Techniques for isolation and characterization of apical organelles from Eimeria tenella sporozoites

Apical organelles contain molecules that are of critical importance for the interaction of all apicomplexan parasites with their target host cells. Thus, there is considerable interest in characterizing and understanding the function of molecules that reside in these organelles. Large numbers of surface-sterilized oocysts of Eimeria tenella, an apicomplexan coccidian of the chicken, can be routinely obtained from the animal host, and invasive sporozoites, which contain abundant apical organelles, can be rapidly prepared from these oocysts in the laboratory. Thus, E. tenella is proving to be an amenable parasite for subcellular fractionation techniques that allow the direct isolation and characterization of apical organelles. In this paper, a series of protocols is described for the large-scale culture of E. tenella parasites, the preparation of invasive sporozoites, the isolation of apical organelles, and the use of in vitro culture for localization and functional studies.