Assay of partially neutralized guinea pig anti-insulin serum.

Abstract

Constant volumes of guinea pig anti-insulin serum (GPAIS) were first incubated for 1 hr at 36 C with variable amounts of bovine, pork, human, rat and cod insulins, residual reactive insulin antibodies being then assayed under varied experimental conditions using mixtures of unlabeled and 131I-labeled bovine insulin. After partial neutralization with smaller amounts of the mammalian insulins, binding of bovine insulin by residual antibodies could be linearly related to the amount of preincubated insulin. Regression coefficients for the mammalian species of preincubated insulin were the same under comparable conditions of assay, but cod insulin reacted only weakly with the antibodies to bovine insulin. After complete neutralization with larger amounts of the mammalian insulins, GPAIS was still able to react with bovine insulin, which appeared to displace preincubated heterologous (cod > rat > human > pork) more than the homologous bovine insulin. Results are discussed in relation to a similar method used to...