猪流产嗜性衣原体omp-1基因噬菌体疫苗免疫效果评价

Induction of immune responses against Chlamydophila abortus using bacteriophage-mediated DNA vaccination

本试验对猪流产嗜性衣原体omp-1基因噬菌体DNA疫苗进行了免疫效果评价。将猪流产嗜性衣原体omp-1基因插入λNM1149噬菌体载体构建成DNA疫苗,筛选获得阳性噬斑;使用重组的噬菌体疫苗按250 ng/只分别在第2、16和30天三次免疫Balb/c小鼠,以1B弱毒活疫苗(10μg/只)、噬菌体空载体(250 ng/只)为对照组。免疫后分别以ELISA法测定小鼠抗体以及MTT法检测淋巴细胞刺激指数。结果表明重组λ-MOMP噬菌体疫苗虽然未能在短期内(免疫第29天)激发高水平的抗体(1B组免疫第29天抗体D450=0.347,重组噬菌体组免疫第29天抗体D450=0.19;1B组免疫第43天抗体D450=1.12,重组噬菌体组免疫第43天抗体D450=0.38),但能诱导抗体水平逐渐升高(重组噬菌体组免疫前D450=0.086,免疫第29天抗体D450=0.19,免疫第43天抗体D450=0.38),而且显著性诱导T淋巴细胞的增殖(1B组免疫第29天SI=11.67,重组噬菌体组免疫第29天SI=15.8)。相反弱毒疫苗1B株能激发高水平的抗体,但细胞增殖指数显著低于噬菌体疫苗(1B组免疫第29天细胞增殖指数SI=11.67,重组噬菌体组免疫第29天细胞增殖指数SI=15.8)。试验显示λNM1149噬菌体载体具有潜在增强猪流产嗜性衣原体omp-1基因的免疫效果。

omp- 1 gene coding major outer membrane protein of Chlamydi ophila has been identified as one of the most important protection antigens of Chlamydi ophila and plays an important role in cellular immunization of Chlamydia abortus. NM1149 phage vector, a new vaccine delivery system, is able to carry a large gene fragment and its capsid protein can protect the target gene from degradation. In the current study, Omp-1 gene was constructed into NMl149, and a positive bacteriophages was determined and proliferated. Twenty-seven BALB/c mice were randomly assigned to three groups and inoculated intramuscularly with; 1） 10 g （1.5 × 10^5 pfu） live-attenuated vaccine; 2） 250 ng （5 × 10^11 pfu） phage vaccine based on omp-1 gene, and 3） 250 ng （5 × 10^11 pfu） phage vector. All animals were vaccinated at 14 day intervals on day 2, 16 and 30. Antibody levels against major outer membrane and T-lymphocyte proliferation were detected by ELISA and MTT methods. Results showed that mice administrated the phage vaccine developed higher T lymphocyte proliferation levels while those given the live-attenuated 1B vaccine elicited higher antibody levels and less T lymphocyte proliferation. Immunization with phage vaccines may provide a novel way to improve protection against Chlamydophfla abortus infection in small animals.