The Antigenic Properties of Extracts of Horse Dander

Abstract

Summary These experiments show conclusively that guinea-pigs may be readily sensitized to extracts of horse dander that contain a total nitrogen content of approximately 40 mgm. per 100 cc., and that are preserved at a reaction of approximately pH 7.4. In many instances the sensitization may be of such comparatively high degree that 0.05 cc. of extract injected intravenously will cause characteristic anaphylactic death within three to four minutes, or that the uterine muscle of sensitized guinea-pigs in a Dale bath of 200 cc. of Locke's solution will contract promptly on the addition of from 0.01 to 0.001 cc. of extract. The sensitization is specific for the antigen or antigens that are contained in the extract of horse dander, for guinea-pigs sensitized to horse dander extract do not react to horse serum, while guinea-pigs sensitized to horse serum do not react to horse dander extract. When guinea-pigs highly sensitized to horse dander extract are injected intravenously with sublethal doses of the extract, they are desensitized twenty-four hours later to intravenous injections of many times the lethal dose of extract. Likewise the uteri of virgin guinea-pigs which have reacted to additions of small amounts of the extracts are insensitive to further additions of large amounts of the extract. It is possible to conclude, therefore, from these experiments that extracts of horse dander contain an antigen or antigens which give anaphylactic reactions in guinea-pigs that are precisely the same as the anaphylactic reactions produced by any one of a large number of proteins.