CD8α+ dendritic cells originate from the CD8α- dendritic cell subset by a maturation process involving CD8α, DEC-205, and CD24 up-regulation

CD8alpha(+) and CD8alpha(-) dendritic cells (DCs) have been considered as independent DC subpopulations both ontogenetically and functionally during recent years. However, it has been demonstrated that both DC subsets can be generated from a single precursor population, supporting the concept that they do not represent separate DC lineages. By using highly purified splenic CD8alpha(-) DCs, which were injected intravenously and traced by means of an Ly5.1/Ly5.2 transfer system, this study shows that CD8alpha(-) DCs acquired the phenotypic characteristics of CD8alpha(+) DCs, by a differentiation process involving CD8alpha, DEC-205, and CD24 up-regulation, paralleled by the down-regulation of CD11b, F4/80, and CD4. These data demonstrate that CD8alpha(+) DCs derive from CD8alpha(-) DCs, and strongly support that CD8alpha(-) and CD8alpha(+) DCs represent different maturation or differentiation stages of the same DC population. Therefore, CD8alpha(+) DCs would represent the last stage of DC differentiation, playing an essential role in the induction of T-cell responses, due to their antigen-presenting potential, cross-priming ability, and capacity to secrete large amounts of key cytokines such as interferon gamma and interleukin-12. (C) 2002 by The American Society of Hematology.