Macrophages and innate immune cells

Macrophages and innate immune cells constitute the primary cellular defense mechanism of the host, responsible for the rapid detection and elimination of pathogens and cellular debris. These cells, which include monocytes, macrophages, neutrophils, and dendritic cells, utilize a diverse array of pattern recognition receptors to initiate inflammatory cascades and bridge the gap between innate and adaptive immunity (Janeway et al., 2001). In various pathologies, particularly cancer and chronic inflammatory disorders, these cells can adopt specialized phenotypes—such as M1 (pro-inflammatory) or M2 (anti-inflammatory/pro-tumor)—that significantly influence disease progression (Mantovani et al., 2017). While not a single molecular target, they are the focus of numerous therapeutic interventions aimed at modulating their activity, such as inhibiting the Colony-stimulating factor 1 receptor (CSF1R) to deplete tumor-associated macrophages or activating Toll-like receptors (TLRs) to stimulate anti-tumor responses (Coussens et al., 2013). Understanding the heterogeneity and plasticity of these cells is essential for developing precision immunotherapies that can selectively reprogram the immune microenvironment (StatPearls, 2023). Consequently, this entry represents a broad cellular category rather than a specific, druggable molecular entity.

Other names

Innate immune systemMyeloid cellsMononuclear phagocyte systemProfessional phagocytesInnate immune effectors

Therapeutic agents modulate these cells by targeting specific surface receptors (e.g., CSF1R, TLRs, CCR2) to induce depletion, inhibit recruitment, or stimulate phenotypic reprogramming from immunosuppressive to pro-inflammatory states.