A Systematic Review on Crosstalk Between Microbiome and Immune System

The microbiome includes a diverse group of microorganisms that inhabit a particular niche. The microbes that inhabit humans and exhibit beneficial or symbiotic association are termed as normal flora, most of which secrete metabolites like vitamins and other growth factors which supplement the basic nutritional requirements for the body. The interspecies balance that is observed among the diverse groups of microbes is termed eubiosis and any deviation from this state is termed dysbiosis. It was hypothesized that there exists a crosstalk between the immune system and the microbiome of the host. These organisms play an important role in the induction and education of immune cells. This bilateral interaction plays a crucial role in maintaining human health by striking a fine balance between tolerances exhibited to normal flora and evoking responses against invading pathogens. Recent studies on the discovery of Pattern recognition receptors (PRRs), Toll-like receptors (TLRs), C-type lectin receptors, etc. expressed by a variety of cells are known to play a central role in immune surveillance mechanisms and are involved in maintaining homeostasis between the microbiome and immune responses. Many studies have proven that disruption of this balance paves the way for the development of pathogenesis in many disease conditions like allergy, autoimmune disorders, asthma, etc. The present review highlights the role of the human microbiome and its interaction with the immune system concerning its beneficial aspects and disease pathogenesis.