Studies of an Inhibitor of the Two Antibody Immunoassay System

Abstract
A heat labile plasma inhibitor of the two antibody insulin immunoassay system has been investigated by means of paper electrophoresis, ultracentrifugation, and DEAE cellulose anion exchange resin. These studies indicate that the inhibitor does not interfere with the binding of insulin to its specific antibody (first antibody reaction); but that the inhibitor interferes with the reaction of anti-guinea pig serum (rabbit source) with the insulin-anti-insulin soluble complex (second antibody reaction). When plasma samples are appropriately diluted the effect of the inhibitor is minimized.