Studies on the Serotherapy of Japanese B Encephalitis

Report I: Evaluation of Hyperimmunization, especially that of PVL-combined Immunization

Abstract

For the purpose of producing most potent immune sera, mice and goats were hyperimmunized with the Nakayama strain of Japanese B encephalitis virus. Thereby the effects of PVL combination and partial bleeding upon neutralizing antibody titre were investigated, the results, were:
1) The sera with neutralizing antibodies of high titre were obtained by repeated injections of live and Merzonin-inactivated viruses of Japanese B encephalitis for a long period of time.
2) Combined use of PVL promoted the rise of neutralizing antibody titre, and shortened the term for hyperimmunization.
3) Hyperimmunization appeared to have a definite limit in producing neutralizing antibodies: further injections beyond that limit gave rise to no more rise in titre.
4) Partial bleeding of in followed by appropriate treatments, brings about no descent of the neutralizing antibody titre and reversely ascends the titre, then the combined PVLadministration proved also effective.
5) Normal mice kept near the ones rzceiving immunizing doses of live virus showed the rise of their neutralizing antibody titre following their growth. This rise in titre appears to be due to the inapparent infection.