Scientists have discovered that monkey cells have innate protection against infection with the human AIDS virus, a clue that may help explain why some people are susceptible to certain viral infections while others are not. The finding, reported in today's issue of the journal Nature, offers one of the first concrete examples of what researchers call an intracellular system of innate immunity and may open the door to the development of new antiviral therapies, the scientists said. The monkeys were protected from the virus by a mechanism that resides within cells and that is independent of the antibodies and white...