DIALYSIS ASSAY FOR INTRINSIC FACTOR AND ITS ANTIBODY: DEMONSTRATION OF SPECIES SPECIFICITY OF ANTIBODIES TO HUMAN AND HOG INTRINSIC FACTOR.

Abstract

Abstract With the use of an assay system depending on the fact that antibody to intrinsic factor (IF) will block the ability of IF to bind subsequently added vitamin B 12 , 7 species specificity of IF antibody was demonstrated with precipitating antibody produced in rabbits to hog, rat, or human intrinsic factor, and precipitating antibody produced in 2 patients injected with hog IF. In this system, the nonprecipitating antibody present in the serum of patients with pernicious anemia, never treated with hog IF concentrate, was directed against human IF. The nonprecipitating antibody present in the serum of 2 patients with pernicious anemia treated with oral hog IF was directed against human IF; while the nonprecipitating antibody of another such patient was directed against hog IF. These observations support the assumption that circulating autoantibody in patients with pernicious anemia, never treated with hog IF, is directed against autogenous IF. They also support the belief that oral hog IF may on occasion produce circulating antibody, a phenomenon which implies that in certain circumstances there may be absorption of the antigenic determinant from the gastrointestinal tract.