猪圆环病毒2型感染对猪瘟弱毒疫苗接种猪免疫应答的影响

摘要

为探索猪圆环病毒2型(PCV2)感染对猪瘟(CSF)弱毒疫苗接种猪免疫应答的影响,将20头28 d断奶仔猪随机分为V-I、I-V、V和C4组,5头·组-1.V-I组在接种CSF弱毒疫苗后2d感染PCV2；I-V组在感染PCV2 后2d接种CSF弱毒疫苗;V组只接种CSF弱毒疫苗；C组为空白对照组.共免疫2次,间隔21 d.免疫后定期检测血清CSFV特异性抗体水平、外周血淋巴细胞(PBLC)增殖活性和PBLC中IFN-γ、IL-2、IL-4和IL-10 mRNA的表达水平.结果显示:在CSF弱毒疫苗免疫前或免疫后感染PCV2,均会导致CSFV抗体水平低下,血清抗体阳转率下降,PBLC增殖活性降低.初次免疫后,V-I与I-V组的PBLC内IFN-γ、IL-2、IL-4和IL-10 mRNA的表达量严重不足,其中V-I组的表达量最低.加强免疫后V-I与I-V组的PBLC内IFN-γ与IL-10的表达失衡,IL-2和IL-4的表达缺乏,其中I-V组的细胞因子表达失衡和缺乏更严重.上述研究表明,CSF弱毒疫苗免疫前或免疫后感染PCV2均会影响机体的体液和细胞免疫应答水平,导致PBLC内细胞因子的表达严重抑制和紊乱.%To study the influence of porcine circovirus type 2 (PCV2) infection on immune response of pig to classical swine fever (CSF) vaccine, twenty 28-day-old healthy weaning piglets were randomly divided into four groups of five (Group V-I, I-V, V and C). The piglets in Group V-I were intramuscularly injected with CSF vaccine two days before being inoculated with PCV2, piglets in Group I-V were infected by PCV2 two days before being injected with CSF vaccine, piglets in Group V were only vaccinated by CSF vaccine and Group C as the blank control without inoculating anything. Piglets were vaccinated twice at an interval of twenty-one days and blood samples were collected periodically so as to detect CSFV-specific serum antibody, lymphocyte proliferation activity and mRNA expression levels of IFN-γ, IL-2 and IL-4 in peripheral blood lymphocyte (PBLC). PCV2 infection, either before or after vaccination, reduced CSFV-specific serum antibody production, seroconversion and lymphocyte proliferation activity. After the primary vaccination, expression of IFN-y, IL-2, IL-4 and IL-10 mRNA decreased seriously in PBLC from piglets in Group V-I and Group I-V, especially in Group V-L Following the secondary vaccination, expressions of IFN-γ and IL-10 mRNA in PBLC from Group V-I and Group 1-V appeared seriously unbalanced and those of IL-2 as well as IL-4 mRNA were deficient, especially in Group I-V. In conclusion, PCV2 infection before or after vaccination with CSF vaccine affected porcine humoral and cellular immunity and led to expression suppression and unbalance of cyto-kines in PBLC.