Abstract
Infection of CRFK feline kidney cells with Aleutian disease vurus leads to production of virus-induced antigen(s) in the nucleus which could be demonstrated by the fluorescent-antibody technique. The number of fluorescent nuclei was lineraly dependent on the dilution of the inoculum, but rarely exceeded 20% of the cells. Aleutian disease nuclear antigen was only transiently detectable. The virus-induced antigen was detected after infection of cells of several divergent species; however, the CRFK line of feline kidney cells was the most susceptible. Inhibitor studies indicated that deoxyribonucleic acid synthesis, ribonucleic acid synthesis, and protein synthesis were required for viral antigen production. Cell growth was also a requirement for synthesis of viral antigen, An in situ radioimmune assay was used to measure binding of 125I-labeled mink anti-Aleutian disease virus to infected cells and competition with unlabeled sera. The system is suitable for quantitation of infectivity.