title: Synergistic effect of high-mobility group box-1 and lipopolysaccharide on cytokine induction in bovine peripheral blood mononuclear cells.
abstract: High-mobility group box 1 (HMGB1) is one of the potent endogenous adjuvants released by necrotic and activated innate immune cells. HMGB1 modulates innate and adaptive immune responses in humans and mice by mediating immune cells crosstalk. However, the immuno-modulatory effects of HMGB1 in the bovine immune system are not clearly known. In this study, the effect of bovine HMGB1 alone or in combination with LPS on the expression kinetics of cytokines upon in vitro stimulation of bovine peripheral blood mononuclear cells (PBMCs) was investigated by quantitative PCR assay. The biological activity of bovine HMGB1 expressed in this prokaryotic expression system was confirmed by its ability to induce nitric oxide secretion in RAW 264.7 cells. The present results indicate that HMGB1 induces a more delayed TNF-α response than does LPS in stimulated PBMCs. However, IFN-γ, IFN-β and IL-12 mRNA transcription peaked at 6 hr post stimulation after both treatments. Further, HMGB1 and LPS heterocomplex up-regulated TNF-α, IFN-γ and IL-12 mRNA expression significantly than did individual TLR4 agonists. The heterocomplex also enhanced the expression of TLR4 on bovine PBMCs. In conclusion, the data indicate that HMGB1 and LPS act synergistically and enhance proinflammatory cytokines, thereby eliciting Th1 responses in bovine PBMCs. These results suggest that HMGB1 can act as an adjuvant in modulating the bovine immune system and thus lays a foundation for using HMGB1 as an adjuvant in various bovine vaccine preparations.
authors.affiliation: Foot and Mouth Disease Research Center, Indian Veterinary Research Institute, Bangalore 560024, India.
authors.forename: Elamurugan
authors.initials: E
authors.lastname: Appavoo
authors.affiliation: Foot and Mouth Disease Research Center, Indian Veterinary Research Institute, Bangalore 560024, India.
authors.forename: Irshad Ahmed
authors.initials: IA
authors.lastname: Hajam
authors.affiliation: Foot and Mouth Disease Research Center, Indian Veterinary Research Institute, Bangalore 560024, India.
authors.forename: Narayanan Selvaraj
authors.initials: NS
authors.lastname: Muneeswaran
authors.affiliation: Foot and Mouth Disease Research Center, Indian Veterinary Research Institute, Bangalore 560024, India.
authors.forename: Ganesh
authors.initials: G
authors.lastname: Kondabattula
authors.affiliation: Foot and Mouth Disease Research Center, Indian Veterinary Research Institute, Bangalore 560024, India.
authors.forename: Veerakyathappa
authors.initials: V
authors.lastname: Bhanuprakash
authors.affiliation: Foot and Mouth Disease Research Center, Indian Veterinary Research Institute, Bangalore 560024, India.
authors.forename: Subodh
authors.initials: S
authors.lastname: Kishore
mesh_terms: D000818:Animals; D002417:Cattle; D016207:Cytokines / Q000096:biosynthesis* / Q000097:blood; D004357:Drug Synergism; D024243:HMGB1 Protein / Q000276:immunology / Q000494:pharmacology*; D007113:Immunity, Innate / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology*; D051379:Mice; D009336:Necrosis; D009569:Nitric Oxide / Q000378:metabolism; D000067996:RAW 264.7 Cells; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051197:Toll-Like Receptor 4 / Q000096:biosynthesis; D015854:Up-Regulation
chemical_list: D016207:Cytokines; D024243:HMGB1 Protein; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D011994:Recombinant Proteins; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D009569:Nitric Oxide
keywords: bovine; high-mobility group box 1; proinflammatory cytokines; synergism