Evaluation of Immune Protective Effect of Recombinant PRRS Attenuated Vaccine Strain Expressing Porcine GM-CSF Against Homologous HP-PRRSV
To evaluate the immunoregulatory characteristics and protection of the recombinant PRRS virus expressing porcine GM-CSF(rPRRSV-GM-CSF)in animals,fifteen 30-day-old piglets were randomly divided into 4 groups.Four piglets in vaccine control group were injected with 105 TCID50 HuN4-F112 strain,3 piglets in experimental group were injected with 105 TCID50 rPRRSV-GM-CSF strain,and 4 piglets in each of blank group and challenge control group were injected with 2 mL DMEM.At 28 days after immunization,HuN4 strains(105 TCID50)was intramuscularly injected into each piglet in experimental group,vaccine control group and challenge control group.Piglets were observed for 28 days post challenge.The results showed that the rPRRSV-GM-CSF group and HuN4-F112 group were completely protected and all piglets in control group died after challenge.Serum samples were collected from piglets at day 14 post immunization and tested for antibody levels with IDEXX ELISA kit.The antibody level of the rPRRSV-GM-CSF group was significantly higher than that of the HuN4-F112 group(P＜0.05)and remained high until the later stage post challenge.Blood samples were also tested in flow cytometry for analysis of the proportion of immune cell subsets.As compared with the HuN4-F112 group,the immune memory cell subsets CD4+CD8+T in the rPRRSV-GM-CSF group significantly increased at day 28 post immunization and the antigen-presenting cells also significantly increased post challenge.In this study,the recombinant virus rPRRSV-GM-CSF was proofed to deliver better immune protection than the currently used HuN4-F112 attenuated vaccine strain,laying a foundation for the further research and development of a new vaccine with broad spectrum cross-protection.
Recombinant vaccine rPRRSV-GM-CSFmemory T lymphocytecytotoxic T lymphocyte
国家科技期刊平台
NSTL
万方数据
维普
