The Inhibitory Effect of Camel Lactoferrin-chimera, a Recombinant Antimicrobial Peptide, on Avian Influenza Virus Subtype H9N2

Background: Avian influenza subtype H9N2 is poultry’s most prevalent influenza virus worldwide. It imposes economic losses to the poultry industry and has zoonotic potential. Currently, the two main groups of anti-influenza drugs are adamantanes and neuraminidase inhibitors. In recent years, there has been an increase in the resistance to existing anti-influenza drugs. Antimicrobial peptides are a group of potential drug candidates with broad-spectrum activity. Camel lactoferrin (cLF)-chimera is an antimicrobial peptide synthesized from camel milk lactoferrin. Objectives: This study aims to evaluate the inhibitory effects of cLF-chimera on avian influenza, subtype H9N2. Methods: One hundred and seventy 11-day-old specific pathogen-free (SPF) embryonated eggs were randomly distributed into 17 groups. Different virus and peptide concentrations were injected into the eggs. The eggs were incubated for four days, and daily candling was done for viability assessment. On the 4th day of incubation, each group’s live or dead embryos were sorted and evaluated for gross anomalies. Next, for histopathological analysis, chick embryos were fixed with 10% neutral buffered formalin for one week. The 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) assay was performed to determine peptide and virus concentrations. Results: Embryo viability results and macroscopic and histopathologic findings showed that the peptide had inhibitory effects against the virus. These results are consistent with the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide) (MTT) assay. Moreover, the peptide has proven effects against pathogenic bacteria, which can be advantageous compared to common anti-influenza medications. Conclusion: According to the results, cLF-chimera has an inhibitory effect on the H9N2 influenza virus.