Studies on bovine leukosis. VII. Further experience with an ELISA for the detection of antibodies to bovine leukosis virus.

An enzyme linked immunosorbent assay (ELISA) and the agar gel immunodiffusion test with bovine leukosis virus glycoprotein as antigen (AGIDT-BLV gp) were further used to test 633 bovine sera for antibodies to BLV. Both tests detected the same number of sera positive (149) or negative (464) for antibodies. Nine sera were negative in the ELISA but found to be weakly positive (2 sera) or bending the control line (7) in the AGDT-BLV gp. On the other hand 11 sera were scored negative in the AGIDT-BLV gp but were weakly positive (9 sera), positive (1), and strongly positive (1) in the ELISA. Both tests are used routinely in this Institute as they complement each other, specially if sera with low antibody titers are under investigation. It is concluded that ELISA can fully replace radioimmunoassays in the serodiagnosis of enzootic bovine leukosis.