DELIVERY OF THE THEILERIA-PARVA P67 ANTIGEN TO CATTLE USING RECOMBINANT VACCINIA VIRUS - IL-2 ENHANCES PROTECTION

To evaluate vaccinia virus as a delivery system for recombinant antige n in cattle, calves were immunized with a recombinant vaccinia virus ( rVV) expressing the sporozoite surface antigen (p67) of Theileria parv a (V-67) combined with those expressing bovine IL-4 (V-IL4) or IL-2 (V -IL2), The anti-p67 antibody levels detected in calves inoculated with the combination of V-67 and V-IL4 were higher than those produced by animals injected with V-67 alone or V-67 and V-IL2. On challenge with cryopreserved sporozoites, 5 of 7 animals receiving V-67 combined with V-IL2 were protected, while those receiving V-67 in conjunction with V-IL4 behaved like unimmunized control calves, Vaccination with a reco mbinant virus expressing a chimaeric p67(p583)/IL2 product gave rise t o a lower level of protection, whereas V-IL2 provided no immunity The results of this study demonstrate the potential of rVV as a delivery s ystem for use in vaccination of cattle against Theileria parva infecti on. (C) 1998 Elsevier Science Ltd All rights reserved.