特徴

• 背景：MHC class I chain-related molecules A （MICA） is one of the genes in the HLA class I region, which belongs to the MHC class I family.
• It is the member of the non-classical class I family that displays the greatest degree of polymorphism.
• The MICA protein product is expressed on the cell surface, although unlike canonical class I molecules do not seem to associate with beta-2-microglobulin.
• It is thought that MICA functions as a stress-induced antigen that is broadly recognized by NK cells, NKT cells, and most of the subtypes of T cells.
• The Natural killer group 2D （NKG2D）, a C-type lectin-like activating immunoreceptor, is a receptor of MICA, which was detected on most gamma-delta T cells, CD8+ alpha-beta T cells, and natural killer （NK） cells.
• Effector cells from all these subsets could be stimulated by the ligation of NKG2D.
• Engagement of NKG2D activated cytolytic responses of gamma-delta T cells and NK cells against transfectants and epithelial tumor cells expressing MICA.
• The MICA system is a novel, avidin-free immunohistochemical detection system that provides a significant increase in sensitivity compared to traditional immunodetection systems.