Monoclonal Antibodies Inhibiting Invasion of Cultured Cells by Eimeria tenella Sporozoites

Monoclonal antibodies (MoAbs) secreted by 12 hybridomas and reactive with the surface antigens of E. tenella sporozoites were produced. These MoAbs designated as KC-1 to KC-12 were characterized as IgG₃K. In Western blot analysis, these MoAbs reacted with only one polypeptide band of sporozoite antigens having a molecular mass of 25 kDa. All the MoAbs were reactive with sporozoites. trophozoites, immature and mature first generation schizonts, first generation merozoites, and the interior structure of sporulating oocysts of E. tenella, however, not with any of the methanol-fixed sporozoites of E. acervulina, E. mitis, E. maxima, E. brunetti, E. necatrix and E. praecox. Invasion of primary culture of chicken kidney cells by E. tenella sporozoites was significantly inhibited by several of the MoAbs. These results suggest that these MoAbs recognizing the E. tenella-specific surface molecule are involved in the invasion of sporozoites into host cells.