Adaptive Strategies of Pathogen–Host Interrelationships under Infection

Abstract

Interrelationships between microbes and the human organism have turned out to be not as simple as had been expected. This perception is evidenced by the long dispute between I.I. Mechnikov and R. Koch about the physiological mechanisms of host protection: the cellular component or humoral factors? Although this discussion is filed as history and the Nobel Prize was divided between these scientists for the creation of the cellular–humoral theory of immunity at the beginning of the 20th century, science has unveiled new riddles of Nature that may be called adaptive strategies of the “host–parasite” interrelationship. The driving forces of the infection process are considered: the agent of disease (microbe) and the host organism (humans, animals), i.e., the platform on which the disease progresses and the external environment (ecological factor) that changes the arrangement of participants in this interrelationship, and consequently, the outcome of the infection. This article shows examples and discusses the meanings of adaptive strategies for specific participants in the above process. The meaning of the persistent potential of microbes (both “self” and “nonself”) in interrelationships with the host is reflected. Applied aspects of the population organization and communication–related trend in microbiology and medicine are shown. New data are presented about the physiology of the key microbial regulator of homeostasis of the human intestinal biotope, the Bifidobacterium flora, or bifid flora, the main “conductor” of our health and a key figure among health-saving technologies under development.