title: Evaluation of Immune Response Against Inactivated Avian Influenza (H9N2) Vaccine, by Using Chitosan Nanoparticles.
abstract: BACKGROUND
  Influenza A is a virus that affects a wide range of animals and also human beings. Avian influenza virus (AIV) subtype H9N2 has the potential to create influenza pandemic and vaccination is a common solution for this problem. The vaccine, used for rapid intervention, should be safe to use and highly effective, after a single administration. Chitosan nanoparticles (CNP) have already been recommended as a new adjuvant for inactivated AIV H9N2 vaccine immunization.
  
  
  OBJECTIVE
  This study aimed at the evaluation and better understanding of optimum concentration of CNP preparations and also, assessment of loading capacity of AIV into CNP, as an adjuvant in specific pathogen-free (SPF) chickens.
  
  
  METHODS
  For measurement of vaccine-antibody response, different types of CNP were injected intramuscularly, in a single dose, to 21-day-old specific pathogen-free chickens. Chickens were monitored for the efficacy of the nanoparticles and, also, their immune response, during a follow up of 7 weeks, by using hemagglutination-inhibition (HI) test. The CNP were prepared according to modified ionic gelation method and inactivated antigen was loaded in four hemagglutinin units (HAU) concentrations. Loading capacity of nanoparticles was determined by hemagglutination (HA) method. Inactivated A/H9N2 AIV was mixed with chitosan of low molecular weight.
  
  
  RESULTS
  The CNP did not cause any mortality or side effects, when chickens were administered the prepared vaccine. The results strongly showed that this novel vaccine significantly enhances the immunogenicity of inactivated AIV, comparing with ISA70 (SEPPIC, Puteaux, France) adjuvant that is used routinely in the Razi Serum and Vaccine Research and Production Institute, Karaj, Iran, to reduce ISA70's side effects.
  
  
  CONCLUSIONS
  The AIV loaded into CNP vaccines induce appropriate antibody titers, after a single immunization, while requiring a low dose of antigen. The CNP also represent an interesting new platform for antigen delivery and a promising adjuvant candidate for H9N2 inactivated influenza vaccine.
authors: Laboratory of Virus Biobank, Razi Vaccine and Serum Research Institute, Karaj, IR Iran.
authors: Iraj
authors: I
authors: Khalili
authors: Department of Research and Development, Razi Vaccine and Serum Research Institute, Ahvaz, IR Iran.
authors: Rahim
authors: R
authors: Ghadimipour
authors: Neurosciences Research Center, Tabriz University of Medical Science, Tabriz, IR Iran.
authors: Saeed
authors: S
authors: Sadigh Eteghad
authors: Department of Biotechnology, Razi Vaccine and Serum Research Institute, Mashhad, IR Iran.
authors: Mohsen
authors: M
authors: Fathi Najafi
authors: Department of Poultry Research and Vaccine Production, Razi Vaccine and Serum Research Institute, Karaj, IR Iran.
authors: Mohammad Majid
authors: MM
authors: Ebrahimi
authors: Department of Poultry Vaccines Quality Control, Razi Vaccine and Serum Research Institute, Karaj, IR Iran.
authors: Naser
authors: N
authors: Godsian
authors: Higher Education Institute of Rab-Rashidi, Tabriz, IR Iran.
authors: Yousef
authors: Y
authors: Sefidi Heris
authors: Department of Poultry Inactivated Vaccines, Razi Vaccine and Serum Research Institute, Marand, IR Iran.
authors: Mohammad Taghi
authors: MT
authors: Khalili
keywords: Chitosan; H9N2 Subtype; Hemagglutination Inhibition Tests; Influenza A Virus; Nanoparticles; Vaccines