Related Experiment Video
Updated: Aug 26, 2026

Measurement of Natural Killer Cell-Mediated Cytotoxicity and Migration in the Context of Hepatic Tumor Cells
Published on: February 22, 2020
Cis association of Ly49A with MHC class I restricts natural killer cell inhibition
Marie-Agnès Doucey1, Léonardo Scarpellino, Jacques Zimmer
1Institute of Biochemistry, University of Lausanne, Ch. des Boveresses 155, 1066 Epalinges, Switzerland.
Abstract:
Natural killer (NK) cell function is negatively regulated by inhibitory receptors interacting with major histocompatibility complex class I molecules expressed on target cells. Here we show that the inhibitory Ly49A NK cell receptor not only binds to its H-2D(d) ligand expressed on potential target cells (in trans) but also is constitutively associated with H-2D(d) in cis (on the same cell). Cis association and trans interaction occur through the same binding site. Consequently, cis association restricts the number of Ly49A receptors available for binding of H-2D(d) on target cells and reduces NK cell inhibition through Ly49A. By lowering the threshold at which NK cell activation exceeds NK cell inhibition, cis interaction allows optimal discrimination of normal and abnormal host cells.
Related Concept Videos
Cells of the Innate Immune Response
Phagocytes
Phagocytes police the peripheral tissues by removing cellular debris and responding to the invasion of foreign substances or pathogens. Many phagocytes attack and remove microorganisms even before lymphocytes detect them. The human body has two general...
Antigens Involved in Adaptive Immunity
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...
Immune Surveillance by NK Cells and Phagocytes
Natural Killer Cells: The Fast Responders
NK cells are large granular lymphocytes found in the blood and lymphatic system. These...
Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
