Antibody production in the bullfrog (Rana catesbeiana)

Abstract

Serum antibody was found by radioimmunoelectrophoresis (RIEP) in thirty-one of thirty-five bullfrogs (BF) immunized with one of four protein antigens. Rabbit γ-globulin (RGG) and hen egg albumin were the best antigens, whereas human serum albumin and bovine serum albumin induced a less consistent immune response. Although a IgM to IgG sequence of antibody production usually was detected with RGG as antigen, a similar sequence was infrequent with the other antigens and the initial response was usually a IgG antibody. IgM antibody was detected in the serum for a prolonged interval (>100 days) and precipitating quantities of IgG antibody were found more than 1 year after antigen inoculation. As measured by haemagglutination, the IgM antibody was routinely inactivated by mercaptoethanol (ME) treatment and IgG antibody was frequently inactivated by ME, although it still had antigen binding capacity by RIEP. IgG hemagglutinins, which were resistant to ME treatment, were found in some sera obtained from BF after booster injections of antigen. Immunoelectrophoretic examination of normal or immune BF sera revealed a prominent precipitin line of slow γ-mobility which did not bind ¹³¹I-labelled antigen but did bind ⁵⁹Fe.