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  • Title: The immunological response of the rat to infection with Taenia taeniaeformis. II. Characterization of reaginic antibody and an allergen associated with the larval stage.
    Author: Leid RW, Williams JF.
    Journal: Immunology; 1974 Aug; 27(2):209-25. PubMed ID: 4213990.
    Abstract:
    Skin sensitizing antibody or reagin was detected in rats 19 days after infection with Taenia taeniaeformis eggs. Peak titres were reached on day 32 and thereafter declined. A second dose of eggs was capable of increasing the levels of circulating reagin, even though it was highly unlikely that the embryos had survived more than a transient period of time in the intestinal mucosa. The physicochemical and biological characteristics of this reagin are consistent with those of the rat immunoglobulin designated γE. In no instance was it possible to demonstrate short-term skin sensitization by the rat 7Sγ2a immunoglobulin class, even though previous work had shown that antibodies of this type are produced during infection. All short-term reactivity at 2-6 hours appeared to be a result of reaginic antibody fixation. Reagins were not observed to cross the placenta or be transferred by the colostrum from highly immune females to their offspring. The role of reagin in passive and specific acquired resistance to T. taeniaeformis is discussed and the mechanisms whereby it might be contributing to immunological events in this infection are outlined. An allergen was isolated from cysticerci of T. taeniaeformis which was capable of provoking passive cutaneous anaphylaxis (PCA) reactions in sensitized rats in approximately 5 μg quantities. A single band was obtained in polyacrylamide gel electrophoresis which stained for protein and carbohydrate but not for lipid. Chromatographic and electrophoretic studies indicated that the allergen was very negatively charged at slightly alkaline pH. Activity was completely removed from larval extracts by absorption with a monospecific antiserum prepared against the allergen. The possibility of more than one allergen being associated with cysticerci and adult worms of T. taeniaeformis is discussed. Cross-reactions with other taeniid parasitic extracts were observed but no positive PCA reactions were elicited with extracts prepared from two dissimilar helminths, Schistosoma mansoni and Fasciola hepatica although these parasites are known to cause cross-reactions in field tests. The potential value of the purification procedure is pointed out in the context of the continuing effort to improve the specificity of clinical diagnostic tests based on intradermal reactions.
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