Role of the Microbiota in Immunity and inflammation Original paper
Researched by:
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Divine Aleru
ID
Divine Aleru
I am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
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Divine Aleru
Researched by:
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Divine Aleru
ID
Divine Aleru
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Divine Aleru
What was reviewed?
This review explored the integral role of the microbiota in the development, calibration, and regulation of the mammalian immune system. It focused on how commensal microbes influence both innate and adaptive immunity, discussing the symbiotic relationship between host and microbiota under normal and pathological conditions. The review synthesized findings on how microbial communities modulate immune responses locally, such as at mucosal surfaces, and systemically, highlighting their involvement in shaping immune tolerance, inflammatory responses, and susceptibility to diseases like autoimmune disorders and infections.
Who was reviewed?
The review concentrated on human and murine models to illustrate the microbiota’s effect on immunity. It analyzed how diverse microbial communities impact the immune system from early life to adulthood. The evidence spanned multiple anatomical sites, including the gastrointestinal tract, skin, lungs, and other barrier tissues, recognizing the microbiota’s pervasive presence and its critical influence on immune health across different host organisms.
What were the most important findings?
This review underscored the pivotal role of the microbiota in fine-tuning immune responses at both mucosal and systemic levels. Key findings include the discovery that commensal bacteria act as adjuvants, essential for robust Th1 and Th17 responses, and the identification of “keystone species” such as Segmented Filamentous Bacteria (SFB), which potently stimulate gut immunity by inducing IL-17 and IgA production. Importantly, the review highlighted the microbiota’s capacity to maintain immune homeostasis via mechanisms like the production of antimicrobial peptides, strengthening barrier defenses, and training innate immune cells for rapid pathogen response. It also detailed systemic effects, showing that antibiotics or germ-free conditions dampen immune defenses, not only locally but throughout the body, as seen in impaired antiviral responses and tumor control. Additionally, specific commensals like Barnesiella were noted for their protective effects against infections such as vancomycin-resistant Enterococcus and Clostridium difficile, further illustrating the therapeutic potential of microbiome-targeted interventions.
What are the greatest implications of this review?
The findings presented have profound clinical and research implications. They emphasize that disturbances in microbiota composition, due to antibiotics, diet, or other factors, can trigger or exacerbate immune-related diseases, including allergies, autoimmune disorders, and chronic inflammation. The review suggests that microbiota manipulation, through probiotics, fecal microbiota transplants, or diet, offers promising therapeutic avenues for restoring immune balance. It also posits that understanding keystone microbes and their immune-modulating capabilities could revolutionize strategies for vaccine development, cancer immunotherapy, and infection control