Immunocytochemical localization of antigens in adult worms of Trichinella spiralis recognized by Fischer rats.

We demonstrate the tissue localization, in adult Trichinella spiralis, of antigens recognized by Fischer rat sera at 32 weeks postinfection. Immunodominant antigens were located in a wide variety of tissues, including type 1 stichocyte granules, stichocyte cytoplasm, the canalicular tree, hemolymph, hypodermis, hypodermal glands, cord cytoplasm, intestinal-gland cell granules, membranous structures in the midgut epithelium, midgut-occupying substance, brush border, hindgut epithelial cytoplasm, hindgut cuticle, vaginal cuticle, epithelial cytoplasm of the female genital tract, microvilli and discrete areas of the ovum, embryo sheath, intersperm space, discrete areas in immature sperm, small granules and cup-shaped membrane structures of sperm, and exocrine granules in the seminal vesicle and ejaculatory duct. A small amount of antigen was located in the inner layers of the genital portion of the body cuticle. The precise localization of antigens in adult worms should form a basis for better analysis of T. spiralis-related immunology.