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Human cytomegalovirus, MHC class I and inhibitory signalling receptors: more questions than answers
Author(s) -
Cosman David,
Fanger Neil,
Borges Luis
Publication year - 1999
Publication title -
immunological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.839
H-Index - 223
eISSN - 1600-065X
pISSN - 0105-2896
DOI - 10.1111/j.1600-065x.1999.tb01292.x
Subject(s) - biology , immunoglobulin superfamily , receptor , microbiology and biotechnology , mhc class i , major histocompatibility complex , human leukocyte antigen , antigen , immunology , genetics
Summary: The human cytomegalovirus UL18 protein, an MHC class I homologue, has been shown to bind to leucocyte immunoglobulin‐like receptor (LIR)‐1, a member of a family of nine closely related immunoglobulin superfamily receptors expressed on leucocytes. The LIRs are related to the natural killer (NK)‐cell immunoglobulin‐like receptors and to several other immunoreceptors. Three groups of LIR molecules have been defined: those containing cytoplasmic domain inhibitory signalling motifs, those with short cytoplasmic domains and a charged residue within the trans‐membrane domain, and a secreted molecule. LIR‐1 and LIR‐2 bind to a broad spectrum of cellular MHC class I antigens, including HLA‐A, ‐B and ‐C alleles, LIR‐2 is expressed by all monocytes and dendritic cells, whereas LIR‐1 is additionally expressed by B cells and subsets of T and NK cells. Upon tyrosine phosphorylation, LIR‐ 1 and LIR‐2 associate with the tyrosine phosphatase, SHP‐1, and have been shown to inhibit FcγRI signalling when co‐crosslinked in monocytes. Evidence for and against a role of UL18 as ail inhibitor of NK‐cell function is discussed, as are possible functional outcomes of UL18‐LIR‐1 interactions in monocytic cells.