An immunocytochemical analysis of a class-specific antibody response against Trichinella spiralis in humans.

The response of different classes of antibodies against antigens of the muscle larvae of Trichinella spiralis was tested using an immunocytochemical approach. Ultrathin sections of resin-embedded larvae were treated with sera from patients with trichinosis, then exposed to a biotinated second antibody and stained with avidin-gold complex. Antibody of the M-class was a major component in the response against a slow-responding group of antigens that included stichocyte granules, the cuticle surface, and the esophagus-occupying substance; a minor component in the response against antigens of the rapid-responding group that included cuticle inner layers, hypodermis, hemolymph, and intestinal gland granules. The response of G-class antibody against the rapid-responding group of antigens was detected in all patients tested, while against the slow-responding group of antigens it was detected in only half of the patients, suggesting that an antibody shift from the M to the G class occurred in some patients. The results, obtained in humans, were similar to those we obtained previously in rats (J. Parasitology, 76,230-239, 1990), suggesting that the rat immune system can serve as an experimental model of human trichinosis.