title: Interleukin-16 stimulates the expression and production of pro-inflammatory cytokines by human monocytes.
abstract: Interleukin-16 (IL-16) acts as a chemoattractant for CD4+ cells, as a modulator of T-cell activation, and plays a key role in asthma. This report describes the cytokine-inducing effects of IL-16 on total peripheral blood mononuclear cells (PBMC) and PBMC subpopulations. While CD4+ T lymphocytes did not secrete cytokines in response to rhIL-16, CD14+ CD4+ monocytes and maturing macrophages secrete IL-1beta, IL-6, IL-15 and tumour necrosis factor-alpha (TNF-alpha) upon rhIL-16 stimulation. The mRNA species for these four cytokines were detected as early as 4 hr post-stimulation, with protein being secreted by 24 hr. Secretion of IL-1beta and IL-6 by total PBMC was dose dependent, with maximal secretion being observed using 50 ng/ml rhIL-16. However, for IL-15 or TNF-alpha maximal secretion by total PBMC occurred with all concentrations between 5 ng/ml to 500 ng/ml rhIL-16. Purified monocytes/macrophages secreted maximal concentrations of all four cytokines in the presence of 500 ng/ml rhIL-16, except for monocytes where maximal secretion of IL-15 was, interestingly, observed with only 50 ng/ml rhIL-16. The use of higher concentrations of rhIL-16 (1000 ng/ml) inhibited secretion of all four cytokines. While these IL-16-induced cytokines are likely to be involved in the immune system's response to antigen, the data suggest that IL-16 may play a key role in initiating and/or sustaining an inflammatory response.
authors.affiliation: Paul-Ehrlich-Institute, Langen, Germany and Roche Diagnostics GmbH, Pharma Research, Penzberg, Germany.
authors.forename: N L
authors.initials: NL
authors.lastname: Mathy
authors.forename: W
authors.initials: W
authors.lastname: Scheuer
authors.forename: M
authors.initials: M
authors.lastname: Lanzendörfer
authors.forename: K
authors.initials: K
authors.lastname: Honold
authors.forename: D
authors.initials: D
authors.lastname: Ambrosius
authors.forename: S
authors.initials: S
authors.lastname: Norley
authors.forename: R
authors.initials: R
authors.lastname: Kurth
mesh_terms: D015704:CD4 Antigens / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019410:Interleukin-16 / Q000276:immunology*; D018950:Lipopolysaccharide Receptors / Q000032:analysis; D008264:Macrophages / Q000276:immunology; D009000:Monocytes / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D015704:CD4 Antigens; D016207:Cytokines; D019410:Interleukin-16; D018950:Lipopolysaccharide Receptors; D012333:RNA, Messenger