Technology Description: The invention is a way to detect the parasite, Eimeria acervulina using monoclonal antibodies from stable chicken hybridomas. These antibodies target specific structures on the parasite, which are present during a particular development stage known as the sporozoite stage. The hybridoma is made by fusing a thymidine kinase (TK) -deficient chicken myeloma with spleen cells from chickens immunized with sporozoite antigens from a location on the anterior tip of E. acervulina sporozoites. The monoclonal antibody recognizes sporozoite proteins from that location. The monoclonal antibody has been shown to inhibit the invasion of sporozoites into CD8+ T cells in vitro thereby indicating its role in the recognition of host cells during the invasion process following infection with Eimeria parasites. Reference: Please refer to USPN 6,451,984, "Chicken Monoclonal Antibodies Specific for Coccidial Antigens Involved in Invasion of Host Lymphocytes," which issued September 17, 2002. Inventor: Hyun Lillehoj/Marjorie B. Nichols USDA-ARS-BA Protozoan Diseases Laboratory Beltsville, MD 20705-2350 (301)504-8300