Phagocytosis of co-developing neutrophil progenitors by dendritic cells in a culture of human CD34+ cells with granulocyte colony-stimulating factor and tumor necrosis factor-α

Abstract

Tumor necrosis factor-alpha (TNF-alpha) has been shown to induce the differentiation of CD34(+) cells toward dendritic cells (DCs). We have previously shown that DCs are co-generated from human CD34(+) cells during erythroid or megakaryocytic differentiation in the presence of TNF-alpha, and those DCs are able to stimulate autologous T cell proliferation. The aim of this study was to learn whether the co-stimulation of granulocyte colony-stimulating factor (G-CSF) and TNF-alpha would generate neutrophil progenitors and DCs together from human CD34(+) cells, and if this was the case, to clarify the phenotypic and functional characteristics of these DCs. When highly purified human CD34(+) cells were cultured for 7 days with G-CSF alone, the generated cells predominantly expressed a granulocyte marker, CD15, and then differentiated into neutrophils after 14 days of culture. The addition of TNF-alpha with G-CSF markedly decreased the number of CD15(+) cells without affecting the total number of cells during 7 days of culture. Almost one third of the generated cells were positive for CD11c and CD123. Furthermore, CD11c(+) cells were found to phagocytose CD15(+) cells and were able to induce allogeneic, but not autologous, T cell proliferation in the mixed lymphocyte reaction (MLR). On the other hand, the CD11c(+) cells generated by TNF-alpha and cytokines capable of inducing erythroid differentiation were able to stimulate autologous T cells. There was a difference in the expression of CD80, CD83 and CD86 among CD11c(+) cells induced by G-CSF plus TNF-alpha and those generated by interleukin-3, stem cell factor, and erythropoietin plus TNF-alpha. These results indicate that the co-stimulation of human CD34(+) cells with G-CSF and TNF-alpha induces the phagocytosis of co-developing neutrophil progenitors by DCs, and the stimulatory effects of these DCs on autologous T cells is different from that of DCs generated from CD34(+) cells during erythroid differentiation.

Delayed addition of tumor necrosis factor (TNF) antagonists inhibits the generation of CD11c+ dendritic cells derived from CD34+ cells exposed to TNF-α

“…We have reported previously that TNF-a promoted the formation of aggregates consisting of proliferating DCs [13,14,16]. The addition of etanercept at day 5 partially inhibited aggregate formation at days 7 and 10 ( Fig.…”

“…It is well established that TNF-a enhances proliferation and differentiation of DCs derived from human CD34 ? cells in the presence of SCF, granulocytemacrophage-CSF and IL-3 [5,6], and that TNF-a strongly inhibits the generation of erythroid, megakaryocytic, and granulocytic progenitor cells [13,14,16]. In our in vitro system, there is no continuous supply of CD34 ?…”

“…cells during the processes of erythroid [14,15], megakaryocytic [13] and granulocytic [16] differentiation. The CD11c ?…”

“…The CD11c ? DCs were found to be physically associated with and phagocytose developing and dying self-hematopoietic progenitor cells [13,14,16]. Using this system, we titrated the dose of the TNF antagonists etanercept, a soluble receptor construct, and infliximab, a chimeric monoclonal antibody, required to abolish the biologic effects of TNF-a and then examined the effects of delayed addition of TNF antagonists to this system.…”

CpG-ODN 2006 and human parvovirus B19 genome consensus sequences selectively inhibit growth and development of erythroid progenitor cells

“…23,25 For the simultaneous generation of erythroid, neutrophilic, and megakaryocytic progenitor cells, CD34 ϩ cells were suspended at a density of 2 ϫ 10 4 to 3 ϫ 10 4 cells/mL in the presence of 50 ng/mL IL-3, 50 ng/mL SCF, 2 IU/mL EPO, 100 ng/mL G-CSF, and 100 ng/mL TPO. Plasmacytoid dendritic cells (pDCs, CD11c Ϫ CD123 ϩ ), conventional DCs (cDCs, CD11c ϩ CD123 Ϫ ), and B cells (CD20 ϩ ) were isolated from normal human peripheral blood using MoFlo (Dako North America).…”