A highly sensitive enzyme immunoassay of anti-insulin antibodies in guinea pig serum.
A highly sensitive enzyme immunoassay of anti-insulin antibodies in guinea pig serum is described. Guinea pig anti-insulin serum was diluted to various extents with nonspecific guinea pig serum and incubated with insulin. After incubation, free insulin was separated from insulin-anti-insulin antibody complex by treatment with dextran-charcoal. Anti-insulin antibodies in the complex were dissociated from insulin by incubation with 0.23 M HCl and inactivated. The amount of dissociated insulin was measured by sandwich enzyme immunoassay using anti-insulin IgG-coated polystyrene balls and affinity-purified anti-insulin Fab'-horseradish peroxidase conjugate. The detection limit of anti-insulin antibodies in guinea pig serum was 6.7 pg/assay or 150 ng/liter of serum. The present enzyme immunoassay was 10,000-fold more sensitive than the previously described enzyme immunoassay, in which insulin-coated polystyrene balls were incubated with diluted guinea pig anti-insulin serum and subsequently with rabbit (anti-guinea pig IgG) Fab'-horseradish peroxidase conjugate.
D000818:Animals; D000906:Antibodies / Q000032:analysis*; D006168:Guinea Pigs; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera / Q000032:analysis; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000032:analysis; D007328:Insulin / Q000276:immunology*
D000906:Antibodies; D007106:Immune Sera; D007074:Immunoglobulin G; D007328:Insulin