title: IL-4 and IL-10 modulation of CD40-mediated signaling of monocyte IL-1beta synthesis and rescue from apoptosis.
abstract: Previous studies have demonstrated that the interaction of CD40 on monocytes with CD40 ligand, present on activated CD4+ T cells, induces monocyte inflammatory cytokine synthesis and rescues monocytes from apoptosis. These findings suggest a role for CD40 signaling of monocyte activation in the maintenance and/or exacerbation of nonseptic (e.g., autoimmune) inflammatory responses. In the present study the effects of the modulatory cytokines IL-4 and IL-10 on CD40-mediated signaling of monocyte IL-1beta synthesis and rescue from apoptosis were examined. Both IL-4 and IL-10 decreased CD40-dependent IL-1beta synthesis in a dose-dependent manner individually and synergized in this effect when used concurrently, with minimal effect on CD40 surface expression. CD40 signaling of IL-1beta synthesis was shown to be dependent on the induction of protein tyrosine kinase (PTK) activity, and both IL-4 and IL-10 diminished CD40-mediated tyrosine phosphorylation of monocyte cellular proteins. However, IL-4, but not IL-10, blocked CD40-mediated rescue from apoptosis, an event that we have demonstrated previously to be dependent on PTK activity as well. Together these results suggest that in monocytes 1) both IL-4 and IL-10 target CD40-induced PTK activity in the down-regulation of IL-1beta synthesis; and 2) IL-4 and IL-10 have divergent effects on the CD40 signaling pathway, in that these cytokines are synergistic with respect to their abilities to inhibit CD40-mediated IL-1beta synthesis and differ in their abilities to block CD40-mediated rescue from apoptosis.
authors.affiliation: Department of Biochemistry, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Poe
authors.forename: D H
authors.initials: DH
authors.lastname: Wagner
authors.forename: R W
authors.initials: RW
authors.lastname: Miller
authors.forename: R D
authors.initials: RD
authors.lastname: Stout
authors.forename: J
authors.initials: J
authors.lastname: Suttles
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D019013:CD40 Antigens / Q000378:metabolism*; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D016753:Interleukin-10 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000494:pharmacology*; D009000:Monocytes / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D019013:CD40 Antigens; D016753:Interleukin-10; D015847:Interleukin-4