Immunological Specificity of Sulfonamide Azoproteins

Abstract

Discussion and Summary of Results

1. In all 3 types of experiment, skin tests, anaphylaxis, and precipitin reactions, the sulfanila-mide and sulfapyridine azoproteins produced heterologous antibodies for each other although the homologous reactions were always stronger. The animals injected with sulfapyridine azoprotein were more reactive to sulfanilamide azoprotein than vice versa. Therefore it might be predicted clinically that patients hypersensitive to sulfanilamide could tolerate sulfapyridine better than those patients sensitive to sulfapyridine could tolerate sulfanilamide. 2. Sodium sulfathiazole azoprotein did not form a precipitate with sulfanilamide or sulfapyridine azoprotein antiserums. This suggests the thiazole may be too far removed from the fundamental sulfanilamide structure to participate clinically in heterologous reactions. 3. The highest precipitin titer found was that of sulfanilic acid azoprotein antigen and sulfanilamide azoprotein antiserum. It seems difficult to account for this as a minor group phenomenon. Is it possible that the sulfanilamide in vivo is changed to a structure like sulfanilic acid which then acts as a precipitinogen? 4. There was no evidence that the simple chemicals uncombined with protein could serve either as immunizing or testing antigens. However, 2% sodium sulfapyridine inhibited sulfanilamide and sulfapyridine azoprotein precipitins without affecting the precipitins for beef serum.