THE HUMORAL IMMUNE-RESPONSE OF TURBOT, SCOPHTHALMUS-MAXIMUS L, TO SPORE-SURFACE ANTIGENS OF MICROSPORIDIAN PARASITES

Experiments based on enzyme-linked immunosorbent assay (ELISA) reveale d considerable antigenic homology in turbot between two species of mic rosporidian, Tehramicra brevifilum (a parasite of the turbot Scophthal mus maximus) and Glugea caulleryi (a parasite of the lesser sand-eel, Ammodytes tobianus). We next investigated whether G. caulleryi is able to suppress the turbot immune response. Intraperitoneal inoculation o f turbot with G. caulleryi spores (whether heat-killed or viable) did not suppress the humoral immune response to injection of G. caulleryi spores plus adjuvant 15 days later, in fact, specific serum antibody l evels (as revealed by ELISA) reached maximum levels by about Day 30 po st re-exposure. Similar results were obtained with cellular enzyme-lin ked immunosorbent assay: 15 days after injection with G. caulleryi spo res plus adjuvant, specific antibody secretion rate was higher in turb ot which had been pre-exposed to G. caulleryi spores than in turbot wh ich had not been pre-exposed.