MOLECULAR ANALYSIS OF ANTIGENS TARGETED BY PROTECTIVE ANTIBODIES IN RAPID EXPULSION OF TRICHINELLA-SPIRALIS

Rapid expulsion is a protective immune mechanism which eliminates as m uch as 99% of a challenge infection of Trichinella spiralis muscle lar vae from the gastrointestinal tract of suckling rats. Protective monoc lonal antibodies (mAbs) generated against larval excretory-secretory a ntigens (ESA) specifically recognize a 45-kDa glycoprotein, gp45, in a ddition to a distinct profile of other cross-reactive antigens that ar e also recognized by non-protective mAbs. Recent data indicate that pr otective mAbs recognize carbohydrate epitopes. To complement biochemic al studies on the target(s) of rapid expulsion, we describe here the c loning and characterization of the cDNA, TspE1, which belongs to a mul tigene family and encodes several larval proteins in the 40-50-kDa ran ge. A second cDNA, TspM6 encodes a 45-kDa antigen and is homologous to the published sequence of gp45. Anti-TspE1 antibodies detected antige ns within beta- and gamma-stichocytes while anti-TspM6 antibodies dete cted antigens within alpha-stichocytes of the secretory organs of musc le larvae. Sequence analysis has provided no functional information on the encoded gene products. Neither recombinant antigen is recognized by the mAbs but native parasite molecules with peptide homology to bot h the TspE1 and TspM6 recombinant antigens bear the glycan recognized by the protective mAbs. These molecules are candidate targets in rapid expulsion.