To examine the therapeutic effect of the hyperimmune sera on the mice infected with Japanese B encephalitis virus as well as the mode of their application, the hyperimmune sera of mice and goats were given by the different routes and intervals.
The results were as follows:-
1) The hyperimmune sera have therapeutic and preventive virtues in proportion to their neutralizing antibody contents, and are more effective when administered convergently before or after the challenge of the virus.
2) Hyperimmune sera administered into peritoneal cavity of mice shortly after the intraperitoneal challenge lowers the fatality rate.
The sera administered intracerebraly even 24 or 48 hours after the challenge havecaused the marked fall of mortality. And also the serum administered after 72 hours was able to reduce the rate though a little.
3) When hyperimmune sera are inoculated intraperitoneally and intracerebraly at the same time or intracerebraly once and again, the mortality rate is higher on occasions than when only once inoculated intracerebraly.
4) When the virus is inoculated intracerebraly, the hyperimmune serum proved effective only when it was administered early enough into the brain.
5) The homologous hyperimmune sera involve less ill effects and are Xmore efficacious than the heterologous sera.
6) The average death-days of the mice challenged by the intracerebral route are lengthened in every case by serum injection, but the prolongation did not always follow intraperitoneally challenged.

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Protective and therapeutic effects of purified serum fractions on the mice infected with Japanese B encephalitis virus were studied to obtain the following results.
1) Both SII+III-w and PII+m-w fractions of goat's immune serum which has high neutralizing titre proved highly effective for the prevention and treatment.
2) Gammaglobulin fraction of human adult's plasma is also effective if it had high antibody titre.
3) Gammaglobulin fraction of the adult's sera seems to be useful for practical purpose because the homologous sera had proved to be more harmless and more effective the treatment than the heterologous sera.
4) It is recommended to take prophylactic measures by administering either immune sera or γ-globulin of high potency at the peak of an epidemic of Japanese B encephalitis, based on the fact that, in mice, a tare increase in resistance can protect the mice from attack.
5) Treatment of Japanese B encephalitis can be achieved only by the early inhibition of the intracerebral propagation of the virus.
For this purpose, much are left to be investigated in the serotherapy, none the less, the serotherapy appears to be a very promising method.

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It has been described, that Newcastle disease virus is able to agglutinate red blood cells (RBC) derived from various kinds of animals. The agglutinability, however, is recognized to be different according to the kind of mammalia. Although hemoagglutination of Newcastle disease virus is principally taken place with the same mechanism as that of influenza virus, the behaviour of the former seems to be slightly different from the latter; for instance, the elution from RBC may happen much easily in the phemomen with Newcastle disease virus, even at 0°. It is, therefore, considered that non-hemoagglutination in the tube test does not always mean lack of adsorbing ability of RBC.
The auther studied on the adsorption and elution of Newcastle disease virus in hemoagglutination and hemoadsorpiton test, using RBC of various kinds of animals, . particularly of chicken and horse RBC ; the former is most susceptible and the latter unsusceptible to hemoagglutination by Newcastle disease virus isolated in Japan. In the study, the existence of receptors in horse RBC similar to that of chicken RBC was proved. Results are summarized as follows:
1) When treated with KIO₄, virus lost the eluting ability from RBC, but no influence on the agglutinating ability was observed; therefore, the hemoagglutination and adsorption successful with horse RBC, but titre of those tests w ere of low grade.
2) When treated with RDE derived from Vibrio cholera culture, RBC losts the adsorbing ability. Horse RBC showed the behavior similar to that of chicken RBC in the absorption test.
3) The hemoadsorption test was recognized to be established by using Newcastle diseases virus and chicken embryonic monolayer system. It was clear, that antigenic agent participating in this phenomen has to be closely related to hemoagglutinating antigen.
4) RBC, both avian and mammalian, were similary well adsorbed to monolayer cells infected. RBC treaed with RDE were not adsorbed.
From the results mentioned above, it seems to be evident that horse RBC, unsusceptibleto agglutination by Newcastle disease virus, has receptors susceptible to RDE andis equivalent to chicken cells in absorbability. Negative hemagglutination of horse RBC in the tube test may be chiefly due to the elution taken place in the process of RBC sedimentation.

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