Mouse and human dendritic cell subtypes

Key Points The dendritic cell (DC) systems of human and mouse are similar. Many apparent distinctions between human and murine DCs reflect differences in tissue origin and differences between cultured and freshly isolated DCs. Human and mouse DCs can be divided into several subtypes on the basis of surface antigen differences. Many DC subtypes respond differently to microbial products, produce different cytokines and regulate the responses of the T cells they activate. DC subtypes differ in their functional potential but the expression of function is flexible and regulated by environmental factors. Many DC subtypes are products of separate developmental sublineages with different immediate precursors (pDC). DC can be of myeloid or lymphoid origin but this does not determine the DC subtype produced. Some DC sublineages only produce DCs from pDCs in response to microbial products or other danger signals. Some DC subtypes remain in a mature but quiescent state unless activated by microbial products or other danger signals. The dynamics of these shifts in the DC system in response to microbial invasion might determine the balance between tolerance and immunity.