Induction of neutralizing antibodies to transmissible gastroenteritis virus by anti-idiotypic antibodies

The potential of anti-idiotypic antibodies (anti-ids) as immunogens against transmissible gastroenteritis virus (TGEV) was tested in a heterologous system. A month-old pig was immunized with a neutralizing murine monoclonal antibody (MAb, 5A5) of the IgG(2a) isotype, specific for the E2 glycoprotein of TGEV. The anti-ids were isolated from the serum of the immunized pig by affinity chromatography, initially on a 5A5-Sepharose column, followed by repeated adsorption on a mouse IgG(2a) column. The swine anti-ids thus obtained bound to the MAb 5A5 (the idiotype), but not to MAbs of the same isotype IgG(2a) but of different idiotypes. The anti-ids also inhibited the binding of 5A5 to TGEV in a concentration-dependent manner. Mice immunized with the anti-ids produced antibodies to TGEV. These antibodies, neutralized TGEV in vitro and inhibited the binding of 5A5 to TGEV.