EN
FLK cells persistently infected with BLV were used for the preparation of two vaccines. One contained the formalin-fixed cells (FORM vaccine) and another the cells treated with glutaraldehyde (GLUT vaccine). The concentration, temperature and time of action of the fixatives were different. It was stated that the vaccine FORM elucited the formation of antibodies for the gp antigen of BLV which persisted in the serum not longer than 75 days. The prolongation of this time could be achieved by means of revaccination of animals or by injection of an appropriate dose of BLV. The resistance acquired due to the vaccination could be overcome by a large dose of BLV. Since, the vaccine had only a limited capacity to control the horizontal transmission of the virus, therefore, it could not be recommended for practical use. The vaccine GLUT proved to be ineffective. The effectiveness of the both preparations was compared with that one prepared previously from BLV treated with UV rays.