Biken-CAM and Sugiyama-3 vaccines developed in Japan were studied in a field trial involving about 1000 seronegative children, 8 months to 6 years of age, along with Schwarz, Leningrad-16 and ESC vaccines which had been extensively tested by other workers.
All vaccines produced a satisfactory serologic response except Biken-CAM vaccine which failed to induce antiboby in one-fifth of vaccinated children. This unsatisfactory result of Biken-CAM vaccine is obviously due to an insufficient dose of virus as other data indicate. The vaccines induced clinical reactions such as pyrexia and rash, but no side reactions of any consequence. The overall assessment of the clinical data seem to indicate that in clinical reactions ESC vaccine is mildest, Schwarz and Leningrad-16 vaccines are less mild, and Biken-CAM and Sugiyama-3 vaccines still somewhat less mild. The two Japanese vaccines, however, are obviously much more attenuated as compared with those licensed live vaccines of Japan, and seem to belong to a group of further attenuated vaccines which can be administered without gamma globulin or prior inoculation of killed vaccine.

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The intratypic serodifferentiation test of type 3 polioviruses was carried out with the modified Wecker technique using anti-Sabin 3 rabbit sera. Thirty-four vaccine-related and 28 nonvaccine-related strains were examined. Of the 34 vaccine-related strains, 30 were classified as vaccine-like, 3 as intermediate, and one as nonvaccine-like. Out of 28 wild strains tested, 12 were classified as nonvaccine-like, 7 as intermediate, and 9 as vaccine-like.
These results showed that with the modified Wecker technique, vaccinerelated virus could be classified as vaccine-like, whereas some of the wild type 3 poliovirus isolated in Japan were indistinguishable antigenically from the Sabin type 3 vaccine virus. For the more conclusive differentiation of type 3 polio strains, it was needed to carry out comparative studies of these strains by the McBride and modified Wecker techniques.

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Poliovirus strains, both wild and Sabin-vaccine-derived, were studied by neutralization kinetic with antisera against the vaccine virus, and the results were compared with those obtained by the modified Wecker test. With type 1 and type 2 wild strains isolated in Japan, eleven type 1 strains and five type 2 strains were classified as heterologous to the vaccine strains in complete agreement by the two methods. One type 2 strain was classified as heterologous by the McBride test and intermediate by the modified Wecker test. As regards type 3 poliovirus strains, 17 wild strains were classified as heterologous by the McBride test, but the modified Wecker test discriminated only 9 as heterologous, while 4 other strains were classified as intermediate or homologous to the type 3 vaccine virus. Most of the poliovirus strains which were assumed as vaccine-related were classified as homologous or intermediate by the two methods, but some were classified as heterologous by the modified Wecker test and/or McBride tests. Detailed investigation of these strains by the reciprocal kinetic neutralization tests indicated that most of them were considered as nonvaccine-related. One of type 2 isolates and two of type 3 isolates from vaccinees in the field trial of 1961 could not be classified definitely. The data indicated that the McBride test is in some cases more suitable for the serological differentiation of poliovirus strains obtained in relation with Sabin vaccine feeding. It will be wise not to depend upon only one method in the serological differentiation of poliovirus strains, but better to use the two methods, as well as the reciprocal testing, if necessary.

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An enterotropic avirulent Newcastle disease virus (NDV-Ishii) which was administered by the oral route in a dose of about 10⁵-10⁸ TCD₅₀/chick caused alimentary tract infection in 4 week old chickens, which excreted NDV-Ishii in feces from 3 to 7 days after the first feeding. Indirect fluorescent antibody microphotograph of sections of the small intestine revealed that a sort of surface infection was established by the oral administration of enterotropic NDV. But the virus was scarcely recovered from feces after the second feeding 4 to 6 weeks later and the neutralizing activity of fecal extracts, probably coproantibody, was demonstrated a few weeks after the virus feeding. Bursectomy plus γ ray irradiation (650 r) after hatching exerted a profound influence on humoral immunity, namely, suppression of HI antibody production in serum, and at the same time the development of local immunity of the alimentary tract was disturbed. Those chickens excreted the virus even after its second administration. On the other hand, thymectomy plus γ ray irradiation or γ ray irradiation alone had no suppressive effect on establish-ment of the alimentary tract resistance to reinfection. Therefore it is concluded that the local immunity of the alimentary tract of chickens against refeeding of the enterotropic NDV depends largely on humoral immunity governed by the bursa-dependent lymphoid system, and probably on IgA antibody which is produced locally by lymphoid cells of the lamina propria.

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Serial passage of Japanese encephalitis (JE) virus, strain 281801 from heron blood, in L mouse fibroblastic cell cultures produces a variant virus with enhanced cytopathic effects (CPE) for L cells. Similarly serial passage of infected Lass human epithelial cells and virus in carrier cultures of strain M5/596 from mosquitoes yielded a variant virus with increased CPE for Lass, though not for HeLa human epithelial cells. Such results did not always occur however, because in another series of carrier cultures, Lass cells gained the upper hand and virus disapeared after 11 passages and 257 days. Although unadapted JE virus produced cytopathic effects in cultures of Lass cells, this CPE involved less than 10% of cells and was quickly repaired by migrating healthy cells even though it correlated with production of infectious virus into the cultural fluid. Titers of the L cell variant virus were higher in L cell cultures than in weanling mice inoculated intracranially, but were similar for the Lass cell variant in mice and in Lass cell cultures based on CPE or infectivity.

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Indirect fluorescent antibody tests were used to localize effective antigens at the sites of their formation in adult flukes, metacercariae and eggs of Clonorchis sinensis. Sera from rabbits experimentally immunized against various elements of the flukes and from experimentally infected rabbits as well as sera from human cases of clonorchiasis were used. Specific fluorescence was demonstrated in the cuticle, oral and ventral sucker, pharynx, digestive caecum and its contents, testes, seminal receptacle and ovary of the adult fluke. Weak specific fluorescence was found in metacercariae and in the walls of their cysts. Clonorchis eggs showed no reaction. No cross reactions were detected with sera from human cases of schistosomiasis, ascariasis, trichuriasis, hook-worm disease or syphilis. It is concluded that the adult fluke of Clonorchis is the main source of antigens that effectively stimulate antibody production in the definitive host, and that the maturing metacercariae are responsible for the initial antigenic stimulation during the first few weeks.

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