Inflammation, generally perceived through a pathological lens, has now emerged as a crucial and highly efficient defense mechanism. Researchers from the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences (CAS) have discussed the evolutionary importance of inflammation, its dual role in preventing and curing diseases, and its future prospects in immunopreventive and immunotherapeutic strategies. 

The editorial article was published in The Innovation Life on Sept. 15.

Inflammatory responses are instrumental in upholding physical and functional integrity, often operating without conspicuous symptoms. They are initiated when foreign agents breach the body's protective barriers, culminating in the identification, phagocytosis, and elimination of the invaders. Pathological inflammation only manifests when the initiating agent cannot be eradicated or when the immune system falters, as exemplified by autoimmune disorders, chronic inflammatory diseases, allergies, and severe cytokine storms. 

Inflammation plays a pivotal role in augmenting the efficacy of vaccines. Adjuvants are substances that induce a controlled inflammatory response at the vaccination site, amplifying the protective immune reaction. Adjuvants like alum and oil-in-water emulsions activate macrophages, phagocytosis, and the inflammasome, resulting in the production of inflammatory cytokines such as IL-1β. IL-1β serves as the bridge connecting inflammation to adaptive immunity, thereby bolstering the immune response and fostering enduring protection against vaccine antigens. 

Within the context of tumor development, inflammation assumes a dual role. The tumor microenvironment (TME) can promote tumor growth by pushing tumor-associated macrophages (TAMs) to adopt a pro-healing phenotype. Therapeutic endeavors aim to modulate the TME, redirecting TAMs towards a cancer cell-killing role. In this regard, innate immune checkpoints and immunotherapeutic strategies targeting macrophage activation are currently under investigation. 

The use of inflammation for treating cancer traces its roots back over 3,000 years. Ancient Egyptian and Roman physicians harnessed infections to combat tumors. This practice evolved into bacterial-based immunotherapy, exemplified by Coley's toxin, which continues to find applications in certain cancer treatments today. Bacillus Calmette-Guerin, a tuberculosis vaccine made of live bacteria, activates macrophages for tumoricidal activities and can evoke innate memory, offering promising avenues for anti-cancer immunotherapy.

Inflammation retains its formidable status as a protective immune mechanism. Advances in comprehending its development and regulation empower us to harness its potential for effective immunopreventive and immunotherapeutic purposes, while mitigating adverse outcomes.