[HLA-G: immune tolerance in normal and pathological physiology].
HLA-G is a low polymorphic non-classical major histocompatibility complex class I molecule which can be expressed upon seven isoforms, and whose expression is correlated to immune tolerance situations. Indeed, the expression of HLA-G may allow partially or non histocompatible cells to escape host's immune aimed to eliminate these "foreign" cells. Functions share by HLA-G molecules are the ability to inhibit lysis mediated by natural killer (NK) and by cytotoxic T cells, and to induce apoptosis of activated CD8+ T cells via the HLA-G soluble form. Such model which evades defenses of the immune system was described in the foeto-maternal symbiosis, in tumoral cells or histo-incompatible graft previously. The importance of the role of HLA-G molecules expressed by particular cells as a shield against immune defenses is actually largely studied. The control of HLA-G expression could be used as immunotherapeutic approach, either by up-modulating HLA-G expression in order to favour tolerance of incompatible cells such as foetal cell or graft, or by down-modulating HLA-G expression in order to support the destruction of tumoral cells by cytotoxic T cells. This article reports the recent data on polymorphism, HLA-G gene transcription and implication of HLA-G molecules in immune responses during pregnancy, transplantation or tumoral growth.
Le Discorde
M
M
Service de recherches en hémato-immunologie, CEA, DSV/DRM, hôpital Saint-Louis, institut d'hématologie, 1, avenue Claude Vellefaux, 75475 Paris, France.
Moreau
P
P
Rouas-Freiss
N
N
Carosella
E
E
D018414:CD8-Positive T-Lymphocytes / Q000382:microbiology; D006680:HLA Antigens / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D006801:Humans; D007108:Immune Tolerance; D007167:Immunotherapy; D012016:Reference Values
D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I