Use of monoclonal antibodies in an ELISA for the diagnosis of bovine leukaemia virus infection.

An ELISA diagnostic test for detection of bovine leukaemia virus (BLV) infected animals was developed. The test is based on the use of a mixture of monoclonal antibodies (MAbs) against envelope glycoprotein and against viral structural protein p24. The sensitivity and specificity of the test were found to be dependent on the relative proportions of MAbs of the appropriate epitope specificity. Polystyrene microtitre plates, wells or sticks were firstly coated with a mixture of purified MAbs and then non-purified viral antigens were adsorbed from tissue culture fluid obtained from BLV-producing cells. The optimal conditions for adsorption of MAbs and viral antigens as well as for the ELISA procedure were established. The test is more sensitive and cheaper (no need for virus antigen purification) than the routinely used ELISA using purified virus antigens. The assay is highly specific, rapid, practical and could be easily automated. It is suitable for the detection of BLV-antibodies in blood serum or milk in the large-scale screening programs for BLV-infected animals.