A critical comparison of the virus neutralizaiton, radioimmunoprecipitation and immunodiffusion tests for the serological diagnosis of BLV infection.

Several serological tests are available for the detection of antibodies to BLV. Thus far, only the virus neutralization antibody (VNA) test, the immunofluorescence test, and the immunodiffusion test with the major internal virion protein have been critically evaluated as diagnostic methods for the identification of BLV-infected cattle. Of these tests, the VNA test is the most sensitive and specific. Therefore, in the present study the VNA test has been applied to evaluate the reliability of the radioimmunoassay for BLV p25 (RIAp25) and of the immunodiffusion test with BLV-associated glycoprotein antigen (IDgp). The results show a very close agreement between the RIAp25, and the VNA test. The IDgp test is less sensitive than the RIAp25, particularly for the detection of BLV antibodies in early stages of infection. The RIAp25 is more rapid than the VNA test and does not require tissue culture techniques. Thus, the RIAp25 seems to be the most practical and sensitive available method for the serolgical diagnosis of BLV infection in cattle.