CD161/KLRB1 (Killer cell lectin-like receptor subfamily B member 1, also known as CLEC5B and NKR-P1A) is a type II transmembrane protein that is expressed on the majority of Natural Killer (NK) cells, NK T cells, and some T lymphocytes. CD161/KLRB1 is also expressed on Th17 cells, promotes their generation, and modulates their function. Engagement with its ligand lectin-like transcript 1 (LLT1) inhibits NK cell function, while LLT1 and CD161/KLRB1 interaction in the presence of a TCR signal enhances IFN-gamma production by T cells. There are several different CD161 isoforms in rodents and some function as activating receptors as well.
