Production of recombinant fowl pox vaccine expressing Haemagglutinin of Avian Influenza H5N1

Introduction:

Avian influenza (AI) is an infectious disease caused by Avian Influenza virus (AIV), which is divides in to 16 Heamagglutinin (HA) subtypes and 9 Neuraminidases (NA) subtypes on the bases of antigenicity of HA and NA surface glycoprotein. H5 and H7 may cause High Pathogenic Avian Influenza (HPAI). Out breaks of severe disease caused by influenza virus have been reported frequently in the recent years, leading to substantial economic losses. H5N1 strain can de transmitted directly from birds to human (1-2) H7 and H9 AIV have been identified from humans and other mammals. These facts have made clear the zoonotic importance of the Avian Influenza virus. Presently H5 and H7 (HPAI) remain active in the south Asia and other part of the world (3-4). From Pakistan H9N2 (5), H7N3 have been isolated a no of time and in 2006 H5N1 was reported. Now in 2007 there is a severe outbreak of H5N1 in Islamabad and different districts of Punjab.

Objectives:

To produce avian influenza H5 vaccine, recombinant with Fowl Pox virus (FPV). Currently, inactivated whole vaccines are used which are creating problems in Epidemiological studies and it is difficult to differentiate between vaccinal response and outbreak from serological studies (6).

Methodology:

Avian Influenza virus will be isolated from field or RNA will be isolated from inactivated whole H5 subtype vaccine, cDNA encoding whole H5 genes of H5N1 subtype will be cloned and introduce into expression vector plasmid. The plasmid will be introduced in Fowl Pox virus attenuated strain; the recombinant Fowl pox virus will be propagated in Chicken Embryo Fibroblast (CEF) to produce vaccine. Expression of H5 gene in the virus will be detected by PCR using specific primers. Immunity produced in the experimental birds will be titrated by Haemagglutination Inhibition (HI) test and experimental inoculation of H5N1 virus to the birds.

References:

1. Subbarao K, Klimov A, Katz J, Regnery H, Lim W, Hall H, et al. Characterization of an avian influenza A (H5N1) virus isolated from a child with a fatal respiratory illness. Science 1998; 279:393–6.

2. Claas EC, de Jong JC, van Beek R, Rimmelzwaan GF, Osterhaus AD. Links Human influenza virus A/Hong Kong/156/97 (H5N1) infection. Vaccine 1998; 16:977–88.

3. Spackman E, Senne DA, Davison S, Suarez DL. Sequence analysis of recent H7 avian influenza viruses associated with three different outbreaks in commercial poultry in the United States. J Virol 2003; 77:13399–402.

4. Fouchier RAM, Schneeberger PM, Rozendaal FW, Broekman JM, Kemink SAG, Munster V, et al. Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. PNAS 2004; 101:1356–61.

5. Naeem, K., A. Ullah, R. J. Manvell and D. J. Alexander, 1999. Avian influenza A subtype H9N2 in poultry in Pakistan. Vet. Rec., 145: 560.

6. Beard CW, Schnitzlein W, Mand Tripathy DN. Protection of chickens against highly pathogenic avian influenza virus (H5N2) by recombinant fowlpox viruses. Avian Diseases 1991; 35:356–9.