[1] Biomed Res Inst Southern Calif, Oceanside, CA 92056 USA
[2] FluGen Inc, Madison, WI 53711 USA
[3] Univ Wisconsin, Influenza Res Inst, Sch Vet Med, Dept Pathobiol Sci, Madison, WI 53711 USA
[4] Univ Tokyo, Inst Med Sci, Int Res Ctr Infect Dis, Dept Microbiol & Immunol,Div Virol, Tokyo 1088639, Japan
[5] Univ Tokyo, Inst Med Sci, Int Res Ctr Infect Dis, Dept Special Pathogens, Tokyo 1088639, Japan