[Effect of immunization with tularemia vaccine on 3,4-benz[a]pyrene-induced blastomogenesis and mutagenesis in rats].

The living tularemia vaccine is studied for its effect on rat tumours and chromosome aberrations in bone marrow cells during 3,4-benz(a)pyrene injection (BP). It is established that a single epicutaneous vaccination of rats decreases the incidence of BP-induced tumours, prolongs the latent period and reduces the mean weight of tumours as well as lowers the number of myelocaryocytes with chromosome aberrations when BP is administered 15 days after immunization. 125 days after a single subcutaneous injection of BP in a dose of 4 mg the tumours appeared in 57% of animals and in 35% of preliminarily immunized animals. 24 h after intraperitoneal administration of 4 mg of BP the immunized rats revealed a 35% decrease in the amount of chromosome aberrations in myelocaryocytes as compared to the nonimmunized rats.