The tissue culture cells, dog kidney, HeLa-S3 and PS cells infected with measles virus (Edmonston strain) were studied with the staining methods of Feulgen reaction, methylgreen pyronine and acridine orange, and with RNase digetion test. The results were as follows.
1) The CPE of the cultured cells inoculating measles virus was observed as many authors reported to be consisted of the multinucleated giants cells, cytoplasmic inclusion bodies, intranuclear inclusion bodies and spindel like cells,
2) The cytoplasmic inclusion bodies showed Feulgen negative, red staining with methylgreen pyronine, pale blue to pale green with acridine orange and RNase resistent. As a result presumably they had RNA, but did not always neglect the presence of acid mucopolysacchrides.
3) The intranuclear inclusion bodies had no nucleic acids because no fluorescence was detected corresponding to most of them.
4) With acridine orange staining, the nucleoli of the infected cells became enlarged and showed brilliant red fluorescence, and there was an increase in the size and yellow fluorescence in the nuclei. Cytoplasmic red fluorescence also increased. It seemed to be an accerated metabolism of nucleic acids in the infected cells.
5) The small brilliant red fluorescent particles with halo in the cytoplasm were basophylic when restained with hematoxylin eosin. Therefore they were not identified with the cytoplasmic inclusion bodies.
6) It was not determined whether the cytoplasmic inclusion bodies and intranuclear inclusion bodies were the sites of the synthesis of viral component or not with the methods of nucleic acid staining. But they presumably related to the synthesis of viral components.