Specific suppression of antigen-antibody reactions by a dialysate from Dermatophagoides farinae

Mite dialysate prepared from an extract of house dust mite, Dermatophagoides farinae, suppressed 48-h homologous passive cutaneous anaphylaxis (PCA) in rats caused by a non-dialyzable fraction of the mite extract (mite antigen), and the suppression was dose-dependent with a high specificity for the antigen. The mite dialysate itself slightly elicited the PCA. Fraction 3 obtained from the mite dialysate by means of DEAE-Sephadex A-25 column chromatography suppressed PCA in rats and guinea pigs more potently than mite dialysate. Histamine release from sensitized rat peritoneal exudate cells (PEC) induced by the mite antigen was suppressed in a dose-dependent manner when the PEC had been previously incubated with fraction 3. However, incubation of the PEC with fraction 3 caused a significant release of histamine compared to the spontaneous value. Fraction 3 clearly inhibited the passive hemagglutination of the mite antigen-conjugated sheep red blood cells caused by rat hyperimmunized serum. From these results it was considered that certain haptenic substances might be present in the mite dialysate.