SEROLOGICAL REACTIONS AND SPECIES SPECIFICITY OF SOME HELMINTHS

Abstract

The precipitin reaction was employed to differentiate spp. and to determine interrelationships. Materials for establishing the time at which zoological specificity is attained were supplied by several stages in the life cycles of the trematodes, Parorchis acanthus, Crypto-cotyle lingua and Zygocotyle lunata, and the cestode, Taenia taeniaformis; and Plagitura parva, Siphodera vinal-edwardsii, Dipylidium caninum, Tetrabothrius sp., and Moniezia expansa were used to determine the dilution limits for species specificity and the relationship of spp. Consistent results were obtained by injns. of aqueous solns. containing 40 mg. of dried lipid-free antigen. The reactions were species-specific in antigen dilutions of 1:4000. Larval and adult antigens were not serologically distinct, which indicates that chemical maturity is reached early. Heterolo-gous never exceeded homologous titers, and all reaction titers were confirmed by reciprocal tests. Uniformity of results may be attributed to vacuum desiccation of worms kept in the frozen state, preliminary removal of lipids from desiccated material, control of pH during extractions and tests, control of temps. at which reactions were performed and knowledge of the amt. of antigenic material actually in solution. The serological relationships were in agreement with relationships derived from developmental and morphological considerations. The tests demonstrated that the trematode families Echinostomatidae and Heterophyidae are more closely related to each other than to the Plagi-orchidae or the Paramphistomidae. A closer relationship was expressed by the reactions between Heterophyidae and Plagiorchidae than by tests involving the Heterophyidae and Paramphistomidae, and the kinship between Heterophyidae and Paramphistomidae was closer than that between Echinostomatidae and Paramphistomidae. The titer of reactions between the cestodes, Moniezia expansa and Dipylidium caninum, denotes a close relationship between these 2 spp. which is not equalled by the titers of either sp. with Taenia taeniajormis. No reactions occurred between the trematodes and cestodes which were tested.