Immune cells (General immunomodulation via paracrine factors and cell-cell contact)

Immune cells (General immunomodulation) refers to the physiological process by which specific cell populations, such as mesenchymal stem cells (MSCs) or regulatory T cells (Tregs), orchestrate the immune response through secreted factors and direct physical contact (Kyurkchiev et al., 2014; Gao et al., 2016). Paracrine modulation involves the release of soluble mediators like IL-10, TGF-beta, and indoleamine 2,3-dioxygenase (IDO), which suppress effector cell proliferation and promote a tolerogenic environment (Uccelli et al., 2008). Simultaneously, cell-cell contact-mediated modulation occurs through the engagement of inhibitory receptors, such as PD-1 or CTLA-4, which provide essential off signals to activated lymphocytes (Abbas et al., 2021). This dual mechanism is vital for maintaining self-tolerance and limiting tissue damage during chronic inflammation. In drug development, this concept is frequently associated with cell-based therapies or broad-acting immunomodulators that aim to restore immune balance rather than targeting a single molecular pathway. Because it encompasses a wide array of cellular interactions and signaling molecules, it is characterized as a biological mechanism rather than a discrete molecular target (Gao et al., 2016).

Other names

Immunomodulatory cellsParacrine immune regulationCell-contact mediated suppressionImmune system modulationCell-mediated immunomodulation

Modulation of immune activity through the secretion of paracrine mediators (e.g., cytokines, prostaglandins) and direct cell-surface ligand-receptor interactions (e.g., checkpoint signaling) (Kyurkchiev et al., 2014; Abbas et al., 2021).