Eimeria adenoeides sporozoites: enhanced invasion of cultured cells previously inoculated with Eimeria acervulina sporozoites

Abstract.

The effects of prior or concurrent administration of Eimeria acervulina on invasion of cultured cells by Eimeria adenoeides sporozoites and possible mechanisms of action were examined. Baby hamster kidney (BHK) cell cultures that were inoculated with E. acervulina sporozoites were significantly more permissive for invasion by E. adenoeides sporozoites than uninoculated cultures. Enhancement of invasion by E. adenoeides did not occur when the two species were inoculated into cultures concurrently, or within 30 h of each other. However, 48 and 72 h after inoculation of BHK cells with E. acervulina, invasion by E. adenoeides sporozoites was significantly greater than invasion in uninoculated cultures. At 96 h postinoculation with E. acervulina, the enhancing effect on invasion was variable. Culture media collected from E. acervulina-inoculated cultures also significantly enhanced invasion by E. adenoeides. Slight changes in proteins of E. acervulina-inoculated versus uninoculated cell cultures were detected by Western blots of biotinylated and nonbiotinylated cells. Biotinylated bands between 10 and 25 kDa increased in the inoculated cultures. In addition, when chicken anti-E. acervulina sporozoite serum was used as a probe, labeling of a 10 kDa antigen increased in the inoculated cultures.