The present invention provides antibodies that neutralize flavivirus and methods of use thereof. These antibodies are derived from mAb1 1 which recognizes West Nile virus E protein and is cross-reactive with members of the flavivirus family, including Denge virus. The antibodies of the present invention prevent antibody-dependent enhancement of a viral infection by having a modified Fc region that does not bind to the Fcy receptor. The invented antibody is used to treat flaviviral infections and symptoms thereof.
