Early events in dendritic cell maturation induced by LPS.

Immature dendritic cells (Dcs) are characterised by high antigen uptake ability and poor T-cell stimulatory function. In contrast, mature DCs have a high stimulatory function and poor antigen uptake ability. Inflammatory stimuli induce DC maturation and migration from nonlymphoid tissues to lymphoid organs. We investigated the effect of lipopolysaccharide (LPS) on DC antigen uptake and migratory function at early and late stimulation time points. We observed that the transition from the immature to the mature state is not a progressive itinerary, but it is characterised by precise functional stages. At early time points after LPS stimulation DCs significantly decrease their intrinsic migratory ability and increase the antigen uptake function. Later, around 4 h after LPS activation, DCs show recovery of migratory ability and start to progressively lose their antigen uptake function until the mature stage in which they show poor antigen uptake and migratory activity.