Arnaud Pommier

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Work over the last decades has led to the identification of the factors that influence the survival and homeostasis of conventional T cells. IL-7 and TCR signaling promote the survival of naive CD4(+) and CD8(+) T cells in lymphoreplete mice and their proliferation in a lymphopenic environment, whereas survival and homeostatic proliferation of memory CD4(+)(More)
The present study evaluates the impact of immune cell populations on metastatic development in a model of spontaneous melanoma [mice expressing the human RET oncogene under the control of the metallothionein promoter (MT/ret mice)]. In this model, cancer cells disseminate early but remain dormant for several weeks. Then, MT/ret mice develop cutaneous(More)
Upon activation, naive CD4 T cells differentiate into a variety of T-helper-cell subsets characterized by different cytokine production and functions. Currently, lineage commitment is considered to depend mostly on the environmental context to which naive CD4 T cells are exposed. Here we challenge this model based on the supposed homogeneity of the naive(More)
In the periphery, Foxp3 expression is considered sufficient to maintain natural regulatory CD4(+) T-cell suppressive function. In this study, we challenge this model. Indeed, in mouse chimeras in which major histocompatibility complex (MHC) class II expression is restricted to the thymus, peripheral regulatory CD4(+) T cells lack suppressive activity. In(More)
Tumors affect myelopoeisis and induce the expansion of myeloid cells with immunosuppressive activity. In the MT/ret model of spontaneous metastatic melanoma, myeloid cells are the most abundant tumor infiltrating hematopoietic population and their proportion is highest in the most aggressive cutaneous metastasis. Our data suggest that the tumor(More)
CD4 regulatory T cells (Tregs) can be subdivided into two subsets according to Ly-6C expression in the periphery. Phenotypic analysis, imaging, and adoptive-transfer experiments of peripheral Ly-6C(-) and Ly-6C(+) Tregs reveal that the nonexpression of Ly-6C by ∼70% of peripheral Tregs depends on TCR signaling events. Interestingly, Ly-6C(-) Tregs express(More)
In recent years, broad classes of cells derived from the mononuclear phagocytic lineage, including myeloid-derived suppressor cells and tumor-associated macrophages, have been intensively investigated and found to promote the growth and metastatic dissemination of malignant cells. Conversely, the potential antineoplastic activity of monocytic cells has been(More)
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