Molecular cloning and immunological analysis of immunodominant piroplasm surface proteins of Theileria sergenti and T. buffeli.

cDNA libraries of Theileria sergenti and T. buffeli piroplasms were constructed in lambda gt11 and screened with rabbit anti-piroplasm sera. A major antigen of T. sergenti (33 kDa) and that of T. buffeli (34 kDa) was identified from the recombinant phages by using recombinant antigen-selected monospecific antibodies. The reactivities of the cloned proteins with rabbit antisera, infected calf sera and mouse monoclonal antibody suggested that the 33 and 34 kDa proteins expressed species-common and species-specific epitopes. The DNA probes from these recombinant clones showed species-specific hybridizations in Southern blotting with genomic DNA from piroplasms. These results indicate that the Japanese T. sergenti can be distinguishable from the Australian T. buffeli with regard to a polymorphism of the major immunodominant proteins of piroplasm.