Complement-fixation test for feline leukemia and sarcoma viruses (the COCAL test)

Abstract

A feline leukemia and sarcoma group-specific complement-fixation (CF) test has been developed, analogous to the COFAL test for the avian leukosis viruses and the COMUL test for the murine leukemia viruses. CF viral antibodies used in this test were prepared by immunizing rabbits with ether-disrupted feline leukemia virus and by the induction of fibrosarcoma in beagle dogs with the GA strain of the feline fibrosarcoma virus. The dog CF antibodies contained viral envelope antibodies as well as antibodies to the ether-resistant, nonsedimentable antigens (gs antigen) of the virus. A tissue culture CF viral antigen induction test was devised for the detection and assay of infectious virus and viral-neutralizing antibodies. The test was useful and sensitive for the routine detection and assay of various field strains of feline leukemia virus. High titers of infectious virus and/or viral antigen were found in various preparations from cats with lymphosarcoma and cultures of feline, canine, and human cells inoculated with the virus. The presence in feline sarcoma virus stocks of 100- to 1000-fold excess of noncytopathogenic feline leukemia virus was detected. The CF test for feline leukemia and sarcoma viruses (the COCAL test), may be useful as a routine laboratory tool in the studies of the natural occurrence and transmission of feline leukemia and sarcoma viruses in cats and other species.