Immunological study on the mechanisms of local eosinophil infiltrations in helminthic infection.

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This study deals with the possible mechanisms of local eosinophil infiltrations in Angiostrongylus cantonensis infections with special emphasis on parasite-derived eosinophil chemotactic factors and their receptors. The results obtained are sunearized as follows : Guinea-pig-eosinophils possess receptor (s) against eosinophil chemotactic factor (s) (ECF) derived from the young adult wores of A. cantonensis (YA), whereas rateosinophils are devoid of the receptor or, if any, the numbers of the receptor are few. The receptor is proteinaceous and reproducible. Hybridomas prepared from spleen cells of mice igmunized with partially Purified ECF-YA produced 2 kinds of sonoclonal antibodies (mabs) recognizing either 16.1 kD or 85 kD component in YA-whole wore extract. These mAbs were IgGl isotype. Both mAbs werespecifically reactive to ECF-YA, but failed to react to the respective whole worm extracts of A. cantonensis first stage larvae, Metastrangylus apri, Fasciola sp. and Spirometra erinace … More i plerocercoids. Several mAbs against 16.1 kD and 85 kD components all recognized the same corresponding epitopes on 16.1 kD and 85 kD antigens. Both anti-16.1 kD and anti-85 kD mAbs were capable of inhibiting eosinophil chemotactic activity of YA-whole worm extract but the former mAb gave a stronger inhibitory effect. The combination of both mAbs showed a stronger inhibitory effect than either mAb alone. Neither mAbs inhibited the chemotactic activity of ECFs derived from other helminth parasites. An affinity chromatography with anti-16.1 kD mAb succeeded in isolating a 16.1 kD antigen from YA-whole worm extracts. The ECF-YA was localized in the intestinal cytoplasm of the young adult worms. The ECF-YA can be discharged from the worms as an excretory and secretory product. Eosinophils in the cerebrospinal fluid (CSF) of mice infected with A. cantonensis were hypodense, while blood eosinophils from the same animals were normodense. Blood eosinophilia induced by the previous infection with other helminth parasite (Mesocestoides corti) failed to lead to CSF eosinophilia in subsequent A. cantonensis infection. CSF eosinophilia in A. cantonensis infection is probably provoked by ECF-YA and/or cytokines produced by lymphocytes sensitized with A. cantonensis antigens. Less