(a) nAbs D8, F10 and A66 all neutralized H5-TH04, H1-SC1918, H1-PR34, H1-WSN33, H2-JP57, H6-NY98 and H11-MP74 (strains described below) pseudotyped viruses. (b) Microneutralization assay. Neutralization titers (0.1 mg ml-1 Ab stock solution) of nAb F10 against two wild-type H5N1, three H1N1, one H2N2, one H6N1, one H6N2, one H8N4, two H9N2 and one H3N2 virus. 80R is the negative control. Vertical bars and whiskers represent the lowest and highest neutralization titer (2χ, values of χ are shown on the y-axis) of 2-3 independent experiments. (c-d) Prophylactic efficacy against two H1N1 strains in mice. % survival of mice treated with anti-H5 nAbs or control mAb are shown before lethal challenge by i.n. inoculation with (c) H1-WSN33 or (d) H1-PR34 viruses. Complete viral strain designations are: H1-OH83 (A/Ohio/83 (H1N1)), H1-PR34 (A/Puerto Rico/8/34 (H1N1)), H1-SC1918 ((A/South Carolina/1/1918 (H1N1)), H1-WSN33 (A/WSN/1933 (H1N1)), H2-AA60 (A/Ann Arbor/6/60 (H2N2)), H2-JP57 (A/Japan/305/57(H2N2)), H3-SY97 (A/Sydney/5/97(H3N2)), H6-HK99 (A/quail/Hong Kong/1721-30/99(H6N1)), H6-NY98 (A/chicken/New York/14677-13/1998 (H6N2)), H7-FP34 (A/FPV/Rostock/34 (H 7 N 1)), H 8-ON68 (A/turkey/Ontario/6118/68), H9-HK(G9)97 (A/chicken/HongKong/G9/97 (H9N2)), H9-HK99 (A/HongKong/1073/99 (H9N2)), H11-MP74 (A/duck/memphis/546/74 (H11N9)).