Western blotting was carried out using standard methods; bmercaptoethanol was used in sample preparation. BLV and HTLV-1 envelope was detected using supernatant from murine hybridoma cell lines expressing monoclonal antibodies raised against recombinant antigen derived from BLV or HTLV-1 envelope, and anti-mouse horseradish peroxidase conjugated secondary antibody at a dilution of 1:10,000 in PBS containing 5% (w/v) marvel and 0.025% Triton X-100.