Production and characterization of monoclonal bovine immunoglobulins G1, G2 and M from bovine × murine hybridomas

Three bovine × murine hybridomas, which secrete bovine IgG₁, IgG₂ and IgM, respectively, were derived by the fusion of normal bovine B lymphocytes to the murine cell line SP-2/0. The hybridomas were initially selected by testing the culture supernatant of individual clones with rabbit anti-bovine light chain antibody. The bovine nature of Ig secreted by the bovine × murine hybridomas was confirmed by the ability of bovine serum but not murine serum to inhibit specific adsorption by murine anti-bovine Ig coupled to Sepharose 4B and the inability of sheep anti-mouse Ig (all isotypes) to bind biosynthetically labelled Ig from the respective bovine × murine hybridomas or to react with bovine × murine hybridoma Ig in Ouchterlony analysis. The isotype of the bovine Ig produced by each hybridoma was determined by cRIA using bovine Ig isotype-specific murine mcab, Ouchterlony analysis with guinea pig anti-bovine Ig isotypes and molecular weight analysis of unreduced and reduced affinity purified Ig from the respective bovine × murine hybridomas. Even though the hybridomas in this study showed chromosome loss, they have continued to secrete bovine Ig in culture for over 16 months, indicating that it is possible to isolate and stabilize interspecific hybridomas retaining the chromosome, or at least the genes, encoding an Ig.These hybridomas will provide monoclonal bovine Ig for; 1) serological standards, 2) production of polyclonal and monoclonal antisera to bovine Ig isotypes, 3) sequencing studies, 4) serological and structural studies of bovine Ig classes and subclasses, and messenger RNA for the production of cDNA probes for the cloning of bovine Ig genes and for determining the organization of Ig genes in the bovine genome.