NK Cell CD Proteins

The cluster of differentiation (CD) antigens a protocol used for the identification and investigation of cell surface molecules present on leukocytes. Some CD proteins often act as cell-cell or cell-matrix adhesion molecules, cytokine receptors, ion pores, or nutrient transporters. CD proteins play a variety of roles in immune system function. Natural killer (NK) cells are innate immune cells that show spontaneous cytolytic activity against cells under stress such as tumor cells and virus-infected cells. They are distinguished by their unique functions and expression of surface antigens. NK cells lack the clonotypic T cell receptor (TCR) of T and NKT cells and its associated signal-transducing adaptor, CD3ε. In humans, subsets of NK cells express the activating Fc receptor, CD16 and most express CD56 [neural cell adhesion molecule (NCAM) or Leu-19] . In C57BL/6 mice, NK cells are identified by the presence of NK1.1 (NKR-P1C) and NCR1 (NKp46/CD335), as well as CD49b (DX5, Integrin VLA-2α), are common NK cell markers in other mouse backgrounds.