Dendritic Cell Development in Culture from Thymic Precursor Cells in the Absence of Granulocyte/Macrophage Colony-stimulating Factor

Abstract

The earliest lymphoid precursor population in the adult mouse thymus had previously been shown to produce not only T cells, but also dendritic cell (DC) progeny on transfer to irradiated recipients. In this study, culture of these isolated thymic precursors with a mixture of cytokines induced them to proliferate and to differentiate to DC, but not to T lineage cells. At least 70% of the individual precursors had the capacity to form DC. The resultant DC were as effective as normal thymic DC in the functional test of T cell stimulation in mixed leukocyte cultures. The cultured DC also expressed high levels of class I and class II major histocompatibility complex, together with CD11c, DEC-205, CD80, and CD86, markers characteristic of mature DC in general. However, they did not express CD8α or BP-1, markers characteristic of normal thymic DC. The optimized mixture of five to seven cytokines required for DC development from these thymic precursors did not include granulocyte/macrophage colony stimulating factor (GM-CSF), usually required for DC development in culture. The addition of anti–GM-CSF antibody or the use of precursors from GM-CSF–deficient mice did not prevent DC development. Addition of GM-CSF was without effect on DC yield when interleukin (IL) 3 and IL-7 were present, although some stimulation by GM-CSF was noted in their absence. In contrast, DC development was enhanced by addition of the Flt3/Flk2 ligand, in line with the effects of the administration of this cytokine in vivo. The results indicate that the development of a particular lineage of DC, probably those of lymphoid precursor origin, may be independent of the myeloid hormone GM-CSF.

CD4 and CD8 Expression by Dendritic Cell Subtypes in Mouse Thymus and Spleen

“…Although formal clonal proof of a common lymphoid/DC precursor is still missing, it is clear that these DC represent a distinct lineage with distinct cytokine requirements and transcription factor control (18,19). They also have a very much greater potential to produce IL-12 than either of the CD8 Ϫ DC populations (Ref.…”

“…The murine lymphoid-related DC lineage differs from myeloidrelated DC both in the cytokine requirements for development and in transcription factor control (18,19). However, the expression of CD8␣ by the lymphoid-related DC does not appear to be essential for either their development or their function (18,20), so it may be a relic of their particular developmental history. No CD8 expression has been detected on human DC (21).…”

“…CD8␣ ϩ thymic or splenic DC can be produced in recipient mice on transfer of an early thymic lymphoid precursor population with little, if any, capacity to form myeloid cells (16,17). The murine lymphoid-related DC lineage differs from myeloidrelated DC both in the cytokine requirements for development and in transcription factor control (18,19). However, the expression of CD8␣ by the lymphoid-related DC does not appear to be essential for either their development or their function (18,20), so it may be a relic of their particular developmental history.…”

CD134L Expression on Dendritic Cells in the Mesenteric Lymph Nodes Drives Colitis in T Cell-Restored SCID Mice

“…In all cases, the CD134L ϩ cells were CD11c positive, suggesting that these cells are DC. They were also found to be CD11b ϩ and CD8␣ Ϫ , suggesting that they are of myeloid origin (49).…”

Generation of Macrophages from Early T Progenitors In Vitro

“…As reviewed by Shortman et al in detail (16), the c-kit ϩ CD44 ϩ CD25 Ϫ (pro-T1) cells have previously been shown to have the capacity to form B cells, NK cells, and thymic DCs, as well as T cells, but not erythroid or myeloid cells, under the conditions tested at that time (15). The next downstream precursor, pro-T2 cells, appeared to have lost B cell and NK cell potential but still retained the capacity to form DCs.…”