An international research team, including scientists from the University of Rochester, discovered the mechanism by which a protein protects some immune cells from HIV. This finding could lead to more effective treatments for patients with HIV as well as give insight into how other pathogens attack the body. The protein, SAM domain and HD domain-containing protein 1 (SAMHD1), is found in microphages, a type of white blood cells, and dendritic cells. It works by starving HIV-1 of the molecular building blocks required to replicate. Researchers also discovered that due to another protein, Vpx, which destroys SAMHD1, HIV-2 can infect microphages. Despite this advantage, HIV-1 is still the more virulent form. “The work suggests new ways to target virus replication in macrophages, a critically important cell population that serves as a key reservoir of virus infection and a contributor to HIV-induced disease,” said Baek Kim, one of three corresponding authors of the paper.