日本人の母親とその胎児における日本腦炎, セントルイス脳炎並びに西部型馬腦炎等の各ウイルスに対する中和抗体の比較

Abstract

It is of interest both clinically and immunogically to investigate the first appearance of antibody in foetus during the pregnant period. From this view point 65 samples of maternal blood, 8 samples of foetal cord blood, 3 samples of heart blood and the emulsions of the various organs such as liver (32 samples), spleen (8 samples), muscles (7 samples) and whole embryo tissues except liver (36 samples) which had been collected in each pregnant month were tested by neutralization test against Japanese encephalitis virus with the following results.1) The titer of neutralizing antibody of umbrical cord blood was generally a little higher than those of venal blood specimen of the mother. The heart blood of 7-9 month old foetus showed approximately the same or a little lower titer than those.2) The titer of neutralizing antibody of the liver emulsion of embryo aged two months was found lower than those of maternal blood. On the third month of pregnancy a certain percentages of the embryonic samples began to show higher titer. After the fourth month almost all the embryonic samples demonstrated high neutralizing agent.3) As for the embryonic tissues except spleens, muscles and liver, the emulsion of them failed to show any relation with maternal blood specimen as observed in the case of liver emulsion mentioned above.To discuss the specificity of the neutralizing substance mentioned so far, maternal blood specimen (10 samples), embryonic liver emulsion (5 samples), emulsion of whole embryonic tissues except liver (1 samples) and umbrical cord blood (4 samples) were examined by the neutralization test against Japanese encephalitis, St. Louis encephalitis and western equine encephalitis viruses.Except a few exceptions (3 samples of liver emulsion and one sample of the whole tissue emulsion except liver), all the rest of the tested samples were negative against St. Louis encephalitis virus. The four specimens positive aginat St. Louis encephalitis virus were further tested against Japanese encephalitis virus. They resulted in positive of more than 1, 000 neutralization index. Two of those positive samples were also positive against western equine encephalitis virus. Before going to conclusion it should be kept in mind that there has been no confirmed information on the existence of St. Louis encephalitis in Japan. The positive neuttalization test may be due to the cross reaction between both Japanese and St. Louis encephalitis viruses though it is too much to admit all the neutralizing substance as specific.One sample of maternal blood, one sample of cord blood and two liver emulsions were positive against western equine encephalitis, but all the rest of the specimens tested were negative. The four western equine encephalitis positive samples were also positive against Japanese encephalitis virus with over 1, 000 neutralization index. Of the four positive samples, two were also positive against St. Louis encephalitis virus. From foregoing results it may be concluded that some non-specific virulicidal substance might exist in the tested samples both organ emulsion and blood and that the neutralizing antibody against Japanese encephalitis virus could be detected in organ emusions of foetus aged four month higher than those in its mother's blood.