Intestinal mucus entrapment of Trichinella spiralis larvae induced by specific antibodies

Abstract

Entrapment of muscle larvae (ML) occurred in vitro when antibodies specific for Trichinella spiralis were added directly to intestinal mucus from normal non-immunized rats or when mucus was collected from pups suckling a T. spiralis-infected dam. Normal rat serum immunoglobulins failed to promote mucus entrapment and complement did not appear to play a part in the entrapment process. Differences were not observed in the efficiency of entrapment of ML by mucus harvested from different regions of the small intestine. Employing a panel of monoclonal antibodies (mAb) specific for excretory-secretory antigen (ESA), we attempted to dissociate antibody-mediated protection from mucus entrapment. We assessed mucus entrapment and rapid expulsion by these mAb in vivo, and observed protection in the absence of significant, immediate mucus entrapment in two cases. In addition, we measured mucus entrapment of ML in two in vitro assays. One assay employed intestinal mucus harvested from pups suckling dams that had been injected i.v. with a mAb. Results confirmed those obtained in vivo and indicated that antibodies were present in the intestinal lumina of passively immunized pups. In the second in vitro assay, mAb were added individually to mucus from pups suckling non-immunized dams. Results from these assays suggested that certain antibody isotypes may be processed in vivo in ways that influence, either positively or negatively, their abilities to cause mucus entrapment.