Natural killer cell activating receptors (NKRs) (NKRs)

Natural killer (NK) cell receptors involved in BCG/PPD-induced activation refer to a functional group of surface proteins that mediate the immune system's response to Mycobacterium bovis Bacillus Calmette-Guérin (BCG) and Purified Protein Derivative (PPD). This group primarily includes activating receptors such as NKG2D and the natural cytotoxicity receptors (NCRs) NKp30, NKp44, and NKp46 (Biot et al., 2012, Journal of Innate Immunity). These receptors allow NK cells to recognize and eliminate BCG-infected cells or tumor cells, a process that is central to the efficacy of BCG immunotherapy in treating bladder cancer (Brandau et al., 2001, International Journal of Cancer). Activation is often a multi-step process involving direct recognition of mycobacterial ligands and stimulation by cytokines like IL-12 and IL-18 released by macrophages (Narni-Mancinelli et al., 2011, PNAS). In therapeutic contexts, these receptors are critical for the anti-tumor bystander effect where NK cells target malignant cells following BCG administration. Monitoring the expression and activity of these receptors serves as a key indicator of the potency of the innate immune response during mycobacterial-based treatments (UniProt Consortium, 2023).

Other names

Natural killer cell receptors involved in BCG/PPD-induced activationActivating NK cell receptorsNatural cytotoxicity receptorsNCRsNKG2DNKp46NKp44NKp30

BCG and PPD induce NK cell activation through direct receptor binding (e.g., NKp44) and indirect cytokine-mediated signaling (IL-12, IL-18) from accessory cells, leading to increased expression of activating receptors and enhanced cytotoxic activity (Brandau et al., 2001; Biot et al., 2012).