Dendritic cells capable of stimulating T cells in germinal centres.

The B cells within the germinal centres of lymphoid organs undergo affinity maturation of their antigen receptors, a critical event for antibody memory. Follicular dendritic cells within the germinal centres retain immune complexes that select the developing B cells for which they have a higher affinity. We have now identified a subset of CD4+ CD11c+ CD3- dendritic cells in the germinal centres. These are strong antigen-presenting cells for T cells, but do not co-stimulate CD40-activated B cells. These dendritic cells probably stimulate germinal centre T cells and aid the complicated processes that are required for the generation of memory B cells.