US scientists have found an antibody that acts against 30 of 36 strains of influenza, the latest discovery in the hunt for a universal treatment and a vaccine, said a study published Monday. The new broadly neutralizing antibody, called CH65, can stick to the surface part of the flu virus known as hemagglutinin which mutates every season, forcing medical experts to regularly come up with a new vaccine. It was found in cells from a human volunteer who was given the flu vaccine for 2007, said the study in the Proceedings of the National academy of Sciences. \"What this tells us is that the human immune system can fine-tune its response to the flu and actually produce, albeit at a low frequency, antibodies that neutralize a whole series of strains,\" said lead author Stephen Harrison of Children\'s Hospital Boston. \"Our goal is to understand how the immune system selects for antibodies and use that information to get better at making a vaccine that will take you in a direction that favors breadth over specificity.\" Last week, researchers in Britain and Switzerland reported in the US journal Science that they had found the first human antibody that can knock out all influenza A viruses. That antibody, FI6, was tested in all 16 subtypes of A flu viruses and consistently worked against the often-changing hemagglutinin, the protein that is on the virus\'s surface.