Dendritic cells associated with plasmablast survival

A subset of myeloid dendritic cells is described which is associated with t he ability of splenic and lymph node plasmablasts to survive and differenti ate into plasma cells. Plasmablast-associated dendritic cells (PDC) are CD1 1c(high), DEC-205(-) and unlike conventional dendritic cells do not associa te with T cells. The following findings suggest a requirement for PDC if pl asmablasts are to differentiate to plasma cells. First, when large numbers of B cells are recruited into antibody responses and plasmablasts outgrow t he PDC stroma, only those associated with PDC survive and differentiate int o plasma cells. Conversely, if the number of PDC is increased by ligating t heir CD40, more plasmablasts survive on the expanded PDC stroma and differe ntiate into plasma cells. Finally, in T cell-deficient mice, the plasma cel ls that develop atypically in the T zones in response to thymus-independent antigens are associated with ectopic PDC.