title: Liu-He-Tang inhibited plaque formation by human respiratory syncytial virus infection in cell lines of the human respiratory tract.
abstract: BACKGROUND
  Liu-He-Tang (LHT) has been used to treat adult respiratory tract infection with productive cough and fever for a thousand years in ancient China. Adults with respiratory tract infection of human respiratory syncytial virus (HRSV) can have symptoms similar to those managed by LHT. Therefore, LHT is supposed to be beneficial for adult HRSV infection. However, LHT does not have any antiviral activity to support its use against HRSV infection.
  
  
  OBJECTIVE
  HRSV is the most important virus causing serious pediatric respiratory tract infections worldwide. HRSV also contributes considerably to respiratory tract illness in adults. There is no effective therapeutic modality against HRSV infection. In order to find readily available agents to manage adult HRSV infection, this study tested the hypothesis that LHT has antiviral activity against HRSV-induced cytopathy.
  
  
  METHODS
  Effect of the hot water extract of LHT on HRSV was tested by plaque reduction assay in both human upper (HEp-2) and low (A549) respiratory tract cell lines and also a human normal fibroblast cell line (WI-38). Ability of LHT to stimulate anti-viral cytokines was evaluated by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  LHT could dose-dependently inhibit HRSV-induced plaque formation (p < 0.0001), especially in A549 cell. 300 μg/ml LHT nearly abolished plaque formation in A549 cells. LHT was more effective when given before viral inoculation (p < 0.0001). LHT dose-dependently inhibited viral attachment (p < 0.0001). Besides, LHT could inhibit HRSV internalization both time-dependently and dose-dependently (p < 0.0001). Furthermore, LHT stimulated epithelial cells to secrete IFN-β and TNF-α to counteract HRSV infection before infection becomes established.
  
  
  CONCLUSIONS
  LHT has anti-HRSV activity that provides a basic support of its possible use in managing adult HRSV infection.
authors.affiliation: Department of Renal Care, College of Medicine, Kaohsiung Medical University, Ping-Tung 907, Taiwan.
authors.forename: Jung San
authors.initials: JS
authors.lastname: Chang
authors.forename: Kuo Chih
authors.initials: KC
authors.lastname: Wang
authors.forename: Den En
authors.initials: DE
authors.lastname: Shieh
authors.forename: Lien Chai
authors.initials: LC
authors.lastname: Chiang
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D003588:Cytopathogenic Effect, Viral / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D016899:Interferon-beta / Q000378:metabolism; D018357:Respiratory Syncytial Virus Infections / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000187:drug effects* / Q000254:growth & development; D012137:Respiratory System / Q000187:drug effects* / Q000276:immunology / Q000821:virology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D010948:Viral Plaque Assay; D053585:Virus Attachment / Q000187:drug effects; D053586:Virus Internalization / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D004365:Drugs, Chinese Herbal; D014409:Tumor Necrosis Factor-alpha; C569973:liu-he-tang; D016899:Interferon-beta