Transfected Eimeria tenella could complete its endogenous development in vitro

Live attenuated coccidiosis vaccines could be used Lis powerfull carriers, expressing exogenous viral and bacterial antigens, to induce protective immunity against pathogenic organisms. We investigated the ability of Eimeria tenella to express an exogenous in vitro. g g Eimeria tenella sporozoites were transfected with the plasmid pH4-2EYFP-Actin3 containing the yellow fluorescent protein gene (yfp) and inoculated into primary chicken kidney cells (PCKCs), followed by incubation at 41 C in a 5% CO2 chamber. Fluorescent sporozoites were observed as early as 15-20 hi post-inoculation (Pl). Fluorescence displayed by the expressed YFP protein was visible throughout the schizogony and gametogony stages of the transfected E. tenella. Fluorescent oocysts were found between 200-327 hr Pl. Higher fluorescence intensity was observed in the nucleus than in other compartments of, the transfectants. while little or no fluorescence was seen in the refractile globule. The diversity of schizonts, particularly of the first generation, was presented by fluorescent nuclei arranged in different patterns. Our results demonstrated the ability of E. tenella to express, an exogenous gene throughout the endogenous development in vitro. Completion of the endogenous development of transfected E. tenella in cell cultures will facilitate (tic study of foreign antigen expression in Eimeria spp., paying the way for the development of an Eimeria spp. vector vaccine that also carries and delivers other vaccines by oral administration.