Human cytomegalovirus and natural killer-mediated surveillance of HLA class I expression: a paradigm of host-pathogen adaptation.
Among various strategies to evade the host immune response, some viruses like human cytomegalovirus (HCMV) interfere with surface MHC class I expression and antigen presentation to T lymphocytes. The ability of natural killer (NK) cells to detect MHC class I molecules through inhibitory receptors can be envisaged as an adaptation of the immune system for responding to such pathological alterations. To fulfil that role, rodents use members of the Ly49 C-type lectin superfamily, whereas primates employ killer immunoglobulin-like receptors and the immunoglobulin-like transcript 2/leucocyte immunoglobulin-like receptor-1 receptor. CD94/NKG2 lectin-like heterodimers represent the most conserved receptor system for MHC class I molecules; by interacting with human HLA-E or murine Qa-1b, CD94/NKG2A inhibitory receptors broadly probe the biosynthesis pathway of other class I molecules. Reciprocally, HCMV has developed mechanisms to evade the NK response while modulating HLA class Ia expression. The ability of HCMV to maintain surface levels of HLA-E and to express an HLA class I surrogate (UL18) are herein discussed in the context of the interplay with human NKR systems.
López-Botet
M
M
Universitat Pompeu Fabra, CEXS, Barcelona, Spain. miguel.lopez-botet@cexs.upf.es
Llano
M
M
Ortega
M
M
D000222:Adaptation, Physiological; D000818:Animals; D003587:Cytomegalovirus / Q000276:immunology* / Q000472:pathogenicity*; D006680:HLA Antigens / Q000378:metabolism*; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D051379:Mice; D011971:Receptors, Immunologic / Q000378:metabolism; D014764:Viral Proteins / Q000276:immunology; D000097625:HLA-E Antigens
D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D011971:Receptors, Immunologic; D014764:Viral Proteins; D000097625:HLA-E Antigens