A method of enhancing a mammalian immune response to a virus is disclosed. The method comprises administering a composition comprising an effective amount of epinecidin (Epi)-1the virus to a mammal, wherein the virus has envelope proteinis infectious to the mammal. In this technique, Epi-1Japanese encephalitis virus (JEV) were mixedinjected into mice. The mice were infected with JEV 14 days later,all mice survived. This technology has also been verified in the preparation of vaccines for foot-and-mouth disease virusnervous necrosis virus.