Innate immune cell receptors (Macrophages and Natural Killer cells)

Innate immune cell receptors on macrophages and natural killer (NK) cells comprise a diverse array of proteins that regulate the body's immediate response to pathogens and malignant cells. On macrophages, these include pattern recognition receptors (PRRs) like Toll-like receptors (TLRs) and phagocytic regulators such as the SIRPα receptor, which interacts with CD47 to prevent the engulfment of healthy cells (Willingham et al., 2012, PNAS). NK cells utilize a sophisticated balance of activating receptors, such as NKG2D and CD16, and inhibitory receptors, including Killer cell Immunoglobulin-like Receptors (KIRs) and NKG2A, to identify and eliminate stressed or transformed cells (Vivier et al., 2011, Science). These receptors are increasingly targeted in oncology as "innate checkpoints" to overcome tumor-mediated immune evasion. For example, blocking the inhibitory NKG2A receptor with monalizumab or the SIRPα-CD47 axis with magrolimab can restore the innate immune system's ability to attack cancer (André et al., 2018, Cell). Beyond cancer, these receptors are involved in chronic inflammatory conditions and infectious diseases, where they modulate the intensity of the immune response. Therapeutic strategies include monoclonal antibodies, bispecific engagers, and small molecule agonists designed to shift the immune microenvironment from suppressive to inflammatory. Therapeutic challenges include managing potential cytokine release syndrome and ensuring that the activation of innate cells does not lead to the destruction of healthy tissues expressing similar ligands.

Other names

Innate immune checkpointsPattern recognition receptorsNK cell activating and inhibitory receptorsMacrophage surface receptorsInnate immune cell surface proteins

Modulation of innate immune cell activity through activation of stimulatory receptors or blockade of inhibitory checkpoint receptors to enhance anti-tumor or anti-pathogen responses.