Human Killer cell lectin-like receptor subfamily B member 1 (KLRB1) Protein

Background

Killer cell lectin-like receptor B1 (KLRB1), also known as CD161, is a type II transmembrane protein predominantly expressed on subsets of immune cells, especially natural killer (NK) cells and T cells. KLRB1 plays a key role in modulating immune responses and is especially involved in the regulation of cytotoxicity and cytokine production, particularly among NK and T cell subsets. KLRB1 belongs to the C-type lectin superfamily and is encoded by the KLRB1 gene located on chromosome 12p13 in humans. KLRB1’s expression is associated with an inhibitory effect on immune cell activation, helping maintain immune homeostasis, prevent excessive immune responses, and aid in the modulation of immune activity against infections, tumors, and in inflammatory diseases. KLRB1 is primarily known for its role as a receptor for the carbohydrate-bearing protein LLT1 (lectin-like transcript 1, or CLEC2D). This interaction facilitates cell-cell communication and can mediate inhibitory signaling in NK cells and some T cell subsets, potentially leading to immune tolerance in certain tissues and tumors.