Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 15, 2004
Publication Date: May 5, 2004
Citation: Constantinoiu, C.C., Lillehoj, H.S., Matsubayashi, M., Hoshoda, Y., Tani, H., Matsuda, J., Sasao, K., Baba, E. 2004. Analysis of cross reacivity of 5 new chicken monoclonal antiodies which recognize the apical complex of eimeria using confoid laser immun-fluorescent assay. Veterinary Parasitology. 118:29-35.
Interpretive Summary: Coccidiosis is the most important protozoan disease of poultry due to its significant economic impact on poultry industry. Although the poultry industry has relied upon chemoprophylaxis to control coccidiosis, alternative control strategies are needed due to high costs associated with development of new drugs, rapid emergence of drug resistance field strains of Eimeria, and the public's attitude toward the drug treated-meat products. Therefore, new strategies involving recombinant vaccines and genetic improvement of poultry immunity are now being actively pursued. In this study, ARS scientist and Osaka University scientists collaborated to develop new antibodies to identify potential vaccine antigens of Eimeria. Characterization of these antibodies revealed their usefulness as diagnostic reagents. The results of this study will enhance our understanding of parasite biology and facilitate the development of recombinant vaccine for avian coccidiosis.
In this research paper, the characterization of 5 chicken monoclonal antibodies (mAbs) that were developed against apical complex antigens on the apical tip of sporozoites from chicken Eimeria spp. is realized and the mAbs reactivity to merozoites belonging to Eimeria acervulina is tested. Using immuno-fluorescence assay (IFA), two mAbs were identified which showed binding to the antigens common to sporozoites of E. acervulina and E. brunetti (mAb HE-4) and to sporozoites of all chicken Eimeria species (mAb 8E-1). The mAbs 8E-1 and HE-4 recognized antigens localized on the apical tip of merozoites from all different stages of development that we examined. The target antigens which are recognized by these two mAbs are common antigens of apical complex and probably involved in host-cell recognition and invasion. Another mAb, 8C-3 which identified an antigen shared by sporozoites and sporocysts of E. acervulina reacted very weak and inconstantly with the merozoites whereas the mAbs 5D-11 and 8D-2 that recognized antigens shared by the sporozoites of E. acervulina and E. maxima (mAb 5D-11) and E. acervulina and E. brunetti (mAb 8D-2) did not react with the merozoites from any generation. Differences regarding the method of fixation were noticed: air dried merozoites stained most intensely followed by acetone and methanol fixed parasites and the glutaraldehyde-fixed parasites did not stain at all. Collectively, these results showed that the invasive stages of chicken Eimeria spp. share cross reactive apical complex antigens which are inter-specie and inter-generation-specific that might represent a potential recombinant vaccine.