行政院國家科學委員會專題研究計畫成果報告:豬繁殖與呼吸道症候群及假性犬病複合疫苗之開發(III)

Constructed chimeric viruses, PR-PRRS-ORF3,
PR-PRRS-ORF5, PR-PRRS-ORF3 + PR-PRRS- ORF
5and commercial PR (pseudorabies) and PRRS
(porcine reproductive and respiratory syndrome)
vaccines were used to vaccinate piglets to test their
immunogenicity against PRRS virus. Totally 27
piglets at 5 weeks of age without PR and PRRS
antibody were divided into 6 groups; The first three
groups, 6 for each were inoculated with PR-PRRS
-ORF3, PR-PRRS-ORF5 and PR-PRRS-ORF3 +
PR-PRRS-ORF5 chimeric viruses (105 TCID50 /ml)
respectively. The rest three groups, 3 for each were
inoculated with commercial PR and PRRS and PBS
respectively, served as positive and negative control
group. All piglets were challenged intra nasally
with virulent PRRS-F1 virus (105.5TCID50/ml) at 4
weeks after vaccination. Clinical manifestations and
rectal temperature were daily recorded. Blood
samples were collected before and 2, 4 weeks after
vaccination, before and 2, and 4 weeks after challenge.
Clinically all experimental pigs did not show any
abnormal signs after vaccination with either
constructed chimeric virus or commercial PR and
PRRS vaccines. In temperature response, 2 out of 6 of
PR-PRRS-ORF3 vaccinated group showed rise in
temperature 40.2-40.5 0C at 5 days after challenge.
Commercial PR and PRRS vaccines vaccinated group,
1 for each group showed rise in temperature 40.1-40.2
0C at the day 6 after challenge. In negative control
group, 2 of 3 had temperature 40.3-40.5 0C. Sero-
logically, all sera collected at pre-vaccinated and 2
weeks after vaccination showed antibody titer less
than 2X against PR and PRRS. In PR-PRRS-ORF5,
PR-PRRS-ORF3 + PR-PRRS-ORF5 and commercial
PRRS vaccine vaccinated groups, 2 out of 6, 2 out of
6 and 2 out of 3 respectively showed antibody titer
2X against PRRS. However, the rest of piglets still
showed no antibody activity. Among PR-PRRSORF5,
PR-PRRS-ORF3 + PR-PRRS-ORF5 and
commercial PRRS vaccine vaccinated groups showed
significantly rise in antibody titers ranging from 2X to
8X at 2 weeks after challenge with PRRS-F1 virus.
Pigs in the rest groups showed no rise in antibody
titer at 2 weeks after challenge. In the aspect of PR
antibody response, all pigs showed no antibody titer
against PR at 2 weeks after vaccination. However, 2
out of 6 in each group of PR-PRRS-ORF3,
PR-PRRS-ORF5 and PR-PRRS-ORF3 + PR-PRRS
-ORF5 vaccinated pigs had antibody titer 2X against
PR at 4 weeks after vaccination. For the commercial
PR vaccine vaccinated pigs, 2 out of 3 had antibody
titers 2X-4X against PR at 4 weeks after vaccination.
Antibody titers against PR of all vaccinated pigs did
not show any significant rise thereafter.