TWENTY-SECOND ANNUAL EASTERN FISH HEALTH WORKSHOP ROYAL PAVILLION RESORT, ATLANTIC BEACH, NC MARCH 18 - 20, 1997 Clonal Rainbow Trout (Oncorhynchus mykiss) Derived by Chromosome Set Manipulation As Immunological Models For Fish Disease Research Sandra S. Ristow1, Stephen L. Kaattari2 and Gary H. Thorgaard3. Departments of Animal Sciences1, Zoology3, and Genetics and Cell Biology3, Washington State University, Pullman WA 99164 and Virginia Institute of Marine Sciences2, Gloucester Point VA 23062. Homozygous clones of rainbow trout (Oncorhynchus mykiss) were derived by chromosome set manipulation techniques of androgenesis, a method in which irradiated eggs are fertilized by normal spermatozoa yielding progeny with all-paternal inheritance, and gynogenesis, a method in which normal eggs are activated to develop by irradiated sperm, yielding progeny with all-maternal inheritance. Homozygosity and genetic uniformity of clonal lines were determined by DNA fingerprinting which demonstrated identical restriction fragment length polymorphisms (RFLP) using multilocus probes. Isogenic, heterozygous families were derived by mating homozygous females and homozygous males from different clonal lines. Grafting experiments showed that members of isogenic families retained allografts allografts xenografts from chinook salmon (Oncorhynchus tshawytcha) were rejected. Peripheral blood of the homozygous lines was examined for natural cytotoxic cell (NCC) activity. Studies revealed that the Arlee line of trout possesses minimal NCC in its peripheral blood; however, it is not the fish equivalent of the Chediak-Hagashi Syndrome in mammals because it lacks the characteristic large granules in leucocytes. The b chain of the major histocompatibility locus of each of the homozygous fish has been sequenced and reveals high sequence homology among the lines. Two of the lines most disparate from one another in b chain sequence, Hot Creek and Arlee, exhibit different antibody responses against TNP insulin. In addition, long term cell lines have been established from three of the lines (Arlee, Hot Creek and OSU 142). DNA fingerprinting revealed virtually the same RFLP patterns in the cell lines and the parent trout from which they were derived, with differences in band intensities possibly reflecting some aneuploidy in the cell lines. Return to 22nd Annual Eastern Fish Health Workshop Return to Leetown Science Center Home Page