DEVELOPMENTALLY-REGULATED LECTINS IN EIMERIA SPECIES AND THEIR ROLE IN AVIAN COCCIDIOSIS

Avian coccidiosis caused by Eimeria species is characterized by rather specific site infections of the intestine. We used hemagglutination a nd hemagglutination inhibition assays on various developmental stages of Eimeria tenella and on sporozoites of Eimeria acervulina and Eimeri a maxima to assay for parasite lectins. Various monosaccharides, polys accharides, and glycoproteins were used to demonstrate differences in sugar specificity of the lectins between these species. Surface lectin s were found on the primary infective stage, i.e., sporozoites, but no t on merozoites or unsporulated oocysts. Also, there were differences in the specificities of the various sugar lectins among the different parasite species. Furthermore, there was a dose-dependent reduction of infection of tissue culture cells by sporozoites of E. tenella that w ere continuously exposed to fetuin, 1 of the specific inhibitors of th e lectin. The results of our study are unique in that in 3 species of avian Eimeria all have a lectin on their sporozoites, but the lectins for each species have different sugar specificities. We hypothesize th at these lectins found on the surface of the sporozoites may play a ro le in determining the site of infection within the intestine of the ho st.