Analysis of the genes encoding immunodominant piroplasm surface proteins of Theileria sergenti and Theileria buffeli by nucleotide sequencing and polymerase chain reaction.

The nucleotide sequences of the cDNAs encoding a 33-kDa piroplasm protein of Theileria sergenti (p33) and a similar protein of Theileria buffeli (p34) were determined. Both of the genes contained an open reading frame of 849 base pairs. The predicted amino acid sequence of p33 and p34, consisting of 283 residues, showed 82% similarity. A transmembrane hydrophobic domain and signal peptides were predicted. The polymerase chain reaction was used to amplify p33/34 genes from the piroplasm DNA of T. sergenti, T. buffeli and Theileria orientalis. Following amplification, p33 and p34 genes were clearly differentiated using the restriction enzymes sites that were not shared between them. These results indicated that p33 and p34 were conserved molecules among these Theileria species, and the genes that encode p33/34 proteins were suitable for discrimination of T. sergenti from T. buffeli/T. orientalis.