New Delhi, July 8 -- Scientists have triggered protective levels of HIV-fighting antibodies in monkeys with unmodified immune systems for the first time, a new study in Nature reports - a milestone more than a decade in the making. While only one primate produced antibody levels expected to guard against infection, and fewer than half showed any neutralising response, researchers said the result mattered less for its scale than for how it was achieved: through a process called germline targeting. Most vaccines work by showing the immune system a piece of a virus and hoping that, among the countless responses it could make, a useful one turns up. Germline targeting reverses that: it starts from the antibody the vaccine wants the body to produce, finds the rare cells already capable of becoming it, and trains them there directly - closer to recruiting the person who can already do the job than advertising the vacancy and hoping the right applicant shows up. "How could we flip the whole immune response on its head so the rare responses become the common responses? That was a critical challenge we faced," said Shane Crotty, chief scientific officer at La Jolla Institute for Immunology, who co-led the research with Scripps Research's William Schief, said in a statement....