the team of researchers scanned through the genomes of close to 1,000 elite controllers and 2,600 people with progressive HIV infection. They identified several sites linked with immune control of HIV, all in a region encoding HLA proteins.
HLA proteins play key roles in activating T cell immunity, and are also necessary for the development of T cells. They grab onto segments of proteins, called peptides, inside the cell and carry them to the cell membrane. In the right context, certain viral peptides can mark infected cells for destruction by “killer” T cells.
Previously, MGH/MIT researchers theorized that people with certain forms of their HLA genes develop T cells with a restricted repertoire, yet broader activity. Their T cells would be more likely to still recognize HIV when the virus mutates. A drawback is that these individuals may have a higher risk for developing autoimmune diseases.Â The theory is described in more detail in this Nature News article.
Marconi is continuing his part of this research into what makes elite controllers’ immune systems special, which he began at the Department of Defense Infectious Disease Clinical Research Program, in collaboration with Eric Hunter, co-director of Emory’s Center for AIDS Research, and research associate Ling Yue at Emory Vaccine Center. The research is supported by the Center for AIDS Research and the National Institute of Allergy and Infectious Diseases.