Vaccination of pigs with a recombinant porcine adenovirus expressing the gD gene from pseudorabies virus.
Five week old, commercially available large white pigs were vaccinated with either a single dose or two doses of a recombinant porcine adenovirus expressing the glycoprotein D gene from pseudorabies virus (PRV). Pigs were monitored for the development of serum neutralizing antibodies to PRV and challenged 3 weeks after final vaccination. Prior to challenge, pigs given 2 doses of the vaccine demonstrated boosted levels of antibody compared with those given a single dose, and all surviving pigs had increased neutralization titres over pre-challenge levels. Following challenge, pigs were monitored for clinical signs of disease, with blood and nasal swabs collected for virus isolation. All control animals became sick with elevated temperatures for 6 days post challenge, whereas; vaccinated animals displayed an increase in body temperature for only 2-3 days. Control pigs and those given a single dose all lost condition, but the group given 2 doses remained healthy. At postmortem, gross lesions of pneumonia only occurred in control animals and those given a single dose of vaccine. Histology carried out on the brains of all animals demonstrated a difference in severity of infection and frequency of immunohistochemical antigen detection between test animals, with control and single dose groups being most severely affected and pigs given 2 doses the least. Virus isolation studies demonstrated that no viraemia could be detected, but virus was found in nasal swabs from some animals in both groups of vaccinates following challenge.
Hammond
J M
JM
CSIRO, Livestock Industries, Private Mail Bag 24, Australian Animal Health Laboratory, Geelong, Victoria 3220, Australia.
Jansen
E S
ES
Morrissy
C J
CJ
van der Heide
B
B
Goff
W V
WV
Williamson
M M
MM
Hooper
P T
PT
Babiuk
L A
LA
Tikoo
S K
SK
Johnson
M A
MA
D000256:Adenoviridae / Q000235:genetics* / Q000276:immunology; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002460:Cell Line; D011558:Herpesvirus 1, Suid / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D007115:Immunization Schedule; D009500:Neutralization Tests; D011557:Pseudorabies / Q000401:mortality / Q000473:pathology / Q000517:prevention & control*; D022421:Pseudorabies Vaccines / Q000235:genetics / Q000627:therapeutic use*; D013552:Swine; D019444:Vaccines, DNA / Q000627:therapeutic use*; D014759:Viral Envelope Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000276:immunology
D000914:Antibodies, Viral; D022421:Pseudorabies Vaccines; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; C107752:glycoprotein D, pseudorabies virus