Adoptive transfer of immunity to infection with Theileria parva (East Coast fever) between cattle twins.

Resistance to a lethal challenge with Theileria parva (Muguga) was transferred between two pairs of chimeric bovine co-twins with 5 to 9 X 10(10) syngeneic thoracic duct leucocytes from the immunised partner. In one recipient, the infection became established and was eliminated. In the second recipient, the disease did not become patent. Both recipients were immune to a second challenge of T parva (Muguga). The results confirm both that chimeric twin calves are suitable as a model for the adoptive transfer of cell-mediated immunity in cattle and that recirculating lymphocytes confer resistance against infection with T parva to immune cattle.