Diagnostic and protective antigen gene sequences of ichthyophthirius

摘要

The ciliated protozoan Tetrahymena exemplifies a recombinant system for the expression of heterologous nucleic acids, preferably on the plasma membrane surface. Integration of a heterologous nucleic acid into the beta -tubulin gene, BTU1, of a paclitaxel-sensitive T. thermophila mutant that possesses btul-1K350M beta -tubulin allele allows screening for transformants using negative selection, as transformants have restored paclitaxel resistance. Transgenic ciliated protozoa of the invention can serve as live vaccines. For example, transgenic Tetrahymena expressingIchthyophthirius multifiliis i-antigen protein on their surface are effective vehicles for vaccination of freshwater fish against infection by I. multifiliis.