An inactivated West Nile Virus vaccine derived from a chemically synthesized cDNA system

Abstract

A cDNA comprising the complete genome of West Nile Virus (WNV) was generated by chemical synthesis using published sequence data, independent of any preformed viral components. The synthetic WNV, produced by transfection of in vitro transcribed RNA into cell culture, exhibited undistinguishable biological properties compared to the corresponding animal-derived wild-type virus. No differences were found concerning viral growth in mammalian and insect cell lines and concerning expression of viral proteins in cells. There were also no significant differences in virulence in mice following intranasal challenge. After immunizations of mice with experimental vaccines derived from the synthetic and wild-type viruses, protection from lethal challenge was achieved with similar amounts of antigen. Both vaccine preparations also induced comparable levels of neutralizing antibodies in mice. In addition, the synthetic approach turned out to be very accurate, since the rescued WNV genome contained no undesired mutations. Thus, the first flavivirus based on chemical gene synthesis was indistinguishable from the parent virus. This demonstrates that virus isolates from animal sources are dispensable to derive seed viruses for vaccine production or research.

Increasing West Nile virus antibody titres in central European plasma donors from 2006 to 2010

“…We therefore analysed the antibody specificity of six randomly selected IVIG lots, produced in 2007 (n=1) and 2009 (n=5), by Western blot. TBEV-or WNV-infected Vero cells as well as recombinant WNV NS1 antigen were used as a positive and uninfected Vero cells as a negative control [37,38]. The blots were incubated with IVIG produced from plasma collected in Austria, Germany and the Czech Republic (Figure 2A), or with a control serum from TBEV-infected mice ( Figure 2B).…”

Current trends in West Nile virus vaccine development

“…A formalin-inactivated vaccine based on a pathogenic lineage 1 strain of WNV (ISR98) has also been described, and was shown to be protective in a goose challenge model [103]. Two other groups have developed formalin-inactivated vaccines, both based on the virulent WNV-NY99 strain of virus [104,105]. In one study, mice immunized with a two-dose schedule (1 μg per dose, alum-adjuvanted) achieved virus neutralizing titers of ~1:250 against WNV-NY99 at two weeks after final vaccination and were protected from intranasal challenge with virulent WNV [105].…”

“…Two other groups have developed formalin-inactivated vaccines, both based on the virulent WNV-NY99 strain of virus [104,105]. In one study, mice immunized with a two-dose schedule (1 μg per dose, alum-adjuvanted) achieved virus neutralizing titers of ~1:250 against WNV-NY99 at two weeks after final vaccination and were protected from intranasal challenge with virulent WNV [105]. In a second study, mice were also given a two-dose schedule of experimental, non-adjuvanted vaccine provided by the Research Foundation for Microbial Diseases of Osaka University (BIKEN, Osaka, Japan) [104].…”

Synthetic Poliovirus and Other Designer Viruses: What Have We Learned from Them?

“…These complications can be avoided if the starting material can be synthesized de novo, allowing for a "clean start" of vaccine development. Orlinger et al (94) have chosen this strategy for the production of WNV seed stocks. They have produced the 11,029-nt-long WNV genome sequence by chemical genome synthesis, using the known genome sequence that differed from that of the wild-type virus by only three silent mutations (introduced for cloning purposes).…”

“…Typically, biological organization is altered to generate new physiological networks that perform functions hitherto thought unachievable. According to this definition, the poliovirus synthesis of 2002 (20) does not belong into the category of synthetic biology, and neither does the de novo construction of X174 (122) or of West Nile Fever virus (94). The syntheses of the 1918 Spanish influenza and the HERV-K retrovirus served to resurrect these infectious agents (as closely to reality as possible) with the hope of unraveling their properties, while the construction of SIVcpz and Bat SCoV was used to identify trans-species movement resulting in the evolution of deadly human pathogens.…”