Studies in bacterial allergy: VI. Hapten aerosol desensitization of guinea pigs passively sensitized to specific pneumococcal polysaccharides

Abstract

I. Type 6 antipneLullococca.1 rabbit serum intraperitoneally sensitize guinea pigs so that an aerosol of type 6 polysaccharide produces reactions va,rying from moderate dyspnea to anaphylactic death. 2. The results of aerosol and intravenous challenges with polysaccharides are not parallel. Negative aerosol challenges may be followed by anaphylactic death from intravenous challenge. 3. There is a definite threshold of effective concentration of aerosol polysaccharide and of histamine. 4. Desensitization follows exposure to reacting aerosol. The pattern of desensitization varies. Tt may be noted : a. Following recovery, while still in the fog, from moderately severe reactions. b. Following several exposures to the fog, each causing decreasingly intense reactions. c. Or it may be complete after one severe reaction. 5. Desensitization against one concentration of polysaccharide may desensitize completely to aerosol challenge will respond by ana.phylactic death to intravenous challenge of the same strength of polysaccharide. Quantitative factors of time and polysaccharide absorbed have not been studied yet. 6. Local aerosol desensitization does not desensitize against histamine.