Natural Killer (NK) Cells: Origin, Recognition, Activation, and Functions

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Natural killer cells Dr Felix N. Toka Professor, Veterinary Immunology & Virology Department of Biomedical Sciences Objectives for this topic • Define the origin of Natural Killer (NK) cells and their role innate immunity • Understand the role of NK cell receptors in target cell recognition • Understand the killing mechanisms engaged by NK cells • Understand the regulatory role of NK cells in innate immune response Worldwide, a total of 372 clinical trials were undertaken in 2015/16 of which 10 were NK cell therapy trials Cell therapy: administration of living cells in humans with therapeutic purpose Natural cells (NK) • Originate from bone marrow • Live for about a week • Are found in the blood, spleen and liver • Migrate to tissues in large numbers only when an inflammatory reaction is underway • Do not posses receptors generated through gene segment rearrangement (i.e., no receptors such as TCR or BCR) Cell trafficking receptors on NK cells Cell trafficking receptors on NK cells Chemokine receptors • Also referred to as large granular lymphocytes (LGL), because morphologically, they resemble lymphocytes • They contain granules NK cell morphology NK cell identification in vitro •...