Differences in haemagglutination activity and electrophoretic mobility of E protein between the parent SA14 and attenuated vaccine SA14-14-2 strains of Japanese encephalitis virus.

E protein characteristics of the attenuated Japanese encephalitis (JE) virus strain SA(A) derived from the live vaccine strain SA14-14-2 were compared with those of the virulent strain SA(V). SA(A) showed lower haemagglutination (HA) activity with broader optimum pH range of HA reaction than SA(V), and the E protein of SA(A) had slower electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) than that of SA(V). These properties of SA(A) E protein appear to be caused by eight amino acid changes found in the E protein coding region of the SA(A) virus genome.