title: Differential regulation of cytokine and chemokine production in lipopolysaccharide-induced tolerance and priming.
abstract: LPS pretreatment of human pro-monocytic THP-1 cells induces tolerance to secondary LPS stimulation with reduced TNFalpha production. However, secondary stimulation with heat-killed Staphylococcus aureus (HKSa) induces priming as evidenced by augmented TNFalpha production. The pro-inflammatory cytokine, IFNgamma, also abolishes suppression of TNFalpha in LPS tolerance. The effect of LPS tolerance on HKSa and IFNgamma-induced inflammatory mediator production is not well defined. We hypothesized that LPS, HKSa and IFNgamma differentially regulate pro-inflammatory mediators and chemokine production in LPS-induced tolerance. THP-1 cells were pretreated for 24 h with LPS (100 ng/ml) or LPS (100 ng/ml) + IFNgamma (1 microg/ml). Cells were subsequently stimulated with LPS or HKSa (10 microg/ml) for 24 h. The production of the cytokines TNFalpha, IL-6, IL-1beta, and GMCSF and the chemokine IL-8 were measured in supernatants. LPS and HKSa stimulated TNFalpha (3070 +/- 711 pg/ml and 217 +/- 9 pg/ml, respectively) and IL-6 (237 +/- 8.9 pg/ml and 56.2 +/- 2.9 pg/ml, p < 0.05, n = 3, respectively) in control cells compared to basal levels (< 25 pg/ml). LPS induced tolerance to secondary LPS stimulation as evidenced by a 90% (p < 0.05, n = 3) reduction in TNFalpha. However, LPS pretreatment induced priming to HKSa as demonstrated by increased TNFalpha (2.7 fold, from 217 to 580 pg/ml, p < 0.05, n = 3 ). In contrast to suppressed TNFalpha, IL-6 production was augmented to secondary LPS stimulation (9 fold, from 237 to 2076 pg/ml, p < 0.01, n = 3) and also primed to HKSa stimulation (62 fold, from 56 to 3470 pg/ml, p < 0.01, n = 3). LPS induced IL-8 production and to a lesser extent IL-1beta and GMCSF. LPS pretreatment did not affect secondary LPS stimulated IL-8 or IL-1beta, although HKSa stimulation augmented both mediators. In addition, IFNgamma pretreatment reversed LPS tolerance as evidenced by increased TNFalpha levels while IL-6, IL-1beta, and GMCSF levels were further augmented. However, IL-8 production was not affected by IFNgamma. These data support our hypothesis of differential regulation of cytokines and chemokines in gram-negative- and gram-positive-induced inflammatory events. Such changes may have implications in the pathogenesis of polymicrobial sepsis.
authors.affiliation: Department of Physiology and Neuroscience, The Medical University of South Carolina, Charleston 29425, SC, USA.
authors.forename: Octavia M
authors.initials: OM
authors.lastname: Peck
authors.forename: David L
authors.initials: DL
authors.lastname: Williams
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Breuel
authors.forename: John H
authors.initials: JH
authors.lastname: Kalbfleisch
authors.forename: Hongkuan
authors.initials: H
authors.lastname: Fan
authors.forename: George E
authors.initials: GE
authors.lastname: Tempel
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Teti
authors.forename: James A
authors.initials: JA
authors.lastname: Cook
mesh_terms: D018925:Chemokines / Q000276:immunology / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology / Q000502:physiology*; D007375:Interleukin-1 / Q000276:immunology / Q000378:metabolism; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism; D016209:Interleukin-8 / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism*
chemical_list: D018925:Chemokines; D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor