Human Killer Cell Immunoglobulin Like Receptor 3DL1 (KIR3DL1) Protein

Background

Killer Cell Immunoglobulin-Like Receptor 3DL1 (KIR3DL1) is a member of the KIR family, expressed on natural killer (NK) cells and a subset of T lymphocytes, playing a critical role in modulating immune responses. This receptor binds specifically to HLA class I molecules, particularly HLA-B alleles with the Bw4 motif, allowing NK cells to recognize and monitor the health of target cells. When KIR3DL1 engages its ligand, it delivers inhibitory signals that suppress NK cell cytotoxic activity, thus maintaining immune homeostasis and preventing autoreactivity. Variations in KIR3DL1, including polymorphisms and expression levels, are associated with differential susceptibility to infectious diseases, cancer, and autoimmune conditions. Studies have also highlighted its significance in allogeneic hematopoietic stem cell transplantation, where KIR-HLA mismatches can influence graft-versus-leukemia effects and transplantation outcomes. By regulating NK cell activity, KIR3DL1 contributes to the delicate balance between immune surveillance and tolerance, making it a valuable target for therapeutic interventions in cancer immunotherapy and immune-mediated disorders.