Biomedical subjects

Christelle Retiere

Publications and source records attributed to Christelle Retiere.

4 recordsLinked to original sources

PubMed2005

Cutting edge: lectin-like transcript 1 is a ligand for the CD161 receptor.

Human NK cells and subsets of T cells or NKT cells express the orphan C-type lectin receptor CD161 (NKR-P1A) of unknown function. In contrast to rodents that possess several NKR-P1 genes coding for either activating or inhibitory receptors, the nature of signals delivered by the single human NKR-P1A receptor is still to be clarified. In this article, we show that the lectin-like transcript 1 (LLT1) molecule is a ligand for the CD161 receptor. Engagement of CD161 on NK cells with LLT1 expressed on target cells inhibited NK cell-mediated cytotoxicity and IFN-gamma secretion. Conversely, LLT1/CD161 interaction in the presence of a TCR signal enhanced IFN-gamma production by T cells. These findings identify a novel ligand/receptor pair that differentially regulate NK and T cell functions.

Antigens, Surface↗

PubMed2003

The T cell surface--how well do we know it?

The overall degree of complexity of the T cell surface has been unclear, constraining our understanding of its biology. Using global gene expression analysis, we show that 111 of 374 genes encoding well-characterized leukocyte surface antigens are expressed by a resting cytotoxic T cell. Unexpectedly, of 97 stringently defined, T cell-specific transcripts with unknown functions that we identify, none encode proteins with the modular architecture characteristic of 80% of leukocyte surface antigens. Only two encode proteins with membrane topologies found exclusively in cell surface molecules. Our analysis indicates that the cell type-specific composition of the resting CD8+ T cell surface is now largely defined, providing an insight into the overall compositional complexity of the mammalian cell surface and a framework for formulating systematic models of T cell surface-dependent processes, such as T cell receptor triggering.

Antigens, Surface↗

PubMed2002

UL40-mediated NK evasion during productive infection with human cytomegalovirus.

Human cytomegalovirus (HCMV) exploits a range of strategies to evade and modulate the immune response. Its capacity to down-regulate MHC I expression was anticipated to render infected cells vulnerable to natural killer (NK) attack. Kinetic analysis revealed that during productive infection, HCMV strain AD169 first enhanced and then inhibited lysis of primary skin fibroblasts by a CD94/NKG2A(+)NKG2D(+)ILT2(+) NK line. The inhibition of cytotoxicity against strain AD169-infected fibroblasts was abolished by prior treatment of targets or effectors with anti-MHC I and anti-CD94 monoclonal antibodies, respectively, implying a CD94/HLA-E-dependent mechanism. An HCMV strain AD169, UL40 deletion mutant could not inhibit CD94/NKG2A(+) NK killing against skin fibroblasts. The contribution of UL40 to evasion of primary NK cells then was tested in a system where targets and effectors were MHC-matched. Primary NK cells activated with IFNalpha as well as cultured primary NK cell lines showed increased killing against DeltaUL40-infected fibroblasts compared with AD169-infected targets. This effect was abrogated by depletion of CD94(+) cells. These findings demonstrate that HCMV encodes a mechanism of evasion specifically targeted against a proportion of CD94(+) NK cells and show that this system functions during a productive infection.

Antibodies, Viral↗

PubMed2002

Cell-surface expression and immune receptor recognition of HLA-B27 homodimers.

OBJECTIVE: HLA-B27 is capable of forming in vitro a heavy-chain homodimer structure lacking beta(2)-microglobulin. We undertook this study to ascertain if patients with spondylarthritis express beta(2)-microglobulin-free HLA-B27 heavy chains in the form of homodimers and receptors for HLA-B27 homodimers. METHODS: Expression of HLA-B27 heavy chains by mononuclear cells was analyzed by fluorescence-activated cell sorter staining, Western blotting with the monoclonal antibody HC-10, and 2-dimensional isoelectric focusing. Fluorescence-labeled tetrameric complexes of HLA-B27 heavy-chain homodimers were constructed in which each dimer comprised one His-tagged heavy chain and one biotinylated heavy chain, and were used to stain patient and control mononuclear cells and transfected cell lines. RESULTS: Patients with spondylarthritis expressed cell-surface HLA-B27 homodimers. Populations of synovial and peripheral blood monocytes, and B and T lymphocytes from patients with spondylarthritis, and controls carried receptors for HLA-B27 homodimers. Experiments with transfected cell lines demonstrated that KIR3DL1 and KIR3DL2, and immunoglobulin-like transcript 4 (ILT4), but not ILT2, are receptors for HLA-B27 homodimers. CONCLUSION: Patients with spondylarthritis express both HLA-B27 heavy-chain homodimers and receptors for HLA-B27 homodimers. This may be of significance with regard to disease pathogenesis.

Adult↗