Finally, we report the development of a large panel of human mAbs induced by pandemic H1N1 infection. Prophylactic therapy with polyclonal or mAbs has successfully been used for RSV, rabies, Hepatitis A and B, and varicella. In the case of influenza, mAbs have been shown to provide prophylactic or therapeutic protection in mice and other animal models (Reuman et al., 1983; Sweet et al., 1987; Palladino et al., 1995; Renegar et al., 2004) . Passive transfer of maternal antibodies in humans has also been shown to confer protection (Puck et al., 1980) . Several of the antibodies we isolated have broad neutralization capacity in vitro against divergent influenza strains and show potent prophylactic and therapeutic activity when used to treat mice that were lethally infected with influenza. These antibodies could provide much needed pandemic therapeutics to treat severe cases of influenza and to protect high-risk populations.