Vaccine vectors
Dr Mike Skinner’s ‘Vaccine Vector Group’ works on the improvement of avian poxviruses as recombinant vaccine vectors (funded by the BBSRC). Their studies are relevant to vaccination of poultry (using avian influenza as a model target) and mammals, including humans. Developments are based on improving our understanding of how the avian poxviruses interact with and modulate the innate immune responses of permissive (avian) and non-permissive (mammalian) hosts. In addition, our relatively poor understanding of the avian type I interferon system is addressed directly in a collaborative study with Prof Steve Goodbourn (St George’s University of London).
Avian poxviruses (Avipoxviruses)
Poxvirus infections have been described in more than 230 species of birds yet little is known about the genome diversity and host-range specificity of the causative agent(s). The only members to have been the focus of significant study are Fowlpox virus (FWPV) and, to a lesser extent, Canarypox virus (CNPV).
Fowlpox virus
FWPV, type species of the Avipoxviruses, is a pathogen of chickens and turkeys. It has one of the largest viral genomes. The sequences of a virulent US FWPV (288 kbp; (Afonso et al., 2000)) and an attenuated vaccine strain, FP9 (266 kbp; (Laidlaw & Skinner, 2004)), have been determined.
Following the early introduction of vaccines, beginning from the 1930’s, fowlpox has for quarter of a century been effectively controlled in temperate climates but remains problematic in tropical and sub-tropical climates where insect control becomes difficult (FWPV can be transmitted passively by biting insects).
Upper panel: FWPV virions labelled with fluorescent antibody (green) against the 63 kDa ATI-like protein (Boulanger et al., 2002) in two adjacent infected cells surrounded by uninfected cells. DNA in the cell nuclei and viral factories is labelled blue.
Lower panel: Electron micrograph showing three FWPV particles at different stages of morphogenesis, from immature (right) to mature budding particle with classic dumbbell appearance (left)
Fowlpox virus immunomodulation
Our major interest in FWPV lies in its complexity (it has more than 250 genes) and its ability to resist the ‘innate’ immune responses of the host chicken. Even with the genetic sequence available, the mechanisms by which this resistance occurs remain obscure. Viral homologues of TGFbeta and IL18-binding protein are liable to be involved, as are four CC chemokine-like proteins (Jeshtadi et al., 2005). Peter Staeheli’s group in Freiburg identified FPV016 as encoding a novel binding protein for interferon gamma (Puehler et al., 2003). We have recently identified genes encoding two novel modulators of avian type I interferon.
Fowlpox virus as recombinant vaccine vector
FWPV was initially developed as a recombinant vaccine vector for use in poultry (Skinner et al., 2005). Since 1995, more than 2 billion doses of a commercially licensed avian influenza H5 recombinant Fowlpox virus have been used to control avian influenza in Mexico (Bublot et al., 2010), and more recently in S E Asia.
The ability of Fowlpox virus to enter mammalian cells and express proteins whilst being unable to replicate (Somogyi et al., 1993) led to its development as a safe recombinant vaccine vector for use in mammals, including humans (Taylor et al., 1988). With our collaborators, we have shown that FWPV can deliver antigen to human dendritic cells and stimulate class I-restricted T-cell activity in vitro and in vivo (Brown et al., 1999; Brown et al., 2000; Vazquez Blomquist et al., 2002). Overshadowed for some time by another avipoxvirus vector, CNPV (Taylor et al., 1992), and by modified vaccinia viruses (Paoletti, 1996), such as MVA, FWPV has made a comeback with the recognition that it can serve as a potent partner with MVA in prime-boost regimes. This has been demonstrated by preclinical and Phase I trials (plus subsequent challenge studies) with an FWPV recombinant expressing malaria antigens by our collaborators in Oxford (Anderson et al., 2004; Webster et al., 2005). Trials have also been conducted in the Gambia (Moorthy et al., 2004).
CNPV recombinants are licensed for use in horses and companion animals in the US and the EU, against diseases such as West Nile fever, equine influenza and canine distemper. CNPV recombinants have also been trialled in humans, most notably, in combination with recombinant glycoprotein 120, against HIV in Thailand (Rerks-Ngarm et al., 2009).
Avian Type I Interferon
Although the antiviral action of interferon was first discovered in the avian system by Isaacs in 1957, much of the subsequent study on interferon was naturally conducted on the mammalian system. Indeed the genes encoding chicken interferon were only discovered in 1994. The draft assembly of the chicken genome sequence helped in identifying key differences between avian and mammalian systems. There is still a considerable gap in our knowledge of the avian interferon system and in the availability of reagents for its study, undermining our ability to understand the emergence of important human pathogens like West Nile fever virus and the possible emergence of a human pandemic virus from highly pathogenic avian influenza H5N1 virus.
References with links:
Afonso, C. L., Tulman, E. R., Lu, Z., Zsak, L., Kutish, G. F. & Rock, D. L. (2000). The genome of fowlpox virus. J Virol 74, 3815-3831. http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://jvi.asm.org/cgi/content/full/74/8/3815
Anderson, R. J., Hannan, C. M., Gilbert, S. C., Laidlaw, S. M., Sheu, E. G., Korten, S., Sinden, R., Butcher, G. A., Skinner, M. A. & Hill, A. V. (2004). Enhanced CD8+ T cell immune responses and protection elicited against Plasmodium berghei malaria by prime boost immunization regimens using a novel attenuated fowlpox virus. J Immunol 172, 3094-3100. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14978115
Brown, M., Davies, D. H., Skinner, M. A., Bowen, G., Hollingsworth, S. J., Mufti, G. J., Arrand, J. R. & Stacey, S. N. (1999). Antigen gene transfer to cultured human dendritic cells using recombinant avipoxvirus vectors. Cancer Gene Ther 6, 238-245. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=0010359209
Brown, M., Zhang, Y., Dermine, S., de Wynter, E. A., Hart, C., Kitchener, H., Stern, P. L., Skinner, M. A. & Stacey, S. N. (2000). Dendritic cells infected with recombinant fowlpox virus vectors are potent and long-acting stimulators of transgene-specific class I restricted T lymphocyte activity. Gene Ther 7, 1680-1689. http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?db=m&form=6&dopt=r&uid=0011083477
Bublot, M., Manvell, R. J., Shell, W. & Brown, I. H. (2010). High level of protection induced by two fowlpox vector vaccines against a highly pathogenic avian influenza H5N1 challenge in specific-pathogen-free chickens. Avian Dis 54, 257-261. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=20521642
Jeshtadi, A., Henriquet, G., Laidlaw, S. M., Hot, D., Zhang, Y. & Skinner, M. A. (2005). In vitro expression and analysis of secreted fowlpox virus CC chemokine-like proteins Fpv060, Fpv061, Fpv116 and Fpv121. Arch Virol 150, 1745-1762. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15931460
Laidlaw, S. M. & Skinner, M. A. (2004). Comparison of the genome sequence of FP9, an attenuated, tissue culture-adapted European strain of Fowlpox virus, with those of virulent American and European viruses. J Gen Virol 85, 305-322. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=14769888
Moorthy, V. S., Imoukhuede, E. B., Keating, S., Pinder, M., Webster, D., Skinner, M. A., Gilbert, S. C., Walraven, G. & Hill, A. V. (2004). Phase 1 evaluation of 3 highly immunogenic prime-boost regimens, including a 12-month reboosting vaccination, for malaria vaccination in Gambian men. J Infect Dis 189, 2213-2219. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15181568
Paoletti, E. (1996). Applications of pox virus vectors to vaccination: an update. Proc Natl Acad Sci U S A 93, 11349-11353
Puehler, F., Schwarz, H., Waidner, B., Kalinowski, J., Kaspers, B., Bereswill, S. & Staeheli, P. (2003). An interferon-gamma-binding protein of novel structure encoded by the fowlpox virus. J Biol Chem 278, 6905-6911. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12486029
Rerks-Ngarm, S., Pitisuttithum, P., Nitayaphan, S., Kaewkungwal, J., Chiu, J., Paris, R., Premsri, N., Namwat, C., de Souza, M., Adams, E., Benenson, M., Gurunathan, S., Tartaglia, J., McNeil, J. G., Francis, D. P., Stablein, D., Birx, D. L., Chunsuttiwat, S., Khamboonruang, C., Thongcharoen, P., Robb, M. L., Michael, N. L., Kunasol, P. & Kim, J. H. (2009). Vaccination with ALVAC and AIDSVAX to prevent HIV-1 infection in Thailand. N Engl J Med 361, 2209-2220. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=19843557
Skinner, M. A., Laidlaw, S. M., Eldaghayes, I., Kaiser, P. & Cottingham, M. G. (2005). Fowlpox virus as a recombinant vaccine vector for use in mammals and poultry. Expert Rev Vaccines 4, 63-76. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15757474
Somogyi, P., Frazier, J. & Skinner, M. A. (1993). Fowlpox virus host range restriction: gene expression, DNA replication, and morphogenesis in nonpermissive mammalian cells. Virology 197, 439-444. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8212580
Taylor, J., Weinberg, R., Languet, B., Desmettre, P. & Paoletti, E. (1988). Recombinant fowlpox virus inducing protective immunity in non-avian species. Vaccine 6, 497-503
Taylor, J., Weinberg, R., Tartaglia, J., Richardson, C., Alkhatib, G., Briedis, D., Appel, M., Norton, E. & Paoletti, E. (1992). Nonreplicating viral vectors as potential vaccines: recombinant canarypox virus expressing measles virus fusion (F) and hemagglutinin (HA) glycoproteins. Virology 187, 321-328
Vazquez Blomquist, D., Green, P., Laidlaw, S. M., Skinner, M. A., Borrow, P. & Duarte, C. A. (2002). Induction of a strong HIV-specific CD8+ T cell response in mice using a fowlpox virus vector expressing an HIV-1 multi-CTL-epitope polypeptide. Viral Immunol 15, 337-356. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=12081016
Webster, D. P., Dunachie, S., Vuola, J. M., Berthoud, T., Keating, S., Laidlaw, S. M., McConkey, S. J., Poulton, I., Andrews, L., Andersen, R. F., Bejon, P., Butcher, G., Sinden, R., Skinner, M. A., Gilbert, S. C. & Hill, A. V. (2005). Enhanced T cell-mediated protection against malaria in human challenges by using the recombinant poxviruses FP9 and modified vaccinia virus Ankara. Proc Natl Acad Sci U S A. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15781866
