We have investigated the role of glycans on Trichinella spiralis antig
ens in recognition by rat monoclonal antibodies (mAbs) which protect r
at pups against challenge with the parasite. In pups born to infected
dams or pups passively immunized with mAbs, antibodies eliminate a cha
llenge dose from the intestine within hours ((rapid expulsion'). Becau
se such dramatic protection can be afforded by mAbs, we have sought to
characterize the parasite antigens they target. In this report we sho
w that protective antibodies were unable to bind excretory/secretory (
ES) antigens deglycosylated with trifluoromethanesulphonic acid (TFMS)
. In addition, oligosaccharides isolated from glycoproteins by alkalin
e hydrolysis or peptide: N glycosidase F (PNGase F) digestion were bou
nd by protective, but not non-protective, mAbs. Glycans affinity purif
ied with protective mAb 9D bound to all but one protective mAb. These
antibodies have been shown previously to bind to the surfaces of intac
t larvae, indicating that the glycan is exposed on the parasite surfac
e. Candidate glycans that may be involved in binding protective mAbs h
ave unusual tri- and tetra-antennary structures with terminal tyvelose
moieties (Reason et al., Glycobiology, 4, 000-000, 1994). Coating of
the larval surface with such glycans may serve to protect the parasite
and its secreted products from enzymatic attack as the parasite trave
ls to and resides in its epithelial niche.