Submitted to: Coccidiosis International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 12, 1999
Publication Date: N/A
Technical Abstract: Coccidiosis, an intestinal infection caused by intracellular protozoan parasites belonging to several different species of Eimeria seriously impairs the growth and feed utilization of livestock and poultry. Due to complex life cycle of orgnism and intricate host immune responses to Eimeria, coccidia vaccine development has been difficult. Understanding of fbasic immunobiology of pertinent host-parasite interactions is necessary for the development of novel control strategy. Although chickens infected with Eimeria spp. produce parasite-specific antibodies in both the circulation and mucosal secretions, antibody mediated responses play a minor role in protection against coccidiosis. Rather, increasing evidence shows that cell-mediated immunity plays a major role in resistance to coccidious. T-lymphocytes appear to respond to coccidious both through cytokine production and a direct cytotoxic attack on infect cells. The exact mechanism by which T-cells eliminate the parasites, however, remain to be investigated. Since it is crucial to understand the intestinal immune system in order to develop an immunological control strategy against any intestinal diseaes, this presentation will summarize our current understanding of the avian intestinal immune and mucosal immune responses to Eimeria, to provide a conceptual overview of the complex molecular and cellular events involved in intestinal responses to enteric pathogens.