title: Immune response of channel catfish to ciliary antigens of Ichthyophthirius multifiliis.
abstract: Channel catfish were rendered immune to the protozoan pathogen, Ichthyophthirius multifiliis, by exposure to sublethal infections. Sera from test animals were then screened for antibodies against the parasite using enzyme-linked immunoassays. Ichthyophthirius cilia were blotted onto nitrocellulose filters and reacted with catfish sera, followed by rabbit anti-catfish Ig antibodies coupled to horseradish peroxidase. Subsequent color development revealed the presence of anti-ciliary antibodies in a number of fish tested. Reactions appeared to be highly specific; little cross-reactivity was seen in equivalent assays with heterologous cilia from Tetrahymena. Ciliary antigens were associated predominantly with a membrane polypeptide fraction isolated from intact cilia by phase separation in solutions of the nonionic detergent, Triton X-114. The relative levels of anti-ciliary antibodies in sera from individual fish were quantitated by photometric scanning of immunoblot assays. A strong correlation (P less than .03) was found between antibody levels and the ability of sera to agglutinate live parasites in vitro.
mesh_terms: D000371:Agglutination; D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D000953:Antigens, Protozoan / Q000276:immunology; D002397:Catfishes / Q000276:immunology*; D002923:Cilia / Q000276:immunology; D016798:Ciliophora / Q000276:immunology*; D003429:Cross Reactions; D005393:Fish Diseases / Q000276:immunology; D007059:Ictaluridae / Q000276:immunology*; D011528:Protozoan Infections / Q000276:immunology; D011529:Protozoan Infections, Animal; D013045:Species Specificity; D013768:Tetrahymena / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan