Studies of mouse polyoma virus infection. 1. Procedures for quantitation and detection of virus

THREE PROCEDURES HAVE BEEN COMPARED FOR USEFULNESS IN TITRATION AND DETECTION OF POLYOMA VIRUS: production of cytopathic effect (CPE) in mouse embryo tissue culture, production of HI antibody after inoculation into weanling mice (MAP test), and production of tumors in suckling hamsters during a 3 to 5 week observation period. The tissue culture and mouse antibody production tests were generally comparable in sensitivity, reproducibility, and time required to obtain results. Titration by tumor production in suckling hamsters was not suitable for quantitation because of marked variation in susceptibility among animals. Virus was detected in tissues of normal mice from spontaneously infected colonies by either production of CPE in mouse embryo tissue culture or by the MAP test; virus was found in organs of 15 (58 per cent) of 26 mice with antibody, and 2 (8 per cent) of 24 mice without antibody.