Preparation of monoclonal antibodies specific for the subclasses of canine IgG.

Canine IgG is composed of four subclasses, which are defined as IgG1, IgG2, IgG3 and IgG4 on the basis of data from fast protein liquid chromatography, and their electrophoretic mobilities and relative concentrations in serum. This paper describes the preparation of mAbs specific for determinants on canine IgG2, IgG3 and IgG4. The mAb specific for IgG2 resulted from a conventional immunisation protocol. The mAb specific for IgG3 was a result of immunisation with IgG3 combined with the suppression of the immune response to IgG1 by passively administered anti-IgG1 antibody. The mAb specific for IgG4 resulted from immunisation with Fab or Fc fragments which were obtained by the cleavage of the IgG4 molecule with papain. The specificity of each mAb was established by using an enzyme-linked immunosorbent assay which showed that all three specific clones recognised a determinant in the Fd region of the canine immunoglobulin molecule.