Modulation of HLA-G antigens expression in myelomonocytic cells.
As trophoblast cells and macrophages share cellular characteristics, we investigated the expression of HLA-G antigens during the myelomonocytic differentiation. Analyses with the 87G and 16G1 monoclonal antibodies demonstrated that HLA-G was not expressed in peripheral blood monocytes, in in vitro differentiated dendritic cells and macrophages, and in resident mononuclear phagocytes infiltrating healthy tissues. Conversely, activated macrophages and dendritic cells localized in tumoral biopsies of some lung carcinomas expressed HLA-G antigens. Induction of HLA-G expression at the cell surface of the monohistiocytic cell line U 937 with different cytokines strongly suggests that cytokines secreted during inflammation may be involved in this specific upregulation. Bronchoalveolar macrophages collected from patients suffering from acute HCMV pneumonitis also expressed HLA-G molecules. In vitro, we thus demonstrated that HLA-G antigens are produced during viral reactivation in the macrophages generated after allogeneic stimulation of HCMV latently infected monocytes. Our data suggest that inflammatory processes in lung tissues, like tumoral transformation and HCMV acute infection, are likely to induce HLA-G molecules in infiltrating macrophages and dendritic cells. The expression of molecules capable of downregulating both the innate and adoptive immunity could be a mechanism that helps tumoral and HCMV infected cells to escape immune response.
Onno
M
M
Laboratoire Universitaire d'Hématologie et de la Biologie des Cellules Sanguines, Faculté de Médecine, CRI INSERM 9606, Rennes, France. myriam.onno@univ-rennes1.fr
Le Friec
G
G
Pangault
C
C
Amiot
L
L
Guilloux
V
V
Drénou
B
B
Caulet-Maugendre
S
S
André
P
P
Fauchet
R
R
D000208:Acute Disease; D001706:Biopsy; D002277:Carcinoma / Q000276:immunology / Q000473:pathology; D002460:Cell Line; D016207:Cytokines / Q000494:pharmacology; D003713:Dendritic Cells / Q000276:immunology*; D005434:Flow Cytometry; D006680:HLA Antigens / Q000096:biosynthesis* / Q000276:immunology; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000276:immunology; D006801:Humans; D008168:Lung / Q000276:immunology / Q000473:pathology; D008175:Lung Neoplasms / Q000276:immunology / Q000473:pathology; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D009000:Monocytes / Q000187:drug effects / Q000276:immunology* / Q000821:virology; D011024:Pneumonia, Viral / Q000276:immunology; D020298:U937 Cells
D016207:Cytokines; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I