Studies on Chick Embryo Vaccines Against Japanese B Encephalitis

[摘要] The preparation of formolized vaccines from chick embryo tissue infected with Japanese B encephalitis virus has been described.The chick embryo vaccines showed much lower immunogenic power than mouse brain vaccines when they were submitted to the mouse potency test required by the National Institute of Health.The apparently inferior antigenic qualities of chick embryo preparations seemed to be related to the conditions set forth by the “NIH test,” viz., to the fact that both vaccination and challenge inoculation of mice were done by the same route.When mice were vaccinated by intraäbdominal route and challenged by intravenous route, the immunogenic power of vaccines prepared from chick embryo tissue was found to be comparable to that of mouse brain vaccines.One out of four individuals vaccinated with mouse brain vaccine showed the presence of specific neutralizing antibodies in her serum drawn after vaccination, while one out of three individuals vaccinated with chick embryo preparation developed neutralizing antibodies. A fourth individual vaccinated with chick embryo vaccine developed neutralizing antibodies but since this individual had received an injection of mouse brain vaccine six months previously, an anamnestic response could not be ruled out.The findings are discussed and the conclusion is reached that in view of the potential danger involved in vaccinating humans with preparations derived from nervous tissue, chick embryo vaccines should be studied for the purpose of replacing mouse brain vaccines.

[学科分类] 生物科学（综合）