Analyses of antigenic and genetic diversities of Theileria sergenti piroplasm surface proteins.

Monoclonal antibodies (MoAbs) against Theileria sergenti Fukushima stock, an intraerythrocytic protozoan parasite of cattle, were produced. The MoAbs reacted with 32 kDa or 23 kDa piroplasm surface protein (p32 or p23) in Western blot analysis. Using a panel of the MoAbs, antigenic analysis of the stocks and field isolates distributed in Japan was carried out. The results revealed antigenic diversity of T. sergenti isolates, but diversity did not appear to be correlated with the geographical region of the isolates. N-terminal amino acids sequences analysis revealed substitutions of a few amino acids between the p23 of two T. sergenti stocks. The sequences couldn't be found in amino acid sequence of the p32 deduced from cDNA, which indicated that the p23 is not a proteolytic product of the p32. Genetic diversity of T. sergenti isolates was also observed by Southern blot analysis using a cDNA of the p32 as a probe.