Assessment of immunogenicity and biological safety of protective antigen preparation obtained from asporogenic recombinant producer, B. anthracis 55ΔTPA-1(Spo-), is made on the mice (BALB/c species) and Guiney pigs models. It is shown that the development of adaptive immunity in the inoculated with purified protein laboratory animals is characterized by high titers of specific antibodies. Double immunization of biological models with antigen preparation confers protection from B. anthracis infection, commensurable with protective capacity of the live anthrax vaccine. Obtained are the data confirming the possibility to reduce the injected doze of the vaccine strain in case of subsequent single immunization with protective antigen. It is determined that recombinant protective antigen shows no sign of reactogenicity and does not damage thymocytes and splenocytes in laboratory animals when administered for immunization.