A major goal of Dr. Clark’s lab has been to define receptors and ligands regulating B cells and dendritic cells (DCs) and to help translate findings for use in clinical immunology. His lab helped discover and characterize human B cell/DC-associated surface molecules like CD20, CD22, CD40, CD80 (B7.1), CD150 (SLAM) and CD180 (RP105). Recently, the lab has focused on defining C-type lectin receptors (CLRs) on DCs including DCAL1, which binds to a ligand on CD4 T cells and promotes IL-4 production, and DCAL2, which is a useful marker to identify and isolate mouse DC subsets. In order to assess the function of CLRs and their possible use for vaccine development, Dr. Clark’s lab has coupled antigens (Ags) to monoclonal antibodies (mAbs) specific for CLRs expressed on DC subsets. The Ag-mAb conjugates are inoculated into mice as a kind of ‘antigen-delivery system’, which enables Ags to be selectively targeted to a particular DC subset, which then responses and programs an appropriate, protective immune response. Transgenic mice expressing human CLRs such as DCAL1 or BDCA2 have been made and are being used as preclinical vaccine models for assessing Ag-anti-human CLR conjugates in vivo.