Antigen presenting cells (APCs), especially dendritic cells (DCs), play a major role in the hierarchy of the induction of immune reactions. DCs are widely accepted as the most potent APCs capable of inducing protective adaptive immune responses in addition to tolerance to self-antigens. The role of DCs is currently being investigated in the context of many disease and therapeutic settings. In response to a variety of danger stimuli, resting DCs in peripheral tissues undergo a complex maturation process that might involve the regulation of genes that control distinct DC functions. The different functional properties of DCs are also linked to the existence of several subpopulations in humans and animals that differ in response to stimuli. On the other hand, immune reactions can be controlled by the so-called regulatory T cells that can interact with APCs such as DCs. Two main types of regulatory T cells have been identified (natural and induced) and both play significant roles in tuning down effector immune responses. Indeed, in parallel to thymus-derived natural Treg cells, induced regulatory T (iTreg) cells can develop in peripheral tissue under a variety of conditions such as antigen presentation under subimmunogenic or non inflammatory conditions. DCs and Treg cells are currently being considered as attractive targets towards manipulation of the immune system for therapeutic purposes. With this background, the special interest of our group is focusing on the immunobiology of tolerogenic DCs and Treg cells and their suppressive functions. We are studying more particularly the beneficial effect of DCs and/or Tregs in experimental models of arthritis. More recently, we focused our work on the characterization of the immune cells in the inflammatory environment, particularly in the synovial fluid from Rheumatoid Arthritis (RA) and Juvenile idiopathic Arthritis (JIA) patients. Our aims are:

1. Development of novel and effective immunotherapeutic tools in Rheumatoid Arthritis
2. Elucidating the role of DCs and/or regulatory cells in physiological and pathological conditions.
3. Identifying biomarkers of response to biotherapies.

Main achievements:

1. Immune tolerance induction using DC vaccination or adoptive Treg cell therapy
   https://doi.org/10.4049/JIMMUNOL.1501069
   https://doi.org/10.1186/AR4567
2. Induction of Treg cells in patients treated by biotherapies
   https://doi.org/10.1002/ART.38246
   https://doi.org/10.7150/THNO.27674
3. Characterization of Myeloid cells in synovial fluid from JIA patients
   https://www.frontiersin.org/articles/10.3389/fimmu.2020.01716/full