Immune responses to ragweed pollen antigens

Abstract

1. 1. Series of rabbits were experimentally immunized with either intact grains of whole ragweed pollen or one of its derivative preparations, including saline extracts, soluble cytoplasm obtained by subjecting pollen grains to the disintegrating effects of ultrasonic and supersonic vibrations, ball-mill-ground whole pollen hydrochloride, and ether-soluble fraction (“pollen oil”). 2. 2. The antisera obtained from these animals were employed as indicators of antigenic components of ragweed pollen in determinations of patterns of precipitin test reactions employing agar gel diffusion plate techniques (Ouchterlony). 3. 3. The interpretation of antigen-antibody precipitin band patterns suggests the following: 3.1. (a) The maximum number of antigenic components in ragweed pollen that could be determined by this technique was six. 3.2. (b) There is both qualitative and quantitative antigenic superiority in the whole ragweed pollen grain, which could not be duplicated with immunization procedures employing preparations of pollen extracts or soluble pollen cytoplasm. 3.3. (c) Conversion of the whole pollen grain to a soluble extract may result in an antigenic alteration involving as many as two pollen constituents. 3.4. (d) Soluble pollen cytoplasm obtained by disrupting the integrity of the ectine and cell walls of the pollen grain by mechanical procedures may undergo a loss of two or three antigenic components. 3.5. (e) Preliminary defatting of the pollen with ether results in only minor antigenic effects, but the addition of glycerin to a saline ragweed extract enhances its antigenicity. 3.6. (f) Ragweed pollen subjected to standard and prolonged extraction procedures contains effective residual antigenicity. 3.7. (g) Ragweed pollen oil contained one antigenic fraction of undetermined nature capable of inducing a serum precipitating antibody response. 4. 4. In rabbits passively sensitized with homologous species antiserum to ragweed and subsequently challenged with specific soluble pollen extract, microscopic lesions of periarteritis and panarteritis of the pulmonary vasculature were demonstrated. These lesions could not be found in rabbits receiving either the antiserum or the pollen antigen alone. The development of hypersensitivity vasculitis as a tissue response to the in vivo ragweed pollen antigen-antibody reaction is suggested.