As an initial step to understanding tolerogenic function in BMDCs, we sought to better understand the molecular mechanisms by which mechanical Clofilium tosylate stimulation induces maturation. Previous studies with mechanical stimulation have utilized relatively poorly defined stimuli to introduce mechanical stimulation, such as simple pipetting or purification with magnetic beads, which has hampered the ability to precisely identify the molecular mechanisms that mediate the ensuing response. It has been proposed that mechanical disruption of homotypic ECadherin interactions between adjacent BMDCs initiates bcatenin signaling and the tolerogenic response. We found, however, that individual BMDCs can respond to mechanical signals independently of the disruption of cell-cell interactions. Therefore, BMDCs appear intrinsically capable of responding to mechanical signals. This finding implicates the involvement of alternative molecules in addition to E-Cadherin in the response to mechanical stimulation. In addition to cadherins, integrins also make important contributions to cellular responses to mechanical signals. DCs express high levels of b2 integrins, including CD11b and the DC lineage-associated CD11c. We reasoned that if integrins are involved in initiating signaling events in response to mechanical stimulation, it might be possible to mimic mechanical stimulation with a defined stimulus against BMDC integrins. This approach also has the desirable advantage of circumventing the poorly defined stimulus of repeated pipetting to introduce mechanical signals. To determine whether direct stimulation of integrins initiates maturation similar to that induced by mechanical agitation, we stimulated BMDC cultures with an antibody to CD11b.We found that integrins can indeed initiate maturation, albeit to slightly lower levels than that observed with mechanical stimulation. This response to CD11b MAb was dependent on the presence of CD11b, as evidenced by the absence of a similar response from CD11b-/- BMDCs. However, the BMDC response to mechanical stimulation did not require the Dihydroeponemycin participation of CD11b under our standard conditions, as it occurred normally in cells from CD11b-/- mice. We conclude that although integrins such as CD11b can facilitate DC maturation consistent with mechanical agitation, the tolerogenic response to mechanical stimulation is not uniquely dependent on a single integrin.