Natural Mechanisms that Underlie the Defense of Host Organisms against Infections

Abstract

The topic of human–microbe interactions is of unfading relevance. Which interactions take place? Are microbes of any use, or are they essentially harmful? As the years go by, new microbiological techniques emerge, new facts on the coexistence of microbes and humans are revealed, and a new understanding of the coexistence of humans and microbes emerges. Mechanisms that underlie the natural protection of the host organism from infections are addressed in this article. The three interconnected components of the defense system considered here are the hypothalamic-pituitary system, oxytocin, and the microbiota. At first glance, these structures appear independent: the human brain contains the central “control panel” that regulates behavior, decision-making, and health. It regulates the functions of the major vitally important organs through the production of the neurohormone oxytocin, and recent studies revealed the contribution of the gut microflora (microbiota) to this regulation. Thus, the circle is closed. One can then ask whether microbes really control us. Let us address this question.