Protective effect of dendritic cells (DC) was studied in CBA mice infected by K. pneumoniae K2. Lipopolysaccharide K. pneumoniae, K. pneumoniae K₂ lysate and polycomponent vaccine Immunovak-VP-4 of conditionally pathogenic microorganisms were used as maturation inductors for DCs generated from murine bone marrow. Immature DCs, as well as mature cells, regardless the type of stimulating agent injected intraperitoneally demonstrated protective effect of 83.3 up to 100% in mice infected by K. pneumoniae (100LD50). DCs generate a range of cytokines that might activate complex mechanisms of inter-cellular relations. Immature protective DC activity against K. pneumoniae may be associated with the following induction of cytokine synthesis in vivo stimulated both by DCs and microorganism cells. The results of the study lead to a conclusion that DCs can have additional functions besides their high ability to stimulate proliferation of syngeneic mononuclear leukocytes that is due to DC involvement in reactions of inter-cellular interaction while non-specific immune response is being formed. Development of DC-based vaccines for adoptive immunotherapy suggests perspective way for prophylactics and therapy of infectious diseases.