Immunoinformatics Approach for Design and Evaluation of Multi-Epitope Based Vaccine Against Avian Influenza Virus H9N2

Abstract

Avian Influenza virus is a negative sense single stranded RNA virus, and it is the main causative agent of AI infection in chickens. Despite the availability of commercial antiviral drugs, live attenuated vaccine and killed vaccines, the outbreaks are common in poultry industry causing huge economic losses. The main factors responsible for the drugs and vaccine ineffectiveness are high mutation rate, genetic variability of the virus and other factors causing immunosuppression in birds. In this study, two approaches were adopted to prevent the spread and infection of AIV H9N2. In first portion, Thiazolidine derivatives were assessed for their antiviral potential against AIV H9N2 by inoculating them along with virus into 8-10 days old chicken embryonated eggs. Further, virus titer was calculated by Hemagglutination assay. In second portion, a multi- epitope vaccine was developed using computational and Immunoinformatics approach against AIV H9N2 based on the sequences reported from Pakistan. Due to major role in virus attachment, entry and infection in host cell, prioritized epitopes were predicted from surface glycoproteins proteins Hemagglutinin and Neuraminidase using best substitute human alleles for chicken. These non-host homologous epitopes were capable of inducing strong B cell, CTLs, HTLs, and IFN- γ response against the virus. At N terminal of the vaccine construct, an adjuvant (Avian β defensin 6) was added to enhance the immunogenicity of the construct. This construct was then modeled, refined, and evaluated using online tools. Gallus gallus chTLR3, chTLR7 and chTLR21 demonstrated a significant binding relationship and stability with multi-epitope vaccine construct. Codon optimization of the vaccine construct was done for expression in E. coli K12 system before cloning into the pET-28a (+) vector. This research lays the groundwork for introducing new drugs and developing vaccine against AIV H9N2 that is both safe and effective.