Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2001
Publication Date: N/A
Interpretive Summary: Coccidiosis is the major parasitic disease of economic importance for the poultry industry and is caused by an intestinal protozoa belonging to several species of the genus Eimeria. Although the anti-coccidial drugs in poultry feed have been successfully used to control coccidiosis, alternative control strategies are urgently needed due to the increasing emergence of drug resistant parasites in the commercial settings. In this regard, ARS scientists, in collaboration with scientists at Changwon and Seoul National Universities in Korea, identified immunogenic parasite molecules which bind to the host cell surface receptors using chicken hybridoma technology. This report describes the method which was used to develop novel recombinant chicken antibody molecules which recognize a coccidia receptor protein for the first time. ARS scientists expressed this recombinant chicken antibody gene in E. coli and demonstrated their specific recognition of E. acervulina sporozoites and merozoites. This recombinant antibody will be tested for its ability to block parasite invasion of host cells in vivo. Ability to manipulate this antibody gene will facilitate the development of novel immunological intervention strategy against coccidiosis and will reduce the economic losses due to coccidiosis.
We previously generated a chicken monoclonal antibody (mAb) reactive with an apical complex protein at the anterior tip of E. acervulina sporozoites that inhibited parasite invasion in vitro. Because this mAb was produced at low amount from the original hybridoma cells, an single chain variable fragment (scFv) antibody was constructed by amplification of the corresponding VH and VL genes and expressed in E. coli. The scFv antibody was produced at a minimum of 7 mg/l and exhibited virtually identical antigen reactivity as the original mAb.