An in vitro evaluation of the potential suitability of peripheral blood CD14(+) and bone marrow CD34(+)-derived dendritic cells for a tolerance inducing regimen in the primate.

Dendritic cells (DC) represent a tool not only for immune activation, but also potentially for tolerance induction in transplantation. This latter approach is yet to be explored in a pre-clinical primate model. Since no information concerning baboon DC has been available, we characterised the DC of this species derived in vitro from bone marrow (CD34(+)) and peripheral blood (CD14(+)) precursors to determine which would be the most suitable for a tolerance inducing strategy. Baboon DC were differentiated in vitro using protocols similar to those used in humans and their maturation status was assessed and compared according to their phenotype and function. Based on both phenotypic and functional criteria, the CD14-derived baboon DC appeared to be less mature DC, necessitating an additional stimulus in order to become fully mature. The CD34-derived DC on the other hand appeared more mature in nature, without necessarily requiring exposure to overt maturation signals. We suggest therefore that, in the baboon, peripheral blood CD14-derived DC may be more suitable for protocols where tolerance induction is the goal. We now aim to perform further in vitro investigations into the potential tolerance inducing effects of CD14-derived DC alone or in association with other strategies that would be applicable in vivo.