感染传染性法氏囊病毒雏鸡新城疫疫苗二次免疫的免疫增强效应

本实验以 IBDV 感染1日龄滨白雏鸡,在感染鸡14和28日龄或14日龄时点眼,滴鼻接种 Lasota 疫苗,测定了其外周血液、泪液、气管液、肠液、胆汁中 IgG,IgM 和 IgA 含量,血清、泪液、气管液 HI 滴度、血液 T 细胞免疫功能和脾脏 B 细胞抗体生成功能、血液 T、B 细胞和淋巴细胞数量以及法氏囊、胸腺、脾脏、盲肠扁桃体、哈德尔腺、丕氏斑、十二指肠、支气管粘膜的浆细胞和酸性α-萘酚酯酶阳性 T 细胞(ANAE~+T)数量的动态变化,结果表明:1.1 日龄感染 IBDV 雏鸡 ND 疫苗二次免疫后,其法氏囊,脾脏、哈德尔腺、支气管粘膜、盲肠扁桃体、丕氏斑、十二指肠粘膜固有层的浆细胞数量、外周血液 B 细胞数量均明显增高,脾脏 B 细胞抗体生成功能明显增强,血清、泪液、气管液中 IgG,IgA,IgM 含量和 HI 滴度、肠液、胆汁的 IgA,IgM,IgG 含量均显著高于感染一次免疫鸡,但明显低于健康对照二次免疫鸡。感染鸡 ND 二免后,法氏囊出现淋巴滤泡增生,脾脏和盲肠扁桃体的淋巴小结数量增多,直径增大。表明感染鸡 ND 二免后,其全身和消化道、呼吸道局部的体液免疫应答水平较感染一次免疫鸡明显增高,呈现免疫增强效应。2.感染鸡 ND 二免后,其免疫器官和消化道,呼吸道局部免疫组织的 ANAE~+T 细胞数量、外周血液 T 细胞数和免疫功能均较感染一免鸡明显升高。但显著低于对照 ND 二免鸡,证明感染鸡 ND 二免后,其全身和消化道、呼吸道局部的细胞免疫应答较感染一免鸡显著增强。3.ND 强毒攻击后,感染二免鸡的免疫保护率明显高于感染一免鸡,低于对照二免鸡,表明 ND 二次免疫对 IBDV 感染鸡的免疫保护力具有明显的加强作用,这与其全身和消化道、呼吸道局部的体液免疫和细胞免疫应答增强密切相关。

IMMUNOENHANCEMENT MECHANISM OF NEWCASTLE DISEASE REVACCINATION OF CHICKENS INFECTED WITH INFECTIOUS BURSAL DISEASE VIRUS

Chickens were experimentally infected with infectious bursal disease virus at one day of age,and then were inoculated ocularnasally with Lasota vaccine at 14,14 and 28days old.The peripheral blood,tear,trachea washings,intestinal fluids,bile,and the Bursa Fabricius, thymus,spleen,cecal tonsil,Peyer's patch,duodenum,Harder gland and bronchus of experi- mental chickens were collected to determine the dynamic changes of IgG,IgM,IgA,titre of hemagglutination inhibition antibody,T and B cells,lymphocytes,the immune function of T cell in blood and the antibody producing function of splenocytes as well as the number of plasmacytes and acid α-naphthyl acetate esterase positive T cell(ANAE~+T),respectively. The results are as follows. After the revaccination of IBDV infected chickens with ND vaccine,there were the sig- nificant increases of the plasmacytes in the Bursa Fabricius,spleen,Harder gland,cecal tonsil, Peyers patch and in the subepithelium of duodenum and primary bronchus,so was the num- ber of T and B cells and lymphocytes in the blood.The antibody producing function of splenocytes was also markedly promoted,compared with that of the once vaccinated infected chickens.The contents of IgA,IgM,IgG and HI titre in the serum,tear,trachea washings were significantly higher than those of once-immunized infected chickens,which were still remarkably lower than those of the control revaccinated chickens.The revaccination of in- fected chickens also induced the proliferation of lymphoid follicles in the Bursa Fabricius,in- crease and enlargement of lymph nodules in the spleen and cecal tonsil.With the second immunization of the infected chickens with Lasota vaccine,in comparison with that of the once-immunized infected chickens,the persistent and significant increases of ANAE~+T cells occurred in the immune organs and local lymphoid tissues of the digestive and respiratory tract,respectively,which markedly lower than that of the control reimmunized chickens,so did the immune function of T cells in the blood of revaccinated infected chickens.These indi- cated that both of the humeral and cellular immune responses of infected chickens to ND vaccine were significantly enhanced in the systemic immune organs and in the local immune tissues of digestive and respiratory tract by the second ND vaccination which produced excel- lent immunoenhancement. With the challenge exposure of experimental chickens to virulent ND virus by muscular administration,the immune protective rate of the reimmunized infected chickens were appar- ently higher than that of the once immunized infected chickens,but far lower than that of the twice immunized control chickens.This demonstrated that the revaccination of the in- fected chicken with ND vaccine can greatly improved the immunity against ND,which was closely correlated with the significant enhancement of cellular and humeral immune responses to virulent NDV in the systemic lymphoid organs and in the local immune tissues of digestive and respiratory tract of the revaccinated infected chickens.