3.6 Protective immunity induced by recombinant PCP antigen
against A. pleuropneumoniae
Mice injected intraperitoneally with A. pleuropneumoniae serotype
7 (APP7) were used as protective models to examine the protective
immunity of PCP antigens produced here.[5,10] As
the 6×His tag has a small molecular weight and is not charged under
physiological conditions, it is speculated that the retention of the
6×His tag will not affect the immunogenicity of recombinant
antigens.[12] As shown in Fig. 6G , Oml1
and ApxII antigen-immunized mice were all well protected against lethal
challenge with APP7, 90% and 80% of the mice were still alive even
168 h after infection, respectively. However, unlike the high protective
effect of Oml7 previously observed in C.
glutamicum ,[12] Oml7 showed a relatively low
protective effect among the three antigens tested. Only 50% of the mice
survived, but the survival rate was still higher than that of the
control (20%). This low protection of Oml7 may be due to the damage of
protein activity during the purification or storage process. In the
challenge experiment with APP7, the good immune protective effect of
Oml1 observed here once again proved the good cross-protection effect of
the subunit vaccine on different serotypes and its great application
prospects for PCP prevention.