The facultative intracellular pathogen Listeria monocytogenes is a causative agent of the sapronotic diseases. Listerias, causing a serious illness in the man and a wide range of domestic and wild mammals, are facultative intracellular par-asites. InlB is an invasion factor interacting with a conservative eucaryotic receptor with-Met is the cause of active invasion of listeria in epitelial cells. Earlier, investigating L. monocytogenes strains al-located from clinical cases of listeriosis and from wild animals we identified 16 natural InlB options. Within this work we cloned 4 alleles inlB coding the most often meeting InlB options. The cloned alleles of inlB were injected into the strain of L. monocytogenes EGDeΔinlB deprived of this gene owing to the site, i.e. a specific deletion. 4 isogene recombinant strains differing only in se-quence of InlB were received as a result. Compari-son of an invasion efficiency of recombinant bacte-ria in cultures of epithelial cells of the person of HEK293 and a mouse of C26 showed that though all studied InlB options provided invasion in cells of both types, the efficiency of invasion was different. The variants providing more effective invasion in cells of the person were less effective in cells of mice and vice versa, the InlB variant providing max-imum efficiency of an invasion in cells of mice was less effective on human cells. The allele that gave rise to the most effective invasion in mouse cells was less efficient than other alleles in human cells. The strain demonstrating maximal invasion was more virulent on the mouse model of infection. Taken together, our data demonstrated that while all naturally occurred, InlB variants supported inva-sion in cells of both human beings and mice, some variants seemed to allow better invasion in cells of a certain host. Obtained results might be useful for understanding molecular mechanisms underlying polypathogenecity of sapronotic infectious agents and development of systems for L. monocytogenes control and monitoring.