DX5+CD4+T cells modulate CD4+T-cell response via inhibition of IL-12 production by DCs

Pathophysiology and treatment of rheumatic disease

IMMUNOSUPPRESSIVE DX5+T CELLS ARE POTENT INHIBITORS OF TH-1 RESPONSES VIA MODULATION OF DCS

Pathophysiology and treatment of rheumatic disease

DX5(+) CD4(+) T cells modulate cytokine production by CD4(+) T cells towards IL-10 via the production of IL-4

CD4(+) Th cells play a critical role in orchestrating the adaptive immune response. Uncontrolled Th1 responses are implicated in the pathogenesis of autoimmune diseases. T cells with immune-modulatory properties are beneficial for inhibiting such inflammatory responses. Previously we demonstrated that repetitive injections of immature DC induce expansion of DX5(+)CD4(+) T cells, which upon adoptive transfer show potent regulatory properties in murine collagen-induced arthritis as well as in delayed-hypersensitivity models. However, their regulatory mechanism remains to be defined. Here, we analyzed the effect of DX5(+)CD4(+) T cells on other CD4(+) T cells in vitro. Although proliferation of naive CD4(+) T cells upon antigenic triggering was not altered in the presence of DX5(+)CD4(+) T cells, there was a striking difference in cytokine production. In the presence of DX5(+)CD4(+) T cells, an IL-10-producing CD4(+) T-cell response was induced instead of a predominant IFN-gamma-producing Th1 response. This modulation did not require cell-cell contact. Instead, IL-4 produced by DX5(+)CD4(+) T cells was primarily involved in the inhibition of IFN-gamma and promotion of IL-10 production by CD4(+) T cells. Together, our data indicate that DX5(+)CD4(+) T cells modulate the outcome of Th-responses by diverting Th1-induction into Th responses characterized by the production of IL-10.Pathophysiology and treatment of rheumatic disease

Adoptive transfer of IL-10-secreting CD4(+)CD49b(+) regulatory T cells suppresses ongoing arthritis

We have previously demonstrated, in the collagen-induced arthritis model (CIA), that repetitive injections of immature bone-marrow-derived dendritic cells (iDCs) induce the expansion of a population of CD4CD49b-expressing cells, and that their adoptive transfer results in protection against CIA in a prophylactic setting. However, the in vivo mechanism responsible for their expansion, as well as their therapeutic potential in established disease remains to be defined. In the present study, we show that expression of the MHC class II molecules on iDCs is required for their expansion thus identifying these cells as MHC class II-restricted T cells. Using adoptive transfer of Thy1.1 positive cells, it is shown that iDC-induced CD4(+)CD49b(+) T cells home to the lymph nodes draining the inflamed tissue. The high immunomodulatory potential of these cells was underscored following their adoptive transfer in a model of contact hypersensitivity. Finally, we assessed and compared the therapeutic potential of iDC-inducible CD4(+)CD49b(+) T cells with that of iDCs in established CIA. Repetitive injections of iDCs in arthritic mice failed to decrease the severity of established disease. In contrast however, a single injection of iDC-induced CD4(+)CD49b(+) T cells reversed clinical symptoms of arthritis and provided long-lasting protection. Together, our data indicate that iDC-induced CD4(+)CD49b(+) T cells are bona fide T regulatory cells with strong immunomodulatory properties that are not only able to prevent disease onset, but also to interfere with an ongoing inflammatory immune response. (C) 2009 Elsevier Ltd. All rights reserved.Pathophysiology and treatment of rheumatic disease

A6.5 Versatile polyion complex micelles for peptide and sirna vectorization to engineer tolerogenic dendritic cells

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