Submitted to: Avian Immunology Research Group Abstract
Publication Type: Proceedings
Publication Acceptance Date: April 1, 2001
Publication Date: N/A
Interpretive Summary: Chicken coccidiosis is caused by Eimeria species which are intracellular parasites. These parasites infect the host intestine causing severe intestinal damage. Chickens infected with Eimeria are unable to grow normally due to poor nutrient absorption by the damaged intestine. Currently, prophylactic medication is a major method to control coccidiosis. However, due to increasing incidence of drug-resistance of these parasites, new strategy to control coccidiosis is needed. In this report, ARS scientists have genetically engineered recombinant chicken antibody molecules which are specific for Eimeria parasite proteins. These recombinant chicken antibodies will be used to block parasite invasion and to reduce economic loss due to coccidiosis.
Chicken hybridomas secreting monoclonal antibodies against Eimeria acervulina sporozoites were produced to identify parasite proteins involved in host cell invasion. While most antibodies recognized uncharacterized parasite surface proteins, two were identified with reactivity against apical complex proteins located at the anterior tip of sporozoites. To express high concentration of these antibodies for potential application a immunotherapeutic reagents, a single chain fragment variable (ScFv) region gene was constructed by PCR amplification of the variable heavy (VH) and light (VL) chain genes with a flexible linker. By indirect immunofluorescence, recombinant ScFv antibody expressed in E. coli showed identical binding specificity as the original monoclonal antibody against E. acervulina and E. tenella sporozoites, staining the apical complex and thus demonstrating reactivity against native parasite protein.