Live-Attenuated Influenza Vaccine

Polymun has established a nasal spray vaccine employing live attenuated influenza strains we call Vero-Vac. It is produced by our proprietary, animal-component free cell culture technology using the Vero cell line.

The concept of attenuating influenza strains at low temperature was carried out using Vero cell culture instead of fertilized hen eggs. In serial passages of both influenza A and B viruses in Vero cells at 25°C several mutations were introduced leading to our donor or master strains. Subsequently, the vaccine strains are created by genetic reassortment of the two genes coding for the surface antigens hemagglutinin and neuraminidase from the contemporary wild type strain and all other genes from the cold adapted, attenuated proprietary master strain. Due to this composition the vaccine strains acquire the attenuation with the temperature sensitive and cold adapted phenotype from the master strain, but at the same time display the antigenic properties of the contemporary pathogenic virus strain.

The whole process of creating and producing the strains is done using the Vero cell line. This African green monkey kidney cell line has already been accepted for the production of other live and inactivated vaccines. Polymun has developed a completely defined, animal-component-free cultivation system, thus providing additional safety in combination with excellent economy. The use of a continuous primate cell line does not only improve safety and scalability of the production process, but also generates viruses that reflect better their epidemic counterparts than egg produced strains.

The live attenuated influenza vaccine is administered intranasally as a spray thus mimicking the natural way of infection. A clinical trial comparing it to the successful Russian vaccine of the similar type (produced in fertilized hen eggs) was performed with encouraging results.

In addition, the next generation of influenza vaccines is already under development at Polymun. It is based on the attenuation of influenza viruses by engineering the NS gene. This approach creates a new type of live attenuated influenza vaccines and viral vectors. We already demonstrated in mice the possibility to modulate influenza virus pathogenicity by truncation of the NS1 protein. Moreover, hyperattenuated and replication-deficient NS mutants used as intranasal vaccines showed the same protection against the virulent virus challenge in the same way as normally replicating vaccines did. The truncated NS1 proteins stimulate the immune response by inducing the release of interferon, pro-inflammatory cytokines and chemokines. We believe the NS gene technology will not only provide an interesting alternative to the current approaches for live influenza vaccines but can also function as carrier of foreign antigens in the NS1 reading frame.

Polymun is looking for an investor who wants to continue with this technology.

Patents:

Live vaccine and method of manufacture
granted by: AU 2002223560; CN ZL01819206.8; EP 1 358 319 (AT BE CH/LI CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE SI TR); US 7,494,659
pending in: CA, JP, KR

Recombinant influenza A viruses
granted by: AU 2001250352; EP 1 259 629 (AT BE CH/LI DE FR GB IT NL); RU 2280690; US 6,800,288
pending in: international stage WO0164860

Publications:

Stasakova J, Ferko B, Kittel C, Sereinig S, Romanova J, Katinger H, Egorov A (2005) Influenza A mutant viruses with altered NS1 protein function provoke caspase-1 activation in primary human macrophages, resulting in fast apoptosis and release of high levels of interleukins 1beta and 18. J Gen Virol 86(1):185-95

Ferko B, Stasakova J, Romanova J, Kittel C, Sereinig S, Katinger H, Egorov A (2004) Immunogenicity and protection efficacy of replication-deficient influenza A viruses with altered NS1 genes. J Virol 78(23):13037-45

Romanova J, Katinger D, Ferko B, Vcelar B, Sereinig S, Kuznetsov O, Stukova M, Erofeeva M, Kiselev O, Katinger H, Egorov A (2004) Live cold-adapted influenza A vaccine produced in Vero cell line. Virus Res 103(1-2):187-93

Mochalova L, Gambaryan A, Romanova J, Tuzikov A, Chinarev A, Katinger D, Katinger H, Egorov A, Bovin N (2003) Receptor-binding properties of modern human influenza viruses primarily isolated in Vero and MDCK cells and chicken embryonated eggs. Virology 313(2):473-80

Romanova J, Katinger D, Ferko B, Voglauer R, Mochalova L, Bovin N, Lim W, Katinger H, Egorov A (2003) Distinct hostrange of influenza H3N2 virus isolates in Vero and MDCK cells is determined by cell specific glycosylation pattern. Virology 307(1):90-7

Garcia-Sastre A, Egorov A, Matassov D, Brandt S, Levy DE, Durbin JE, Palese P, Muster T (1998) Influenza A virus lacking the NS1 gene replicates in interferon-deficient systems. Virology 252(2):324-30

Egorov A, Brandt S, Sereinig S, Romanova J, Ferko B, Katinger D, Grassauer A, Alexandrova G, Katinger H, Muster T (1998) Transfectant influenza A viruses with long deletions in the NS1 protein grow efficiently in Vero cells. J Virol 72(8):6437-41