Host Cell Specificity on The Entry of Eimeria stiedai Sporozoites in Cultured Cells

Abstract

Invasion specificity of Eimeria stiedai sporozoites to cultured rabbit liver biliary cells, parenchymal hepatocytes and kidney cells was monitored. lntracellular　sporozoites　were　observed　in　liver　biliary　epithelial　cells, as early as 3 hrs when an infection rate of 5% was recorded. Infection rate for rabbit liver biliary epithelial cells was monitored for 6 hrs and increased to approximately 9％ at this time. No intracellular parasites were found in rabbit parenchymal hepatocytes and rabbit kidney cells, even on prolonged culturing. In the liver biliary epithelial cells inoculated with fixed sporozoites, no intracellular parasites were found. Sporozoites attached on the cell surface of the liver biliary epithelial cells fixed with paraformaldehyde, but did not penetrate. Serum of mice immunized with rabbit liver biliary epithelial cells, showed antibody reactivity to liver biliary epithelial cells, higher than, that of rabbit parenchymal hepatocytes and rabbit kidney cells. After absorption with parenchymal hepatocytes, antibody reactivity to liver biliary epithelial cells in the serum still retained. Sporozoite penetration activity in the liver biliary epithelial cells reduced by the supplement of the serum of mice immunized with rabbit liver biliary epithelial cells in the culture medium. These results suggest that Eimeria stiedai sporozoites penetrate the hepatobiliary cells selectively and these epithelial cells have the sporozoite binding site(s) which might be identified by specific antibody.