Gut-Immune Interplay: Decoding the Microbiome's Impact on Immunity and Diseases

The gut microbiome is a critical regulator of local and systemic immunity with downstream consequences on immune functions and health of the host. Coevolution with the host bolsters the development and performance of the immune system, particularly during early life, and also plays roles in immune responses in adulthood. Alterations in the gut microbiome, whether as a result of antibiotics, diet, or environmental manipulation, can also drive inappropriate immune responses and predisposition to infections and inflammatory and autoimmune diseases. Since the microbiome impacts systemic immunity, microbial products stemming from the gut can alter immunity in far-flung tissues. Recent studies have emphasized the therapeutic promise of probiotics due to their ability to modulate gut microbiota and improve immune system activity and symptoms as well as prognosis of different diseases. Aging is one of the key risk factors for several age-related conditions, where the immune system and gut microbiome are major culprits, further explaining the importance of microbiome health across the life course. This emerging approach of microbiome modulation is opening up new pathways for combating infectious diseases, including both antibiotic-resistant infections and viral disease. This review highlights the interdependent nature of the gut microbiome and immune health, with significant ramifications for disease prevention and treatment.