Immunocytolocalization of Two Protection-Inducing Antigens of Trichinella spiralis during Its Enteral Phase in Immune and Non-Immune Mice

Abstract

Monoclonal antibodies (mAb) recognizing epitopes on the 48K (beta stichocyte specific) and the 50/55K antigen (alpha stichocyte specific) were used as first ligands for immunocytolocalization on de-paraffinized sections of infected gut tissue of non-immune and immune CFW strain mice. The enteral phase was studied at 6, 14, 23, 30 hr and 7 days after initiation of infection via the oral route, times corresponding in worm development to the first (L1), second (L2), and third (L3) stage larva and adult. No change in the intensity of the immune reaction with either mAb was noted in parasites developing within immune or non-immune mice for any of the time-points studied. The 48K and the 50/55K antigens were present within the stichocytes at 6 hr. Enterocytes adjacent to some worms also stained positive for both epitopes at this time. Throughout worm development, the amount of each antigen within the worm diminished, until almost none was left at 30 hr. At day 7, the 48K antigen was present within a few stichocyte cells, the canalicular tree, and within the lumen of the midgut. The 50/55K antigen at this time point was localized within only a few stichocyte granules and on the lining of the worm's gut. Embryo stages did not possess either the 48K or 50/55K epitopes. A marked increase in cells bearing IgG in the lamina propria was noted in immune mice when compared with their non-immune counterparts.