MOLECULAR CHARACTERIZATION OF PEANUT AGGLUTININ-BINDING GLYCOPROTEINSFROM EIMERIA-TENELLA

A group of glycoproteins, which strongly bind peanut agglutinin (PNA) was found in Eimeria tenella. Two major antigenic glycoproteins, Et110 gp and Et35gp, were identified in sporulated oocysts and sporozoites. Molecular characterisation of carbohydrate moieties (lectin binding, e nzymic hydrolysis and monosaccharide composition) revealed that both g lycoproteins are rich in galactose and N-acetylplactosamine, and appea r to be sialylated. Both glycoproteins were susceptible to treatment w ith neuraminidase followed by 0-glycosidase, suggesting that the oligo saccharide chains are attached to the protein by an 0-glycosidic linka ge to serine and/or threonine. Purified Et35gp contained a large numbe r of serine (14) and threonine (33) residues, and was rich in glycine. This protein aggregated after repetitive lyophilisation and migrated on SDS-PAGE gels as an 85,000 protein. Sera against purified Et35gp ra ised in chickens and rabbits, and anti-E. tenella immune chicken serum recognised both antigens on blots and on the surface of sporozoites. Chickens immunised with purified Et35gp were not protected against coc cidial infection.