Immune response in mice infected with the attenuated Japanese encephalitis vaccine strain SA14-14-2.

We characterized protective immune response in mice infected with the attenuated Japanese encephalitis virus (JEV) strain SA(A) derived from the live JE vaccine strain SA14-14-2. In the sera of mice infected with SA(A), antibodies to JEV envelope (E) and non-structural NS1 proteins were detected by Western blot analysis and neutralization, haemagglutination-inhibition (HAI), and complement fixation (CF) antibodies were detected by serological tests. Production of antibody to NS1 protein strongly indicated peripheral growth of SA(A) in mice and its growth induced the immune response. A single immunization with SA(A) significantly protected mice against lethal intracerebral (ic) challenge with the virulent SA(V) strain.