Abstract
The insulin binding substance and serum insulin observed in a newborn infant and her mother not previously treated with insulin, were studied with immunological methods.
The insulin binding substance in those patients showed quite similar characteristics to that of insulin treated patients in sephadex chromatography, agarose electrophoresis and radioimmunoelectrophoresis.
However, further studies showed that the substance was pure IgG antibody with K-chain as light chain and stronger affinity to human and porcine insulin as compared to bovine insulin in contrast to the antibody of the insulin treated patients. The peripheral lymphocytes of the mother produced anti-insulin antibody in in vitro tissue culture.
The serum insulin of the patients showed no detectable abnormality with dilution test and insulin degradation test with insulin specific peptidase.
It is concluded that the insulin binding substance in those patients is a insulin antibody produced not by exogenous insulin but probably against endogenous insulin by denaturation of endogenous insulin or changes of antibody producing mechanism.
