TGF-b signaling is indeed a known regulator of b-catenin signaling. In this report, we have exploited the BMDC model in order to explore the role of b-catenin signaling in tolerogenic DC activation as well as to address to what extent TGF-b influences b-catenin signaling and tolerogenic responses in DCs. We cultured immature bone marrow-derived dendritic cells to study mechanisms that may orchestrate tolerogenic DC maturation. We began our studies by reproducing aspects of this model reported previously. DC maturation encompasses many changes in protein expression and function, including alterations in the transcript DAPH levels of hundreds of genes, with different stimuli resulting in different patterns of transcriptional responses. As current nomenclature is inadequate to describe variable DC activation CIL-102 states, for the purposes of this report we will define a mature DC as an activated cell that displays enhanced antigen presentation capability. At a minimum, this requires increased surface display of MHCII-peptide complexes and costimulatory molecules, as well as expression of the chemokine receptor CCR7 that allows migrating DCs to reach tissue-draining lymph nodes and interact with T cells therein. For simplicity, we will therefore define a mature DC as one expressing high levels of these three molecules. As defined by our criteria, a relatively small percentage of BMDCs underwent spontaneous maturation without manipulation. We find that levels of spontaneous maturation range from 5�C20% in our hands. However, maturation was dramatically increased above spontaneous levels upon exposure to inflammatory stimulation. As previously reported, we also find that maturation is robustly induced by mechanical disruption of BMDC clusters. We confirmed by flow cytometry that both types of maturation stimuli activated the ����core���� aspects of the DC maturation response. BMDCs induced to mature by exposure to LPS are reported to orchestrate immunogenic T cell responses, while those matured by mechanical stimulation can coordinate tolerogenic responses. We confirmed this important distinction with a functional test similar to that first described with this model. We stimulated BMDC cultures either with LPS or with mechanical stimulation, pulsed the activated DCs with antigen, and used the DCs to immunize recipient mice. After 3 immunizations we harvested spleens from recipient mice and challenged splenocytes ex vivo with cognate antigen. We find that while both LPS- and mechanically-stimulated BMDCs prime the recall response equally well, the cytokine profile elicited by mechanicallystimulated BMDCs was distinct from that induced by LPS-stimulated BMDCs and consistent with immune tolerance.