Haptenic antibody induced by N-phthaloylated ox insulin in the Hartley guinea-pig.

Female Hartley guinea-pigs were immunized with N-phthaloylated ox insulin (96% NA1,NB1,NB29-triphthaloyl ox insulin) using H. pertussis as adjuvant. Haptenic antibody, which was found in antisera taken 20 days after secondary immunization, was assessed for cross-reaction with a series of N-acylated ox insulins. Cross-reaction readily occurred between haptenic antibody and the partial hapten-bearing antigens, NA1-monophthaloyl and NB1-monophthaloyl ox insulins. The immunochemical data suggested that the NA1-glycyl hapten and the NB1-phenylalanyl hapten were both acting as immune determinants for B-lymphocytes, and the determinant competition was taking place between contralateral facets of the principal immunogen, NA1,NB1,NB29-triphthaloyl ox insulin. The data was also consistent with the view that the overall tertiary structure of N-acylated insulins may be very similar to that of their native insulin, the addition of hapten groups having produced only localized areas of structural perturbation.