2.8 Immunogenicity of PRV isolate
As
the representative PRV isolate, NY isolate was inoculated into ST cells.
The cell culture suspension was inactivated by incubating with moderate
formalin (Sigma-Aldrich) at 37℃ for 24 h, and then emulsified with
Freund’s complete adjuvant and
Freund’s incomplete adjuvant,
respectively. 60 six-week-old healthy BALB/c female mice were randomly
divided into four groups of 15 mice each. Mice in Group 1 were injected
with 0.5 mL of NY isolate containing Freund’s complete adjuvant in
1th week, followed by injecting with equal volume of
emulsifier with Freund’s incomplete adjuvant in 3thweek, and finally with the inactivated virus in
5thweek. Groups 2-4 were injected with 0.5 mL the Bartha-K61,
Hubei
98 and DMEM in 1th, 3th and
5th respectively. At the 32th day
after the final injection, blood samples were collected from 5 mice of
each group for
serum
neutralization assay, and the remaining mice of each group were
challenged with PRV NY isolate. Serum neutralizing antibodies against
PRV were detected as described previously (Zheng et al., 2020).