How monkeys block HIV

HIV-1 is unable to replicate in Old World monkeys, even though it can enter their cells. In 2004, Joseph Sodroski at Dana-Farber Cancer Institute in Boston and his colleagues identified the factor responsible. They transduced human cells with a complementary DNA (cDNA) library prepared from rhesus monkeys. Resistant cells commonly harbored cDNA for the cytoplasmic body component TRIM5α. The research revealed an intracellular immunity mechanism to viruses "we didn't realize existed before," Sodroski says. TRIM5α possesses at its C-terminal end a domain with variable regions on it "similar to immunoglobulin," he adds.