Use of monoclonal antibodies directed against Eimeria tenella sporozoites to determine stage specificity and in vitro effect on parasite penetration and development.

Three different hybridoma-produced monoclonal antibodies (Ab) were used to study their reactivities with in vitro developmental stages of Eimeria tenella and their effects on sporozoite penetration and intracellular development. One Ab (designated B10) was stage-specific, whereas the other 2 Ab (designated C3 and E5) reacted with various intracellular developmental stages of the coccidia. The E5 Ab interacted with the cytoplasm of cultured cells that were infected with sporozoites at 24 hours after inoculation. All 3 Ab inhibited penetration to various degrees--the one designated B10 having the greatest inhibitory effect. These 3 Ab also inhibited development of the parasite in cell culture, provided that Ab was continuously present in the cell culture medium. Removal of Ab from the medium allowed coccidial development to continue at about the same rate as in controls. A longer pretreatment time of the sporozoites with the Ab before cell inoculation increased the inhibitory effect with respect to both the penetration and the development of the parasite.