Produce Japanese Encephalitis standard antiserum of strain Nakayama for vaccine quality control

Japanese Encephalitis vaccine has contributed to repel Japanese Encephalitis in young children in the national vaccination campaign. To qualitatively evaluate the protective efficiency of Japanese Encephalitis vaccine, a standard antiserum used as a positive control was performed in parallel with testing samples. A study was organized at National Institute for Control of Vaccines and Biologicals (NICVB) as following. Anti-sera were produced by 2-dose-injection of national standard vaccine to 28-day-old white mice, weighing 11- 13g. After blood collection and serum separation, the PRNT50 neutralizing antibody potency was evaluated in parallel with international standard antisera from NIBSC and antisera from Vabiotech manufacturer. Antiserum lot 0118 was produced with a neutralizing antibody potency PRNT50 of 1.74 to ensure criteria of a positive control standard for performing Japanese Encephalitis vaccine potency test.