An ultrastructural study of heterokaryons derived from Theileria parva-infected bovine lymphoblasts and Ehrlich ascites tumour cells.

An ultrastructural study was made of Sendai virus induced heterokaryons derived from Theileria parva-infected lymphoblasts and Ehrlich ascites tumour cells. When fusion occurred, parasites were successfully integrated into the cytoplasm of the resulting heterokaryons where they appeared as morphologically normal macroschizonts. Homokaryon formation was also noted. This occurred frequently between Ehrlich ascites tumour cells and rarely with lymphoblasts. A small proportion of heterokaryons contained altered forms of T parva showing nuclear components, vesicular structures and paired organelles similar to the microshizont stage of the parasite.