Submitted to: Japanese German Cooperative Symposium on Protozoan Diseases
Publication Type: Abstract Only
Publication Acceptance Date: November 2, 1997
Publication Date: N/A
The widespread occurrence of avian coccidiosis has ranked it as the major parasitic disease of poultry. After initial infection with Eimeria, chickens acquire immunity to reinfection and much effort is currently underway to identify potential vaccine antigens capable of inducing protective host immune response. Cell-mediated immunity is the main line of defence against coccidial infection. Recent studies have identified CD8 positive T cells as the major effector cells. Shortly following infection, sporozoites are transported from the villus epithelial cells to crypt epithelial cells most likely in CD8 positive T lymphocytes and macrophages. Recently, we have reported that the chicken mAb 6D-12-G10 significantly inhibited sporozoite invasion of CD8 positive T cells in vitro. Immunoelectron microscopic study revealed that this mAb reacts with the conoid of Eimeria acervulina sporozoites. In this study, we examined the cross-reactivity of mAb 6D-12-G10 against different Eimeria species and related coccidian parasites of different genus. By confocal laser scanning microscopy, the conoid of sporozoites from six different Eimeria species (Eimeria brunetti, Eimeria maxima, Eimeria mitis, Eimeria necatrix, Eimeria praecox and Eimeria tenella) were reactive with this mAb. Furthermore, this mAb also showed cross-reactivity with tachyzoites from closely related coccidian parasites including Neospora and Toxoplasma. These results indicate that the mAb 6D-12-G10 identifies a conserved epitope on the conoid which is important in host cell invasion by the apicomplexan parasites.