The LLT1 receptor induces IFN-γ production by human natural killer cells

• Published in: Molecular immunology Vol. 40; no. 16; pp. 1157 - 1163
• Main Authors: Mathew, Porunelloor A., Chuang, Samuel S., Vaidya, Swapnil V., Kumaresan, Pappanaicken R., Boles, Kent S., Pham, Hoang-Tuan K.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2004
• Subjects: Antibodies, Monoclonal - metabolism; Cell Line, Tumor; Cytotoxicity Tests, Immunologic; Dimerization; Dose-Response Relationship, Immunologic; Human; Humans; Immune regulation; Interferon-gamma - biosynthesis; Interferon-gamma - metabolism; Killer Cells, Natural - immunology; Killer Cells, Natural - metabolism; Lectins, C-Type - metabolism; Lectins, C-Type - physiology; LLT1; Lymphocyte Activation; Natural killer cells; Receptors, Cell Surface - metabolism; Receptors, Cell Surface - physiology; Human; Immune regulation; Natural killer cells; LLT1
• ISSN: 0161-5890; 1872-9142
• DOI: 10.1016/j.molimm.2003.11.024

Natural killer cell functions are regulated by signals through activating and inhibitory receptors. These receptors belong to the immunoglobulin superfamily or the lectin superfamily. We have previously identified a lectin-like transcript, LLT1, expressed in human NK cells. In the present study, we have generated a monoclonal antibody, L9.7, that specifically binds LLT1 receptor and studied the functional role of LLT1 in human NK cells. Binding of mAb L9.7 to surface LLT1 induced IFN-γ production, but did not modulate cytotoxicity by YT cells, a human NK cell line. We further demonstrate that in resting NK cells as well as in IL-2 activated NK cells LLT1 induced IFN-γ production, but not cytotoxicity. Excess amounts of L9.7 mAb failed to increase natural or antibody-dependent cell-mediated cytolytic activity, whereas minimal amounts achieved maximal production of IFN-γ by YT and activated NK cells. These findings further support the separation of signaling pathways that regulate cytotoxicity and IFN-γ production in resting as well as activated NK cells.