CHARACTERIZATION OF MONOCLONAL ANTIBODIES TO AVIAN LEUKOSIS VIRUSES

Hybridoma cell lines secreting monoclonal antibody (MCA) to avian leukosis virus (ALV) structural proteins p27 and p19 have been established. MCA 6AL20 (IgG1 isotype) reacted with RPL-40, AMV, RAV-2 and Carr-Zilber RSV (CZ-RSV).representing exogenous ALV subgroups A, B and D, respectively, but not the endogenous virus RAV-0 (subgroup E) in an indirect enzyme-linked immunosorbent assay (ELISA). MCA 6AL22 reacted as above and, in addition, reacted with the Prague strain of Rous sarcoma virus (PrC-RSV), subgroup C. Both MCAs im-munoprecipitated p19 from 35S-methionine-labeled RPL-40 or RAV-1,but not RAV-O infected chi-cken embryo fibroblasts (CEF). They can be used to differentiate exogenous from endogenous (RAV-O) infection either in an indirect antibody ELISA or by immunoprecipitation. A third MCA, 6AL42 (IgG2a isotype), reacted with exogenous viruses at an antibody titer up to 1,000-fold higher than with endogenous subgroup E, RAV-O virus in indirect ELISAs. MCA 6AL42 immunoprecipitated p27 and the group-specific antigen precursor protein, pr76, from cells infected with RPL-40, RAV-1 or RAV-O. A double antibody sandwich ELISA, using 6AL42 as the primary binding antibody and conjugated rabbit anti-p27 as the reporter antibody, differentiated between endogenous RAV-O and exogenous p27 antigen in undiluted albumen samples.