Research and Development on Hydro Pericardium Syndrome virus vaccine

Research and Development on Hydro Pericardium Syndrome virus vaccine
M. Salah-ud-Din Shah, DVM, M.Sc. (Hons)
Biological Chemistry Division, NIAB
INTRODUCTION
Hydropericardium Syndrome is a viral disease of poultry caused by Avi Adeno virus- 4 (Rabbani et al., 1998)
It was first observed in 1987 at Angara goth, a broiler growing area near Karachi, Pakistan. So the syndrome was named as Angara disease (Jaffery, 1988).
This disease causes heavy losses every year, mortality rate is 50-70%
Vaccine available in market is 25% of total population (170 M)
STATUS OF AVAILABLE VACCINES
At present vaccines available in market are produced from crude methods e.g. formalized liver homogenate, these vaccines have following short comings
They carry proteins of livers
Pathogens other than adeno virus if birds are infected
These vaccines have very short shelf life (only 2-3 months)
Vaccine failure is very common
PREVIOUS WORK
Vaccine is Produced from crude method with slight modifications
Virus is extracted & purified by centrifugation
Contains no liver protein
Monitoring of chicks for any other disease to avoid other pathogens
Addition of antibiotics to increase shelf life for one year
Addition of Vitamin E and Selenium
Marker
1
2
3
4
6
116 kDa
66.2 kDa
45 kDa
35 kDa
25 kDa
14.4 kDa
18.2 kDa
No. of Daily Mortalities in infected flock after vaccination
Weakly Antibody titer of broilers after vaccination in treated & control group
Brochure of HPS Vaccine
PLAN OF WORK
Following techniques can be used for production of standard vaccine
Cell culture based vaccine production
DNA recombinant vaccine production
Trials of both vaccines and comparison through ELISA
CELL CULTURE BASED VACCINE
This virus can be grown on chicken hepatocytes cultured in vitro by following steps (Hess et al. 1998)
Culturing of primary chicken hepatocytes in cell culture media (M - 199) to obtain monolayer in cell culture flasks
Inoculation of adeno virus on monolayer of cells and allow the virus to grow on cells
Extraction of virus from cells after observing cytopathic effects, quantification by ELISA, then use this virus as antigen in vaccine
DNA RECOMBINANT VACCINE
Extraction of viral DNA from samples of infected chicks (Kao et al. 2000)
Amplification of HPS virus surface antigen gene by PCR (Jiang et al.,1999)
Ligate HPS virus surface antigen gene in cloning vector
Transform ligated Product in E. coli
Screen and select the recombined clone
Confirm the clone by running the sample on 1% agarose gel
DNA sequencing
Detect the cloned protein by ELISA.
Selected cloned colony will be used for antigen in vaccine production
EVALUATION OF VACCINES
Trials of both vaccines will be done by vaccinating the birds first on small scale then on large scale in field conditions
Collection of serum samples from vaccinated birds
ELISA will be performed at end for determination of antibody titers to evaluate both vaccines (Dawson et al., 1998)
Thanks