二甲基三十六烷基铵及卡介苗多糖核酸佐剂在结核亚单位疫苗加强BCG免疫中的效应研究

目的 探讨二甲基三十六烷基铵(dimo-thylidioctyl ammonium bromide,DDA)和卡介苗多糖核酸(BCC-PSN)佐剂在结核融合蛋白疫苗加强卡介苗(BCG)免疫中的不同免疫辅助效应.方法 选择DDA、BCG-PSN作为融合蛋白AMM(Ag85B-MPT64190-198-Mtb8.4)的佐剂,在BCG初免小鼠后,AMM疫苗加强免疫两次,其中一组联合使用两种佐剂(DDA/BCG-PSN),另一组单独以DDA作为佐剂,同时设立BCG或磷酸缓冲液(PBS)免疫组为对照.应用ELISA及ELISPOT检测免疫小鼠的体液与细胞免疫反应,最后一次加强免疫后第12周,以H37Rv尾静脉攻毒并检测小鼠肺脾组织细菌载量和病理改变,评价不同佐剂疫苗的保护效果.结果 在BCG初免基础上,联合佐剂组(AMM/DDA/BCG-PSN)和单独佐剂组(AMM/DDA)加强免疫两次后,脾脏淋巴细胞经抗原Ag85B和PPD(purified protein derivative)刺激后,皆可产生分泌较BCG组高的IFN-γ.毒力株攻击后菌落形成单位(colony-forming unit,CFU)计数显示,联合佐剂组(AMM/DDA/BCG-PSN)脾脏荷菌量少于PBS组和BCG组(P<0.05);而单独佐剂组(AMM/DDA)肺部荷菌量少于PBS组和BCG组(P<0.05).组织病理分析结果 表明AMM/DDA/BCG-PSN组肺组织病理损伤较轻,而AMM/DDA组病理损伤个体差异较大.结论 DDA是较为理想的结核亚单位疫苗佐剂,能诱导较强的细胞免疫和免疫保护作用;BCG-PSN可能具有免疫调节作用,可以减轻免疫病理损伤.

DDA and BCG polysaccharide nucleic acid improved the immunogenicity and protective efficacy of tuberculosis subunit vaccine against Mycobacterium tuberculosis infection in mice

Objective To investigate the adjuvant effect of dimo-thylidioctyl ammonium bromide (DDA) and/or DDA-BCG polysaccharide nucleic acid( BCG-PSN), which was combined with a Mycobacterium tuberculosis fusion protein AMM ( Ag 8 5 B - MPT64190-198 - Mtb8.4 ) to boost BCG primed immunization. Methods DDA with or without BCG PSN was mixed with the fusion protein AMM to construct the boosting vaccine. Mice were immunized with BCG and then boosted twice with AMM formulated with the adjuvant DDA with or without BCG-PSN. PBS or BCG vaccination without boosting was used as control. The humoral and cell-mediated immune responses were analyzed by ELISA and ELISPOT. Moreover, the protective efficacy of BCG prime-AMM subunit vaccine boosting against Mycobacterium tuberculosis infection was analyzed. Results With in vitro stimulation of Ag85B and PPD( purified protein derivative) antigen, the number of IFN-γ secreting cells from the mice boosted twice by AMM/DDA/BCG-PSN and AMM/DDA were higher than BCG and PBS group (P <0.05). The CFU in lungs of mice boosted with AMM/DDA/BCG-PSN was less than that of PBS group(P <0.05), while the CFU of AMM/DDA-boosted mice was less than that of BCG and PBS group(P < 0.05).However, fewer lesions were seen in lungs of mice immunized with BCG alone or BCG-prime-AMM/DDA/BCG-PSN boosting than the other groups. Conclusion DDA is an idea adjuvant for tuberculosis subunit vaccine;BCG-PSN might play a role in alleviating the immunity-mediated pathology.