A method is provided, including obtaining a population of antigen-presenting cells, enriching a population of stem/progenitor cells within a larger population of cells, activating the population of antigen-presenting cells and, following the activating, inducing at least one process selected from the group consisting of: differentiation, expansion, activation, secretion of a molecule, and expression of a marker, by exposing the enriched stem/progenitor cell population to the population of antigen-presenting cells. Other applications are also described.