Immunoprotective effect of porcine circovirus type 2d Cap-VLP expressed by insect baculovirus on piglets
Porcine circovirus type 2d(PCV2d)is the dominant PCV2 genotype currently prevalent in swine farms.In order to obtain a virus-like particle(VLP)vaccine targeting the PCV2d genotype to improve the prevention and control of porcine circovirus disease.In this study used the baculovirus expression system to express the PCV2d-Cap protein which can self-assemble into VLP.And then nine 21-day-old healthy piglets were randomly divided into VLP group,Challenge control group,and Blank control group(n=3).400 μg of Cap protein-adjuvant complex(PCV2d-VLP vaccine)was injected intramuscularly in the neck on each piglet in the VLP group,An equal volume of PBS with adjuvant mixture was injected in the challenge group,and the blank group was injected with an equal volume of PBS.A total of two vaccinations were administered at 14 d intervals.At 21 d after the second immunization,pigs in the VLP group and the challenge control group were infected with the PCV2 HBDX-2018 strain(106TCID50/each)through the nasal cavity to evaluate the immunoprotective effect induced by the PCV2d-VLP vaccine.The PCV2d-VLP vaccine was able to induce piglets to produce higher levels of specific IgG antibodies and neutralizing antibodies,causing a significant increase in both IFN-γ levels and the proliferative capacity of peripheral blood lymphocytes.The rate of nasal and rectal excretion and the positive rate of viremia were reduced.The pathological damage of the inguinal lymph nodes and spleen were reduced,and the viral load in tissues also reduced.The above studies demonstrated that the PCV2d-Cap protein expressed by baculoviruses could self-assemble into VLPs,which induced a favorable immunoprotective effect in piglets,and had the potential to be further developed into a PCV2d-VLP vaccine.
NETL
NSTL
万方数据
