Immune System Protein Makes HIV More Infectious in Humans, Study Says

"Cyclophilin A Renders Human Immunodeficiency Virus Type 1 Sensitive to Old World Monkey but Not Human TRIM5 Antiviral Activity," Journal of Virology: Greg Towers of University College London and colleagues find that a human immune system protein called cyclophilin A alters the form of HIV particles and makes them more infectious, New Scientist reports (Hooper, New Scientist, 5/6). Researchers infected cells from "Old World" monkeys and from humans with HIV-1 to analyze the protein's effect on the virus. The monkey cells, which contain cyclophilin A and an immune system protein TRIM5-alpha, stopped the virus from replicating. However, cyclophilin A in the human cells made HIV more infectious. "[T]he virus is using cyclophilin A to help it replicate," Towers said (Hooper, New Scientist, 5/6).