Symbiotic microbiota: A class of potent immunomodulators

Microbiome is known to exist as symbiotic commensals in humans, domestic and wild animals, birds, fishes, reptiles, insects etc. DNA sequencing and metagenomic platforms have deciphered the complex role played by communities of microbiota (bacteria, fungi, viruses, protozoa and other eukaryotic species) in survival and regulation of host physiology, metabolism and regulation of host immune system. Any alteration in the microbial population or breach in the symbiotic alliance with the host may ultimately lead to development of different kinds of pathologies. Realization of the enormous role played by the microbiome in health and diseases of human and domestic livestock led researchers to find ways to modulate these resident microbiomes for improvement in health and management of diseases. Theoretically there are several ways that can be employed for manipulating the composition and functional capacity of the resident microbiome, which may lead to improvements in human and livestock health. Though studies have shown therapeutic potential of the microbiome, considerable challenges exist in the actual implementation of these strategies in clinical settings. This review discusses the symbiotic relationship between microbiome and host and strategies to modulate host immune responses by manipulating microbiome profile. Paper also highlights how to overcome existing obstacles for successful implementation of microbiome manipulation techniques. In this era of COVID-19, it would be worth analysing the role of resident microbiome in the magnitude of COVID-19 severity which may have occurred through immunomodulation.