Natural Killer (NK) cells are large granular lymphocytes of the innate immune system. They are widespread throughout the body, being present in both lymphoid organs and non-lymphoid peripheral tissues. NK cells are involved in direct innate immune reactions against viruses, bacteria, parasites and other triggers of pathology, such as malignant transformation, all of which cause stress in affected cells. Importantly, NK cells also link the innate and adaptive immune responses, contributing to the initiation of adaptive immune responses and executing adaptive responses using the CD16 FcgRIIIA immunoglobulin Fc receptor. Such responses are mediated through two major effector functions, the direct cytolysis of target cells and the production of cytokines and chemokines. The authors focus here on the nature of recognition events by NK cells and address how these events are integrated to trigger these distinct and graded effector functions.

Our understanding of the function of natural killer (NK) cells has dramatically changed in recent years. The discovery of NK receptors specific for MHC class I molecules, and the study of the role of co-stimulatory and adhesion molecules have led to an understanding of how NK cells recognize tumor and virally infected cells that have lost expression of MHC class I molecules or have altered distribution of normal cell surface molecules. Such recognition events lead to intracellular signals which can be either stimulatory or inhibitory. This book provides an insight into how NK cells develop, how they learn to distinguish altered cells from normal cells, and into their biological role in controlling infections and tumors.

Natural Killer (NK) cells are large granular lymphocytes of the innate immune system. They are widespread throughout the body, being present in both lymphoid organs and non-lymphoid peripheral tissues. NK cells are involved in direct innate immune reactions against viruses, bacteria, parasites and other triggers of pathology, such as malignant transformation, all of which cause stress in affected cells. Importantly, NK cells also link the innate and adaptive immune responses, contributing to the initiation of adaptive immune responses and executing adaptive responses using the CD16 FcgRIIIA immunoglobulin Fc receptor. Such responses are mediated through two major effector functions, the direct cytolysis of target cells and the production of cytokines and chemokines. The authors focus here on the nature of recognition events by NK cells and address how these events are integrated to trigger these distinct and graded effector functions.