PARTICIPATION OF PARASITE SURFACE GLYCOPROTEINS IN ANTIBODY-MEDIATED PROTECTION OF EPITHELIAL-CELLS AGAINST TRICHINELLA-SPIRALIS

The L1 stage of the parasitic nematode Trichinella spiralis displays o n its surface glycoproteins that are immunologically cross-reactive wi th several larval excretory-secretory (ES) products, The basis for the crossreactivity is tyvelose, the terminal residue on the complex glyc ans shared by these surface and ES glycoproteins, In neonatal rats, ty velose-specific monoclonal antibodies mediate the expulsion of larvae from the intestine. The aim of the studies described in this report wa s to determine holy antibody binding to larval surfaces contributes to expulsion. In these experiments, which involve an in vitro assay of e pithelial cell invasion, surface proteins on living larvae were biotin ylated to distinguish them from ES products. Biotinylated and nonbioti nylated larvae were cocultured with avidin, biotin-specific antibodies , or anti-tyvelose monoclonal antibodies. Biotinylated larvae cultured with avidin or biotin-specific antibodies invaded Madin-Darby canine kidney (MDCK) cells equally as well as biotinylated larvae cultured wi th medium alone. Anti-tyvelose monoclonal antibodies were highly prote ctive in this assay; however, biotinylation of larval surfaces hindere d the ability of anti-tyvelose monoclonal antibodies to prevent larval invasion of epithelial cells. This correlated with a reduction in the binding of anti-tyvelose antibody to biotinylated larval surfaces. Ou r results indicate that antibody binding to surface glycoproteins cont ributes to protection against T,spiralis invasion but that surface bin ding alone is not sufficient for protection, Our findings support that notion that protection is effected by cross-linking of ES products to surface antigens.