A linkage between dendritic cell and T-cell development in the mouse thymus: the capacity of sequential T-cell precursors to form dendritic cells in culture.

The earliest T precursor population in the adult mouse thymus (CD4lo8-3-44+25-c-kit+) was previously shown to be lymphoid-restricted (T, B, NK) but to have a capacity to form dendritic cells (DC). This led to the concept of a lineage of lymphoid-derived DC. DC could be generated with high efficiency in culture from this low CD4 precursor, using a complex mix of cytokines, a mix that notably did not include GM-CSF, the cytokine normally used for development in culture of myeloid-derived DC. Using this new culture system we now show that the capacity to form DC extends to the pro-T precursor population (CD4-8-3-44+25+c-kit+) but is lost by the pre-T precursor stage (CD4-8-3-44-25+c-kit+), the point of T-cell antigen-receptor beta-gene rearrangement. The DC generated in the cultures resemble mature thymic DC by most markers, but differ in their lack of expression of BP-1 and CD8 alpha.