Authors

G Sanchez-Arsuaga¹; D Blake¹; F Tomley¹; V Marugan-Hernandez¹;  ¹ Royal Veterinary College- University of London, UK

Discussion

Poultry coccidiosis caused by Eimeria spp. is a severe intestinal disease that is estimated to cost chicken producers approximately £10.4 billion worldwide annually. Treatment and prevention principally rely on the use of coccidiostat in the feed. The second most effective way to prevent coccidiosis is the use of live vaccines, but the use of these vaccines has been limited to breeder and layer chickens due to the relatively high cost and limited production capacity. New generation vaccines are needed and research in proteins related to host-parasite interaction could be of interest. Dense granules (DG) are known to be a major storage organelle for parasitophorous vacuole proteins in Eimeria close related parasites such as Toxoplasma gondii. Nevertheless, their presence as independent organelles has not been proved in Eimeria and limited information is available regarding DG proteins (EtGRAs).
Over-expression found in some EtGRAs during invasion and early development, and the positive outcome of certain GRA proteins as vaccines in Toxoplasma leads to hypothesize EtGRAs as possible vaccine candidates.
Herein, an in-silico characterization of three selected potential GRA proteins was carried out. Secondly, a genetic approach was executed, looking for possible SNP’s and, therefore, elucidating preexisting genetic diversity and function essentiality, improving prospects for vaccine use. In addition, candidates were expressed in sporozoites as fusions with a fluorescent reporter (mCherry) aimed to identify intracellular localization and potential existence of DG-like organelles. To develop a deeper understanding of their storage compartments, a polyclonal antibody against EtGRA9 is being produced and will be used for immunogold labelling and election microscopy to identify the precise structure where the candidate is located before and after invasion.