title: Suppressive Effects of Chronic Stress on Influenza Virus Protection after Vaccination with Plasmid DNA-Encoded Nucleoprotein.
abstract: BACKGROUND
  Influenza is a highly infectious and acute respiratory disease caused by an infection of the host respiratory tract mucosa by the influenza virus. The use of DNA vaccines that express conserved genes such as nucleoprotein (NP) represents a new method of vaccination against influenza. In this study, the effect of chronic stress on the efficiency of this type of vaccine has been evaluated in a mouse model.
  
  
  METHODS
  The NP DNA vaccine was administered intradermally 3 times on days 0, 3 and 6 to stressed and nonstressed male BALB/c mice. Two weeks after the last immunization, half of these mice were challenged with A/Puerto Rico/8/34 (PR8) influenza virus and were weighed for 12 days, and their mortality rate was assessed during this period. The cellular immune response of the other half of the mice was evaluated by cytotoxicity assay.
  
  
  RESULTS
  The results indicate a significant reduction in the cytotoxic T-lymphocyte response of stressed mice in comparison with unstressed mice. Also, the percentage of weight loss and mortality after the challenge in stressed mice was significantly increased compared to the other group.
  
  
  CONCLUSIONS
  These results indicate that the NP DNA vaccine is not able to induce any effective cytotoxic T-lymphocyte response against influenza virus in stressed mice and cannot induce protective immunity against influenza infection in this group of mice.
authors.affiliation: Department of Microbiology, Faculty of Biological Sciences, Shahid-Beheshti University, Tehran, Iran.
authors.forename: Fatemeh Sadat
authors.initials: FS
authors.lastname: Nezam
authors.forename: Seyed Masoud
authors.initials: SM
authors.lastname: Hosseini
authors.forename: Masoumeh Tavassoti
authors.initials: MT
authors.lastname: Kheiri
authors.forename: Asghar
authors.initials: A
authors.lastname: Abdoli
authors.forename: Arash
authors.initials: A
authors.lastname: Memarnejadian
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shenagari
authors.forename: Shima
authors.initials: S
authors.lastname: Gholami
authors.forename: Hesam
authors.initials: H
authors.lastname: Sohani
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Rahmatollahi
authors.forename: Abbas
authors.initials: A
authors.lastname: Jamali
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D007252:Influenza Vaccines / Q000235:genetics / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009698:Nucleoproteins / Q000276:immunology*; D013315:Stress, Psychological / Q000276:immunology / Q000628:therapy*; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors; D019444:Vaccines, DNA / Q000627:therapeutic use*
chemical_list: D007252:Influenza Vaccines; D009698:Nucleoproteins; D019444:Vaccines, DNA