Development and use of hybridoma antibodies directed against Eimeria acervulina merozoites for cross-reactive and ferritin-labeling studies.

Hybridoma antibodies (Hab) were produced against Eimeria acervulina merozoites that had been separated from extraneous intestinal material by a fiber column technique before injection into mice. The Hab demonstrated three different immunofluorescent-antibody (IFA) patterns of tip, surface, or surface-internal fluorescence in or on the merozoites. Some Hab reacted with round immature schizonts, which were also present in the fiber-cleaned merozoite material. Variations in cross-reactivity were seen with a number of Hab tested by IFA with merozoites, sporozoites, and immature schizonts of different coccidial species. Certain Hab were species- and stage-specific, whereas others cross-reacted with some or all stages or species tested. One Hab apparently reacted with only a small percentage of the E. acervulina merozoites in the fiber-cleaned material. The ferritin (Fe)-labeling technique showed that with one Hab, which gave a surface-internal IFA pattern, there was an irregular clumping of the Fe label along the surface of the immature schizont. A heavier deposit of Fe label was seen on the area of the schizont where the merozoite was beginning to form. A heavy uniform labeling of Fe was seen on the surface of the pellicle of the mature merozoites. These results demonstrate that stage-specific and cross-reactive antigens are present in or on the merozoites of E. acervulina, and as shown with one Hab, surface antigens present on the immature schizont are incorporated onto the mature merozoite.