Immunopharmacological aspects of studying immunotropic properties of a novel biocompound

The article presents an experimental study of immunotropic activity of a new compound, a metabiotic, based on metabolites (biologically active substances) produced by a of saprophytic Bacillus subtilis B-9909 strain, being safe for health and standardized at Russian National Collection of Industrial Microorganisms (RNCIM). The aim of our study was to experimentally evaluate the immunotropic effects of metabolites produced by the probiotic Bacillus subtilis B-9909 upon the parameters of cellular immunity tested in the animal model of induced toxic liver damage. The metabolites were isolated from the cultural liquid of Bacillus subtilis culture (RNCIM strain B-9909) during its deep cultivation in a medium containing hydrochloric acid hydrolyzate of soy flour, or pancreatic hydrolyzate of casein. At 16-18 hours of cultivation, the cells were in the exponential growth phase. The indices of cellular status were studied in experimental groups of animals, when assessing therapeutic efficacy of an experimental metabiotic sample, as compared to a group of laboratory animals treated with the reference drug (ursosan). We assessed the quantitative indicators of blood as follows: determination of phagocytic activity (FA) of peripheral blood neutrophils; measurement of metabolic activity in peripheral blood neutrophils by means of NBT-test; quantitative determination of T and B lymphocytes; the number of antibody-forming cells (AFC). Liver damage was studied in a model of acute toxic hepatitis in albino rats. Experimental toxic hepatitis was induced by 40% solution of CCl₄ in vaseline oil injected intragastrically for 2 weeks at the dose of 0.2 g/kg. The results of experimental studies showed activation of phagocytic activity by peripheral blood neutrophils at the early terms of experiment, being also confirmed by the results of NBT-testing. Moreover, at the early observation terms, a significantly increased representation of T and B lymphocyte populations as well as AFC numbers, were revealed thus suggesting activation of all components of cellular immunity in response to the carbon tetrachloride toxicity. Thus, the reported studies on the cellular status of laboratory animals treated with metabolites produced by probiotic microorganisms of the genus Bacillus subtilis (B-9909) on laboratory animals with toxic liver damage allow us to conclude that the test sample of this metabiotic preparation exerts a significant immunomodulatory effect, when compared with ursosan. This evidence allows us to consider this compound a promising candidate drug for a new hepatoprotector with immunotropic effect.