Abstract
1) The nature of the complement fiixing antigen synthesized in Ehrlich ascites tumor cells after exposure to ED virus are described. Ehrlich CFA is resistant to heating at 56ªC for 30 minutes but is destroyed completely by heating at 65ªC for 30 minutes. Most of the antigenicity was destroyed by the action of trypsin. CFA was separated from the hemagglutinin or egg infectivity of virus particle by adsorption with red cells or centrifugation at 24, 000×g for 90 minutes.
2) This antigen was precipitated with specific immune antiserum. Analysis of the specific precipitates revealed that this antigen is composed of ribonucleoprotein.
24 hours after virus challenge, the amount of RNA in this antigen reached about 2.5% of total RNA of the Ehrlich tumor cell and then Ehrlich tumor cells underwent rapid oncolysis.
3) Differential centrifugation of 0.25M sucrose extract of Ehrlich tumor cells infected with ED virus reveals that some of the complement fixing antigen was situated in the subcellular particle fraction and supernatant fraction, but that most of the antigen was in the fraction precipitated at 120, 000×g for 90 minutes.
4) Electron microscopic changes of Ehrlich ascites tumor cells challenged with ED virus are described. Three types of inclusion bodies were present in the cytoplasm of the tumor cells apparently undergoing degeneration by infection with ED virus. The first type consisted of an ovoid matrix containing homogenously dense population of high density particles with an average diameter of 350Å The second body consisted of multiple round foci which were remarkably homogenous plaques of low to moderate density with their central portions appearing more or less dark. The third type of inclusions is the multilayered shell inclusions containing no particulate bodies.
5) The significance of these inclusion bodies and interaction of RNA between virus and Ehrlich tumor cells are discussed.
