Neonatal dendritic cells.

The capacity of lymphoid dendritic cells from human cord blood or adult peripheral blood to support a mixed leukocyte reaction in cord blood and adult T cells has been compared. Cord blood dendritic cells have a limited ability to induce either adult or cord blood T cells to proliferate in response to typical concentration of phytohemagglutinin or concanavalin A. Adult blood dendritic cells, on the other hand, induce equivalent mitogen responses in cord blood and adult blood T cells. This relative deficiency can be overcome by increasing the concentration of mitogen or the numbers of dendritic cells in the culture. Neonatal primary immune responses may, in part, reflect the reduced function of dendritic cells.