Differential Induction of IL-1β and TNF by CD40 Ligand or Cellular Contact with Stimulated T Cells Depends on the Maturation Stage of Human Monocytes

Abstract

Cellular contact with stimulated T cells potently induces cytokine production in monocytes, a mechanism that is likely to be relevant to chronic inflammation. Although the identity of surface molecules involved in this process remains elusive, CD40 and its ligand, CD40L, are thought to be implicated, considering that they are expressed at the inflammatory site. To ascertain the involvement of CD40L, we compared the activation of three different types of human monocytic cells, i.e., freshly isolated monocytes, monocytes primed with IFN-γ (IFN-γ-macrophages), and THP-1 cells. These cells were activated by either membranes isolated from stimulated T cells (HUT-78 or T lymphocytes) to mimic cellular contact, soluble extracts from isolated membranes, or CD40L trimer (CD40LT). The production of TNF and IL-1β was induced by membranes of stimulated T cells in the three types of target cells, whereas CD40LT induced TNF production in IFN-γ-macrophages only. Similar results were obtained with soluble extracts of T cell membranes, demonstrating that the difference between membranes and CD40LT was not due to the particulate form of membranes. CD40LT induced neither transcript nor protein of cytokines in monocytes, whereas in IFN-γ-macrophages, IL-1β and TNF mRNA were observed, but only TNF was measured in cell supernatants. Finally, anti-CD40L Abs failed to inhibit TNF and IL-1β production induced in IFN-γ-macrophages by solubilized membranes, whereas TNF production induced by CD40LT was inhibited. These results demonstrate that CD40L is not required in monocyte activation by direct cellular contact with stimulated T cells, although soluble CD40LT induces the production of TNF in IFN-γ-macrophages.

Glatiramer acetate increases IL-1 receptor antagonist but decreases T cell-induced IL-1β in human monocytes and multiple sclerosis

“…Previous studies demonstrated that fixed, stimulated HUT-78 cells, plasma membranes of the latter cells, and CEsHUT display similar ability to induce cytokine production in human monocytes (15). To activate monocytes, CE sHUT was used at either 1 g/mL or 6 g/mL proteins as previously determined (38,44).…”

“…HUT-78 cells (2 ϫ 10 6 cells/mL) were stimulated for 6 h by phytohemagglutinin (1 g/mL) and PMA (5 ng/mL). Plasma membranes of stimulated HUT-78 cells were prepared as previously described and solubilized in 8 mM CHAPS (23,44). CHAPS extract of membranes of stimulated HUT-78 cells was referred as to CE sHUT.…”

Monocytes are activated in patients with myelodysplastic syndromes and can contribute to bone marrow failure through CD40–CD40L interactions with T helper cells

“…17 Increased surface expression of the CD40 receptor on MDS monocytes could account for this different behavior, but also activation of different downstream pathways might be responsible. 30 This remains to be explored. In addition, we analyzed the effects of inhibiting this pathway in colony formation assays, using the monoclonal antibody ch5D12, which is an antagonist chimeric anti-human CD40 antibody that has been shown to be effective in the therapy of inflammatory bowel disease 22 and non-human primate models of autoimmune encephalomyelitis.…”

“…The CD40 receptor is a 45-50 kDa type I phosphoprotein that is a member of the TNF receptor superfamily. It has been demonstrated that monocytes express low levels of CD40, 30 but expression of the CD40 gene is induced upon activation, which is most pronounced by stimulation with IFN-g. 27 Besides production of TNF-a, CD40 ligation also results in the secretion of other pro-inflammatory cytokines and chemokines such as IL-1, IL-6, IL-8, IL-10, IL-12 and macrophage-inflammatory protein-1a. 18,19 In addition, ligation of CD40 by CD40L, present on T helper cells, promotes upregulation of co-stimulatory molecules (CD40, CD80, CD86, MHC class II molecules) and FasL.…”

Interleukin-1β production in human monocytes/macrophages is differentially regulated by MEK1 upon sterile and infectious inflammatory conditions

“…HUT-78 cells were cultured and activated by PHA (1 µg/ml) and PMA (5 ng/ml) in RPMI 1640 medium supplemented with 10% heat activated FCS, 50 µg/ml streptomycin, 50 U/ml penicillin, 2 mM glutamine (complete RPMI medium) in a 5% CO 2 -air humidified atmosphere at 37°C as described elsewhere [34]. Plasma membranes of stimulated HUT-78 cells were isolated and solubilized with CHAPS to obtain membrane CHAPS extract (CE sHUT ) as previously described [35].…”