AN EFFECTIVE PEPTIDE VACCINE TO ELIMINATE BOVINE LEUKEMIA-VIRUS (BLV)INFESTED CELLS IN CARRIER SHEEP

Protective effects of the gp51 of bovine leukaemia virus (BLV) express ed by a recombinant baculovirus (rgp51) and synthetic multiple antigen ic peptides (MAP) of T-helper, T-cytotoxic, and B-cell epitopes of gp5 1 were investigated against BLV challenge. Two and three sheep were im munized with rgp51 and a mixture of peptides with Freund's complete ad juvant, respectively. BLV was detected from all the immunized sheep at 2 weeks and showed peak levels at 4 weeks after the challenge. Howeve r, in two sheep immunized with the mixed peptides, the titer of BLV gr adually decreased and one sheep eliminated BLV completely at 28 weeks after the challenge. These two sheep showed higher lymphocyte prolifer ative responses against the immunized peptides than the other sheep, O ne of the sheep also showed the specific cytotoxic lymphocyte activity against the BLVgp51-expressing target in vitro. These results suggest the possibility of the peptide vaccine for elimination of BLV in carr ier animals in vivo. Copyright (C) 1996 Elsevier Science Ltd.