The general objectives of the Old Herborn University Foundation are the promotion of science and research. One particular aim are microbiota and the microbiome. What are microbiota? Microbiota are composed of microorganisms. Microbes reside in and on multicellular organisms and form an ecological community named microbiota. These include bacteria, archaea, protists, fungi and viruses. The term microbiome describes the whole genome of microorganisms assembled in microbiota. In todays common usage, however, the perceptions of microbiota and microbiome became more or less synonymous. During evolution in millions of years, microbiota and host emerged as a functional unit representing a “superorganism” or holobiont, a concept most important for human beings. Consequently, the specific objective of the Foundation is the focus on research into host-microbiota interaction for the benefit of human health. Humans coexist with myriads of microbes in most parts of their body, like the skin, the mouth, the gastrointestinal tract, the vagina, and even the lung and other parts as the placenta, hitherto considered to be sterile. Microbial cells outnumber human cells by a factor of ten to one hundred.

Intensive studies of metazoan and human physiology and its metabolic, immune and other functions reveal that many functions are deeply influenced by symbiotic microbial communities and even brain and behaviour are affected. The gut brain axis links gut and brain activities in a bi-directional communication system utilizing neural, endocrine and immunological signaling. A new comprehension of immune functions emerged and the immune system now appears not only as a defensive system, but also as an institution organising the communication between multicellular organisms and microbes.

In the past few years, a revolution occurred in life sciences regarding the understanding of host-microbial interaction indicated by fundamental shifts based upon the discovery of pattern recognition receptors in the innate immune system and the culture independent classification of the microbiome. Special molecular structures enable the crosstalk between innate immunity and the microbiome. The innate immune system literally senses microorganisms or their metabolites and translates key signals into host responses and the regulation of microbiota ecology. This communication illustrates the integration of microbiota into whole-body physiology and thus supports the holobiont concept. Microbes play a decisive role in metazoan existence. Coevolution of microbiota and host resulted in symbiosis. In this comprehension, man and microbes are partners in a complex interaction crucial for human health.

The exponentially rising number of publications on the topic „microbiota and man“ indicates the growth of appreciation of a new image of man and microbes as a functional unity and its role of intimate partners in a symbiotic system. Surprising insights into this complex ecological network let familiar paradigms falter and offer new routes in adaptive control of numerous interdependent physiological processes at multiple interfaces leading to an understanding of established concepts in therapeutic and preventive intervention, the promise of better targeted research and options for new clinical applications. The need for such action is highlighted in the launch of a National Microbiome Initiative of the US White House in May 2016 to support research on the microorganisms that live in or on the human body, plants and other ecosystems, to provide a better understanding of their role in human and environmental health.

Based upon these developments in life sciences, special attention is focused upon microbes as preventive and therapeutic agents in modulation of immune and other physiological functions, thus illustrating the most relevant activities of the Old Herborn University Foundation in search for insight and understanding of host-microbiota interaction. Consequently, experts from all over the world get together in the Old Herborn University Seminar series since 1987, lecture, discuss, and frame the findings to be published in the series of Old Herborn University Monographs to inspire fellow scientists and the medical community.