title: Inhibitory Effect of TNF-alpha Produced by Macrophages Stimulated with Grifola frondosa Extract (ME) on the Growth of Influenza A/Aichi/2/68 Virus in MDCK Cells.
abstract: We investigated the inhibitory effect of the conditioned medium (CM) from P338D1 (D1) cells, a murine macrophage cell line, stimulated for 10 hours with a fixed dose (100 mug/ml) of the extracts from the fruit bodies of Grifola frondosa (ME) or its ultra filtration-based fractions (MFs), on the growth of influenza A/Aichi/2/68 virus in Madin-Darby canine kidney cells. Direct addition of ME and 3 kinds of MFs (MF1, MF2 and MF3) to the infected cells had no obvious inhibitory effect. However, virus yields were reduced in the presence of CMs. Notably, the inhibitory effect of the CM prepared by using MF2 (molecular weight of 30 Kd to 100 Kd) was the strongest (28% reduction compared to the control). RT-PCR and ELISA assays showed that the CMs could induce the expression of TNF-alpha mRNA in D1 cells leading to production of TNF-alpha, known as an antiviral cytokine. These findings suggest that ME and MFs (especially MF-2) might induce the production of certain factors, including TNF-alpha, which are responsible for the inhibition of viral growth in vitro.
authors.affiliation: Departments of Oriental Medicine, Sugitani 2630, Toyama 930-0194, Japan. inobuko@med.u-toyama.ac.jp
authors.forename: Nobuko
authors.initials: N
authors.lastname: Obi
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hayashi
authors.forename: Tatsurou
authors.initials: T
authors.lastname: Miyahara
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Shimada
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Terasawa
authors.forename: Masataka
authors.initials: M
authors.lastname: Watanabe
authors.forename: Masahide
authors.initials: M
authors.lastname: Takeyama
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Obi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ochiai
mesh_terms: D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D017077:Culture Media, Conditioned / Q000737:chemistry / Q000494:pharmacology; D004285:Dogs; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000494:pharmacology*; D048691:Grifola / Q000737:chemistry*; D009980:Influenza A virus / Q000187:drug effects / Q000254:growth & development*; D008264:Macrophages / Q000737:chemistry / Q000187:drug effects / Q000276:immunology*; D051379:Mice; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology*
chemical_list: D017077:Culture Media, Conditioned; D004365:Drugs, Chinese Herbal; D014409:Tumor Necrosis Factor-alpha