Codon optimization of antigen coding sequences improves the immune potential of DNA vaccines against avian influenza virus H5N1 in mice and chickens

Abstract

BackgroundHighly pathogenic avian influenza viruses are a serious threat to domestic poultry and can be a source of new human pandemic and annual influenza strains. Vaccination is the main strategy of protection against influenza, thus new generation vaccines, including DNA vaccines, are needed. One promising approach for enhancing the immunogenicity of a DNA vaccine is to maximize its expression in the immunized host.MethodsThe immunogenicity of three variants of a DNA vaccine encoding hemagglutinin (HA) from the avian influenza virus A/swan/Poland/305-135V08/2006 (H5N1) was compared in two animal models, mice (BALB/c) and chickens (broilers and layers). One variant encoded the wild type HA while the other two encoded HA without proteolytic site between HA1 and HA2 subunits and differed in usage of synonymous codons. One of them was enriched for codons preferentially used in chicken genes, while in the other modified variant the third position of codons was occupied in almost 100 % by G or C nucleotides.ResultsThe variant of the DNA vaccine containing almost 100 % of the GC content in the third position of codons stimulated strongest immune response in two animal models, mice and chickens. These results indicate that such modification can improve not only gene expression but also immunogenicity of DNA vaccine.ConclusionEnhancement of the GC content in the third position of the codon might be a good strategy for development of a variant of a DNA vaccine against influenza that could be highly effective in distant hosts, such as birds and mammals, including humans.Electronic supplementary materialThe online version of this article (doi:10.1186/s12985-016-0599-y) contains supplementary material, which is available to authorized users.

Peer Review #1 of "Codon optimization, expression in Escherichia coli, and immunogenicity analysis of deformed wing virus (DWV) structural protein (v0.1)"

“…Comparing the codon usage in E. coli, we found many rare codons in the wild DWV structural protein genes, and CAI values of the three target genes were only approximately 0.2; this likely results in lower expression yields-even expression failure -in E. coli. Codon optimization can improve protein production via optimization of translation elongation, and previous reports have shown that a codon-optimization strategy can improve the expression level of genes in many species (Chu et al, 2018;Hu et al, 2019;Nieuwkoop et al, 2019;Sun et al, 2017). In this study, the rare codons of DWV VP1, VP2, and VP3 were replaced with the most highly preferred codons, and the GC content was changed to approximately 70%.…”

“…Research has indicated that structural proteins of the virus not only play an important role in viral invasion and replication but also have excellent immunogenicity and that they are frequently selected as candidates for the development of therapeutic antibodies (Huo et al, 2018;Li et al, 2014;Stachyra et al, 2016;Wang et al, 2017). Compared with vertebrate immune systems, honey bee immune pathways lack acquired immunity (Bull et al, 2012) and cannot directly generate specific antibodies in response to an antigen.…”

“…According to a previously reported method, IgG levels in mice sera were detected using ELISA (Stachyra et al, 2016). In brief, microtiter plates (Corning, USA) were coated with 50 μL of the purified virus particles/well at a concentration of 5 μg/mL at 4°C overnight.…”

Engineering DNA vaccines against infectious diseases

“…During the plasmid design, low-frequency eukaryotic codons in the foreign DNA backbone are identified and replaced for high-frequency codons, while still maintaining their respective coded amino acids [130][131][132]. There has been recent progress in terms of enhancing the immunogenicity in mice and chicken primed with such codon-optimized DNA vaccines [133][134][135].…”

Characterization of mAb6-9-1 monoclonal antibody against hemagglutinin of avian influenza virus H5N1 and its engineered derivative, single-chain variable fragment antibody

“…HI tests were performed as described previously (Stachyra et al, 2014;Stachyra et al, 2016) Antibodies. IgY 745 -anty-H5 HA (H5N1) polyclonal IgY was purified in our laboratory from eggs collected from laying hens immunized with DNA vaccine based on pCI vector with cloned cDNA sequence encoding 1-568 aa of HA from A/swan/Poland/305-135V08/2006 (H5N1) (Stachyra et al, 2014).…”