Passive protection of chickens against Eimeria tenella infection by monoclonal antibody.

Monoclonal antibodies reactive with the surface of Eimeria tenella sporozoites were produced in mice. This paper concerns one of these monoclonal antibodies, designated 1073.10, which agglutinated sporozoites in vitro and lysed the parasite in the presence of complement. This treatment neutralized sporozoite infections when the treated parasites were injected into the ceca of normal chickens. Passive transfer of ammonium sulfate-precipitated 1073.10 ascites fluid into 2- to 3-day-old or 3-week-old chickens conferred protection against challenge infection with E. tenella. These studies show that serum antibody may play a role in immunity to coccidiosis and that the sporozoite surface epitope recognized by 1073.10 is a possible vaccine candidate antigen.