Abstract
A simple assay method was developed to detect for insulin antibody. Small and uniform size of biologically inert polyaminostyrene was combined chemically with insulin through diazo-coupling, and polyazostyrene insulin (PAI) particles were produced under various conditions changing the weight ratios of insulin to polyaminostyrene. 1 g of PAI particles of No.1 to No.4 contained 31.1, 45.2, 46.5 and 49.5 mg of insulin, respectively. The PAI particles with the highest amount of insulin proved to have immunologic reactivity very similar to that of crystalline insulin. As a polyantigen in latex method, the PAI particles were easily linked together with insulin antibody to form visible aggregates in two hours on an immunoplate.
The validity of this latex method was studied by comparing with the results of two conventional assay methods for insulin antibody, i. e. radioelectrophoretic and ethanol precipitation method. 21 insulin treated diabetics in our Diabetes Clinic were selected and their insulin antibody titers in sera were measured by the above three methods. The subjects having insulin binding capacities over 25 u./l. serum by electrophoretic method and insulin antibody titers over 65% by ethanol precipitation method showed positive PAI agglutination test.
But the subjects having insulin binding capacities of 10 u./l. serum showed either positive or negative in PAI test.
It was shown that this PAI agglutination test was simple and accurate method and had practical value on the estimation of insulin antibody in sera of insulin treated diabetics.
