title: Immunogenic potential and protective efficacy of formalin inactivated circulating Indian strain of West Nile virus.
abstract: OBJECTIVE
  To assess the best suitable condition for virus inactivation, and to study the immunogenic potential and protective efficacy of a circulating West Nile virus (WNV) strain in Assam.
  
  
  METHODS
  Bulk preparation of circulating WNV: WNIRGC07 (GeneBank ID: HQ246154), was undertaken in a bioreactor using cytodex-1. Virus Inactivation was done in three different conditions; 22 °C, 4 °C and room temperature. The virus preparations were evaluated for antigenicity by ELISA and toxicity by cell proliferation kit. Virus efficacy was done in-vivo on swiss albino mice against standard Indian WNV and Japanese encephalitis virus (JEV) strain. Humoral and cell mediated immune response was evaluated in mice sera by ELISA and neutralization assay.
  
  
  RESULTS
  Inactivation at 22 °C was found to be more suitable in terms of less toxicity and high antigenicity. The same was selected to study the immune response and efficacy in mice. It induced neutralizing antibody titre of 1: 625 and high IgG response. In vivo experiment showed 100% protective efficacy against WNV and 20.8% cross protective efficacy against JEV. Further assessment of cellular immunity through immunized mice revealed augmentation of high levels of pro-inflammatory cytokines and moderate levels of anti-cytokines indicating a mixed balance of Th1 and Th2 response.
  
  
  CONCLUSIONS
  Findings suggest that formalin inactivated Indian WNV strain has a good immunogenic potential. This is the first study on assessment of immunogenic potential of a lineage 5 strain of WNV. Our study reveals that it would be a promising and effective candidate for vaccine studies which warrants further evaluation.
authors.affiliation: Regional Medical Research Centre, ICMR (NE Region), Dibrugarh, Assam, India; Centre for studies in Biotechnology, Dibrugarh University, Dibrugarh-786004, Assam, India.
authors.forename: Pritom
authors.initials: P
authors.lastname: Chowdhury
authors.affiliation: Regional Medical Research Centre, ICMR (NE Region), Dibrugarh, Assam, India. Electronic address: sirajkhanicmr@gmail.com.
authors.forename: Siraj
authors.initials: S
authors.lastname: Ahmed Khan
authors.affiliation: Regional Medical Research Centre, ICMR (NE Region), Dibrugarh, Assam, India; Centre for studies in Biotechnology, Dibrugarh University, Dibrugarh-786004, Assam, India.
authors.forename: Rashmee
authors.initials: R
authors.lastname: Topno
authors.affiliation: Regional Medical Research Centre, ICMR (NE Region), Dibrugarh, Assam, India.
authors.forename: Prafulla
authors.initials: P
authors.lastname: Dutta
authors.affiliation: Centre for studies in Biotechnology, Dibrugarh University, Dibrugarh-786004, Assam, India.
authors.forename: R N S
authors.initials: RN
authors.lastname: Yadav
authors.affiliation: Regional Medical Research Centre, ICMR (NE Region), Dibrugarh, Assam, India.
authors.forename: Jagadish
authors.initials: J
authors.lastname: Mahanta
keywords: Assam; Cytokine; Efficacy; Immunization; Neutralizing antibody; West Nile virus