Ayala Tamir, PhD

The functional role of CD48 in different DC subsets and the link to autoimmunity
CD48 is an anchor protein of the CD2 superfamily and interacts with two receptors: CD2 and CD244 (2B4). The broad expression of CD48 may indicate that this molecule participates in immune regulation and it may therefore have a role in the induction of autoimmunity. Because dendritic cells (DCs) are key cells in balancing stimulation/tolerance of the immune response, we have been studying the link between CD48 expression on DCs and their immune function. Firstly, we have analyzed the expression of CD48 in different murine DC subsets derived from different organs. Our preliminary data show that CD48 expression on bone marrow and spleen-derived CD11c+ DCs was enhanced on maturing DCs as well as expression of CD205 and to a lower extent, CD2. Our data have also shown that bone-marrow derived DCs of CD48-/- mice but more of wild type mice, induced higher proliferation and IFN-g production from CD48-/- T cells compared with wild type-derived T cells, in the presence of an autoantigen-derived peptide. Even more significantly, IL-4 production from CD48-/- derived T cells exceeded the production from wild type-derived T cells. As plasmacytoid DCs are the most potent producers of IFN-a, a cytokine that has been linked to autoimmunity, levels of this cytokine production will be measured from wild type and CD48-/- mice, as well as levels of IL-10 and IL-12, to determine the type of immune response involved. In addition, the function DC-stimulated regulatory T cells derived from these two groups of mice will also be investigated. This study may highlight the link between CD48 and its expression on different DC subsets to autoimmunity, an area that has not been clearly addressed.

The possible effects of CD4+CD25+ regulatory T cells on immunosuppression in transfused cardiac surgery patients.