Comparative analysis of infection and transformation of lymphocytes from African buffalo and Boran cattle with Theileria parva subsp. parva and T. parva subsp. lawrencei.

This study compared infection and transformation of peripheral blood mononuclear cells (PBM) of Boran cattle and African buffalo in vitro to determine whether differences occurred which could account for the greater susceptibility of Boran cattle to infection with Theileria parva subsp. parva and T. parva subsp. lawrencei. PBM from buffalo and cattle had a similar percentage of cells which bound T. parva subsp. parva sporozoites (24 to 34%) and in which schizonts developed during the first week after infection (18 to 23%). Using a limiting dilution culture system, it was established, however, that a significantly higher proportion of cattle PBM transformed into continuously replicating cell lines after infection with T. parva subsp. parva than did buffalo PBM. The evidence suggests that the low capacity of T. parva subsp. parva to establish infections in buffalo compared with cattle is related to the lower frequency of buffalo cells which undergo transformation. With T. parva subsp. lawrencei, however, the frequency of transformation of buffalo PBM was higher than that for cattle PBM. The frequency of cells transformed by T. parva subsp. lawrencei, therefore, cannot account for the greater resistance of buffalo to infections with T. parva subsp. lawrencei. Buffalo must have other mechanisms, either innate or acquired, which control infection with T. parva subsp. lawrencei more efficiently than in cattle.