[The gnotobiologic approach to the study of the body's non-specific resistance to infection]

A new methodological approach to the study of the organism resistance to infection with the use of experimental animals with controlled microflora (germfree and other categories of gnotobiotic animals) is considered. Characteristics of the state of natural resistance of germfree animals, revealing considerable defects of cellular and humoral protection mechanisms, are given. Findings of experimental studies into inflammation, phagocytosis and other reactions of nonspecific resistance in gnotobiotic animals, disclosing complex mechanisms of formation of these reactions under the influence of microflora, are presented. The etiological and pathogenetic role of the microbial factor in the development of infectious diseases and in the formation of mechanisms of protective reactions at various levels of integration of the organism are discussed. Conclusions concerning prospects of the gnotobiological approach in investigating the role of the microbic factor in pathology are set forth.