Cai H, Yu D H, Hu X D, Li S X, Zhu Y X
National Laboratory of Protein Engineering and Plant Genetic Engineering, Peking University, Beijing, People's Republic of China.
DNA Cell Biol. 2006 Aug;25(8):438-47. doi: 10.1089/dna.2006.25.438.
In this study, we demonstrated that calves vaccinated with a combined DNA vaccine encoding Ag85B, MPT- 64, and MPT-83 antigens from the Mycobacterium tuberculosis for the priming and subsequently boosting with BCG prior to experimental challenge with virulent Mycobacterium bovis (M. bovis) resulted in improved immune responses over immunizing. Vaccination with the combined DNA/BCG induced higher levels of antigen- specific gamma interferon (IFN-gamma) in whole-blood cultures 4 weeks after final vaccination and the level of antigen-specific IFN-gamma in response to Ag85, MPT-64, and MPT-83 were still higher 4 weeks after challenge when compared to the combined DNA group. There was a significant bias toward induction of CD4+ T cells rather than CD8+ T cells responses, and the mean percentage of CD4+ T cells was increased about 2.6-fold in peripheral blood mononuclear cells (PBMC) cultures in DNA prime-BCG boost vaccination when compared to the nonvaccinated group. In addition, DNA prime-BCG boost vaccination resulted in stronger humoral immune responses, and the levels of the specific antibodies to three antigens were increased two- to 32- fold when compared to the combined DNA group. Vaccination with the combined DNA/BCG induced a high level of protection against an intratracheal challenge with virulent M. bovis, based on a significant enhancement of six pathological and microbiological parameters of protection compared to the nonvaccinated group. Finally, the combined DNA/BCG increased the protective efficacy by more than 10-100-fold as measured by reduced CFU counts in the lungs from calves challenged with M. bovis compared to the combined DNA and BCG groups. These results suggest that use of the prime-boost strategy offers better protection against bovine tuberculosis than does the combined DNA vaccines and BCG.
在本研究中，我们证明，用编码结核分枝杆菌Ag85B、MPT-64和MPT-83抗原的联合DNA疫苗对犊牛进行初次免疫，随后在用强毒牛分枝杆菌（M. bovis）进行实验性攻击之前用卡介苗（BCG）进行加强免疫，与单独免疫相比，可改善免疫反应。在最后一次接种后4周，联合DNA/BCG疫苗接种在全血培养物中诱导产生更高水平的抗原特异性γ干扰素（IFN-γ），并且在攻击后4周，与联合DNA组相比，对Ag85、MPT-64和MPT-83产生反应的抗原特异性IFN-γ水平仍然更高。诱导CD + T细胞反应而非CD8 + T细胞反应存在显著偏差，与未接种疫苗组相比，DNA初免-BCG加强免疫接种在外周血单核细胞（PBMC）培养物中CD4 + T细胞的平均百分比增加了约2.6倍。此外，DNA初免-BCG加强免疫接种导致更强的体液免疫反应，与联合DNA组相比，针对三种抗原的特异性抗体水平增加了2至32倍。基于与未接种疫苗组相比六个病理和微生物学保护参数的显著增强，联合DNA/BCG疫苗接种对强毒M. bovis气管内攻击诱导了高水平的保护。最后,与联合DNA组和BCG组相比，联合DNA/BCG通过降低受M. bovis攻击的犊牛肺部的CFU计数，使保护效力提高了10至100倍以上。这些结果表明，与联合DNA疫苗和BCG相比，采用初免-加强策略对牛结核病提供了更好的保护。
