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Role of paired Ig-like receptor-B in the humoral immune response


  • Toshiyuki Takai

    1. Department of Experimental Immunology and Core Research for Evolutional Science and Technology Program of the Japan Science and Technology Agency, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
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Toshiyuki Takai, Department of Experimental Immunology, Institute of Development, Aging and Cancer, Tohoku University, Seiryo 4-1, Sendai-city, Miyagi 980-8575, Japan. Email:


The Ig-like receptors provide positive and negative regulation of immune cells upon recognition of various ligands, thus enabling those cells to respond adequately to extrinsic stimuli. Murine paired Ig-like receptor (PIR)-A and PIR-B, a typical receptor pair of the Ig-like receptor family, are expressed on a wide range of cells in the immune system, such as B cells, mast cells, macrophages and dendritic cells, mostly in a pair-wise fashion. The PIR-A requires the homodimeric Fc receptor common γ chain for its efficient cell-surface expression and for the delivery of activation signaling. In contrast, PIR-B inhibits receptor-mediated activation signaling in vitro upon engagement with other activating-type receptors, such as the antigen receptor on B cells and the high-affinity Fc receptor for IgE on mast cells. Although the ligands for PIR-A and PIR-B remain unknown, recent studies on PIR-B-deficient mice have provided us with valuable insight into the physiological significance of PIR-B, particularly in its regulatory role in balancing the humoral immune response.