Studies on nonprecipitating insulin antibody. Radioimmunoassay of insulin binding capacity and its relationship to insulin neutralizing activity and ability to evoke cutaneous anaphylactic reaction.

Skom and Talmage have demonstrated a non-precipitating antibody against insulin in the sera of insulin-treated diabetics. But their method of determining the antibody is not quantitative. In the present study, a titration of the insulin binding activity of anti-insulin was performed more quantitatively using 1311-labeled insulin and antiguinea pig r-globulin rabbit sera under the condition of insulin excess.Moreover, the insulin binding act ivity of anti-insulin was corr elated with its insulin neutralizing activity and also with its ability to evoke a cutaneous anaphylactic· reaction. A considerably good correlation was observed between the insulin neutralizing activity and insulin binding activity. On the other hand, between the insulin binding activity and the ability to evoke cutaneous anaphylactic reaction was only a poor correlation observed.