Aspects of the secondary antibody response to ox insulin in the Hartley guinea-pig; the use of chemically modified ox insulin to delineate the antigenic determinants of ox insulin.

The use of a quinea-pig model to study the immunogenicity of the insulin molecule is presented. The Hartley guinea-pig has been shown consistently to form antibody to ox insulin, when given in a water-in-oil emulsion containing pertussis vaccine as adjuvant. After log transformation of standardized antibody titres to iodo-ox insulin, a valid statistical comparison of the antibody response to different ox insulin preparations could be made. Antibody cross-reacting with ox insulin, but not iodo-ox insulin, was also detected. The quantity of one type of antibody was complementary to the other, an observation compatible with determinant competition having occurred during the immune response. From the results of cross-reactivity experiments using N-triacylated ox insulins and human insulin, it was shown that antibody cross-reacting with iodo-ox insulin had most probably been produced to a localized area of the molecule.