INDUCTION OF ARGINASE ACTIVITY WITH THE SHOPE PAPILLOMA VIRUS IN TISSUE CULTURE CELLS FROM AN ARGININEMIC PATIENT

Inoculation of the Shope virus in tissue cultures of human fibroblasts from a patient with a deficiency of the enzyme arginase results in an induction of arginase activity, apparently virus coded.

CHANGE IN THE STRUCTURE OF SHOPE PAPILLOMA VIRUS-INDUCED ARGINASE ASSOCIATED WITH MUTATION OF THE VIRUS

The change in the state of the virus-induced enzyme associated with a mutation in the virus provides additional evidence that the enzyme is synthesized from virus rather than rabbit genetic information. This change in structure results in differences in stability of polymerization, degree of optical rotary dispersion (ORD) specific rotation, change in elution characteristics from carboxymethyl cellulose, and a reduction in specific activity of the arginase. Liver arginase differs markedly in ORD characteristics from the virus-induced enzyme. In contrast to the virus-induced enzyme, it showed no negative Cotton effect at 233 nm until it was activated with manganese. Manganese had no influence on the ORD spectrum of virus-induced arginase. In addition, liver arginase is denatured by 4 M urea, while the virus-induced enzyme requires 10 M urea for denaturation.

IN VITRO CULTIVATION AND IMMUNOFLUORESCENT STUDIES OF TRANSPLANTABLE CARCINOMAS Vx2 AND Vx7

The Vx2 and Vx7 rabbit carcinomas, both of Shope papilloma derivation, were cultivated in vitro and studied for immunofluorescence indicative of the presence of viral antigen. The cultured Vx7 cells were characteristically pleomorphic, round or polygonal cells, and immunofluorescence was demonstrable in 5–20% of them as counted on cover slip cultures after exposure to rabbit sera containing anti-Shope papilloma virus antibody. The Vx2 cells in contrast to this were of almost uniform size and character, small and approximately round, and the specific fluorescence was found in less than 0.1% of the total number. These findings indicate that some antigenic derivation from the Shope papilloma virus is still persisting at least in some fractions of the cells, not only of Vx7 tumors but also of the Vx2 tumors, even after maintenance of the growths by transplantation for more than 20 yr. During the course of the study, two lines of the Vx7 were kept continually growing while the culture of Vx2 was discontinued at its tenth passage after an accident due to mechanical failure of the incubator. The neoplastic capacity of the Vx7 cells cultured in vitro was demonstrated by implanting these intradermally on the ears of domestic rabbits. The result was destructive carcinomas of the Vx7 sort.