Mucosal and systemic immune system

The mucosal and systemic immune systems represent the integrated network of lymphoid tissues and cells responsible for host defense. The mucosal immune system is the largest component, protecting barrier surfaces like the gastrointestinal and respiratory tracts through specialized structures like Peyer's patches and the production of secretory IgA (Brandtzaeg, P. 'Mucosal immunity: induction, effector functions, and control', 2011). The systemic immune system, centered in the spleen and lymph nodes, provides internal surveillance and responds to pathogens that have entered the bloodstream or tissues (Mowat, A. M., & Agace, W. W. 'Regional specialization of the mucosal immune system', 2014). These systems are functionally linked but maintain distinct regulatory mechanisms to prevent overreaction to harmless antigens while ensuring robust responses to pathogens. Because this term describes a complex physiological system rather than a single protein or receptor, it is not classified as a specific therapeutic target in drug discovery (Janeway, C. A. Jr, et al. 'Immunobiology: The Immune System in Health and Disease', 2001).

Other names

Mucosal immunitySystemic immunityHost immune systemIntegrated immune systemMucosa-associated lymphoid tissue (MALT)Secondary lymphoid organs

Broad immunomodulation including cytokine inhibition, lymphocyte depletion, blockade of costimulatory signals, and checkpoint inhibition.