TNF in combination with GM-CSF enhances the differentiation of neonatal cord blood stem cells into dendritic cells and macrophages

Abstract

We describe dendritic cell progenitors within the CD34+ stem cell compartment in neonatal cord blood and identify growth factors contributing to their differentiation. Granulocyte-macrophage colony-stimulating factor (GM-CSF), although mainly promoting the growth and differentiation of monocyte-macrophages (mono-m psi s), also induced the differentiation of cells with the distinctive morphological features of dendritic cells (DCs). Tumor necrosis factor (TNF) in combination with GM-CSF promoted further growth of both cell types but most notably increased the DC content. In situ analysis revealed that the cells exhibiting DC morphology were positive for class II major histocompatibility complex antigens but were CD14 negative, did not exhibit nonspecific esterase activity, and were nonphagocytic. Moreover, the mixed leukocyte reaction stimulatory capacity of cultures with the higher DC content was greater. TNF, interleukin-1 (IL-1), IL-6, or platelet-derived growth factor (PDGF) was inactive in promoting stem cell proliferation or DC morphology. IL-1 or PDGF synergized with GM-CSF to increase mono-m psi-associated cell proliferation but did not increase the DC content. The development of a common DC-monocyte precursor was suggested by the presence of colony-forming unit-like clusters containing mono-m psi s and DCs and one sharp proliferative peak. The loss of DC morphology after 21 days, coupled with increases in mono-m psi-associated markers and a constant number of viable cells, further suggests that DC morphology may fluctuate in culture or is a transient feature acquired by certain cells of the mono-m psi lineage.

The Cutaneous Response in Humans toTreponema pallidumLipoprotein Analogues Involves Cellular Elements of Both Innate and Adaptive Immunity

“…3) and are likely to represent locally recruited, resident Langerhans cells (43,70). Inasmuch as monocytes can differentiate into DC1 cells upon extended incubation with monocyte-conditioned medium (71) or various combinations of cytokines (e.g., IL-4, GM-CSF, TNF-␣) (49,(72)(73)(74)(75)(76), one could argue alternatively that the DC1 subset actually arose from infiltrating monocytes that differentiated in situ. Two lines of evidence indicate that this is unlikely to be the case.…”

“…Two lines of evidence indicate that this is unlikely to be the case. One is that the inflammatory milieu within the sites of injection induced monocytes to mature into activated macrophages rather than DCs, as evidenced by their increased expression of CD14, a surface marker lost when monocyte progenitors become DCs (72)(73)(74)(75)(76). Second, in accord with our in vivo findings, Randolph and coworkers (77) showed using an elegant in vitro model that monocytes differentiate into macrophages when they traverse endothelial monolayers, while only those cells that subsequently egress in the basal-toapical direction differentiate into DCs.…”

Viral Interleukin-10 Expressed by Human Cytomegalovirus during the Latent Phase of Infection Modulates Latently Infected Myeloid Cell Differentiation

“…Significant differences between values for the samples were determined by a one-tailed, paired Student's t test and are denoted by horizontal lines and asterisks as follows: ‫,ء‬ P value of Ͻ0.05; ‫,ءء‬ P value of Ͻ0.01. (20,31,38,39,45,60). TNF-␣, IL-6, IL-1␤, and TGF␤1 have all been linked to initiation of DC differentiation.…”

Human PBMC-derived dendritic cells transduced with an adenovirus vector induce cytotoxic T-lymphocyte responses against a vector-encoded antigen in vitro

“…Among professional APC, which include macrophages, B-lymphocytes and dendritic cells (DC), DC are the most potent stimulators of antigen-specific T-lymphocyte responses. 7,8 This potency, combined with the recent development of in vitro methods for the derivation of large numbers of DC from CD34 + haematopoietic progenitor cells [9][10][11] or peripheral blood mononuclear cells (PBMC) 12,13 make DC a prime target for therapeutic manipulation. As a consequence, induction of antitumour immune responses by DC after ex vivo antigen loading is currently subject to vigorous investigation.…”