Clec4b2, also known as mDCAR1, is a member of the DCIR/DCAR family. Expression of Clec4b2 was strongly tissue dependent. Clec4b2 expression on DCs was restricted to the CD8(+) DC subset in spleen and thymus and on subpopulations of CD11b(+) myeloid cells in bone marrow and spleen, whereas the molecule was not detectable on both cell types in lymph nodes and peripheral blood. Clec4b2 is a functional receptor on cells of the immune system and provides further insights into the regulation of immune responses by CLRs.