猪支原体肺炎活疫苗(168株)肺内免疫机制研究

Immunologic Mechanism of the Attenuated Mycoplasma hyopneumoniae 168 Strain Vaccine by Intrapulmonic Immunization in Piglets

为研究猪支原体肺炎活疫苗(168株)的免疫机制,通过肺内接种免疫5～10日龄仔猪,并于免疫后不同时间点检测血清中IgG抗体效价、全血中淋巴细胞转化效率、呼吸道局部的IFN-γ浓度和特异性SIgA滴度,于免疫后28 d剖杀采集呼吸道上皮组织,通过扫描电镜法与原位杂交检测法观察疫苗株在呼吸道的存留以及对纤毛的影响情况。结果发现,免疫后猪血液中淋巴细胞转化增强1.52～2.01倍,支气管表面IFN-γ浓度和特异性SIgA滴度持续增加,但血清抗体一直未检测到。扫描电镜与原位杂交检测结果发现疫苗株能有效地黏附在支气管纤毛上皮细胞上,但对纤毛的影响较小。由此表明,猪支原体肺炎活疫苗(168株)通过肺内免疫可有效激活全身细胞免疫及呼吸道局部的黏膜免疫与细胞免疫反应,而且还可以通过黏附支气管纤毛上皮细胞产生占位效应而对上皮组织不产生损伤。

In order to investigate the immunologic mechanism of the attenuated Mycoplasma hyopneumoniae 168 strain vaccine,5~10 days old piglets were immunized with M.hyopneumoniae 168 strain vaccine by intrapulmonic route.And the specific IgG antibody in serum,lymphoproliferation,IFN-γ and specific secretory IgA(SIgA) antibody in nasal swabs were detected post-immunization(DPI).The persistence of vaccine strain in respiratory tract and the effect on ciliated epithelial cells were detected by in situ hybridization(ISH) and scanning electron microscope(SEM),respectively.The results showed that IFN-γ and specific SIgA were stimulated on surface of respiratory tract after immunization.And peripheral blood mononuclear cells could also be proliferated about 1.52 fold and 2.01 fold on 14 and 28 DPI,when stimulated by M.hyopneumoniae protein in vitro.However,no serum's systemic IgG antibody against M.hyopneumoniae was detected during the whole immune phage.The vaccine strain could stick to the ciliated epithelial cells and show non-harm for the cells.In conclusion,the attenuated M.hyopneumoniae 168 strain vaccine inoculated by intrapulmonic route could activate the systemic cellular immunity,the local mucosal immunity and IFN-γ secretion in respiratory tract against M.hyopneumoniae infection in piglets.In addition,the vaccine strain was safe to the ciliated epithelial cells and could hamper the infection of the field strain by competitive adhension.