Morphology of the alimentary tract of Trichinella spiralis muscle larvae with emphasis on the esophagus

Antigens of trichinella spiralis

Following infection with Trichinella spiralis, the host elicits a strong immune response that causes rapid expulsion of parasites, a reduction in reproductive capacity of the remaining parasites a reduction in the number of larvae recovered from host muscles, and impairment of the mobility of worms in the intestines. The need to identify the antigens that evoke such responses is twofold: (1) to develop immunodiagnostic tools; and (2) to understand the basis of protective immunity. In this review, Yuzo Takahashi describes the antigenic profiles of T. spiralis, emphasizing immunocytochemical findings.

Ultrastructural localization of antigenic substances in Trichinella spiralis

The in situ localization of antigenic substances in Trichinella spiralis muscle larvae was demonstrated at the subcellular level. Larvae recovered from mouse muscle were fixed with half-strength Karnovsky fixative, dehydrated with alcohol, and embedded in LR White resin. Ultrathin sections were incubated with sera from infected Wistar rats and, subsequently, protein A-gold complex. The specificity of the immunostaining was confirmed by a control experiment. Positively immunostaining structures included the stichocyte granules, body cuticle, hindgut cuticle, hypodermis, hemolymph, glycogen aggregates, esophagus-occupying substance (EOS), midgut-occupying substance (MOS), brush border, cytoplasmic granules in the cord, intestinal gland cell granules, and discrete areas in the genital primordial cell. However, the esophageal cuticle, nucleus, nucleolus, mitochondria, rough endoplasmic reticulum, and muscle fibers were negative by immunostaining.