Uchijima M, Yoshida A, Nagata T, Koide Y
Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Japan.
J Immunol. 1998 Nov 15;161(10):5594-9.
In an attempt to study codon usage effects of DNA vaccines on the induction of MHC class I-restricted T cell responses against an intracellular bacterium, Listeria monocytogenes, we designed two plasmid DNA vaccines encoding an H-2Kd-restricted epitope of listeriolysin O (LLO) of L. monocytogenes, LLO 91-99. One DNA vaccine, p91wt, carries the wild-type DNA sequence encoding LLO 91-99, and the other one, p91mam, possesses the altered DNA sequence in which the codon usage was optimized for murine system. Our read-through analyses with LLO 91-99/luciferase fusion genes confirmed that the optimized 91mam DNA sequence showed extremely higher translation efficiency than the wild-type sequence in murine cells. Consistent with this, i.m. injections of p91mam, but not of p91wt, into BALB/c mice were capable of inducing specific CTL- and IFN-gamma-producing CD8+ T cells able to confer partial protection against listerial challenge. Taken together, these observations suggest that optimization of codon should be taken into consideration in the construction of DNA vaccines against nonviral pathogens.
为了研究DNA疫苗的密码子使用对诱导针对细胞内细菌——单核细胞增生李斯特菌的MHC I类限制性T细胞反应的影响，我们设计了两种质粒DNA疫苗，它们编码单核细胞增生李斯特菌溶血素O（LLO）的H-2Kd限制性表位LLO 91-99。一种DNA疫苗p91wt携带编码LLO 91-99的野生型DNA序列，另一种p91mam具有经过优化的DNA序列，其密码子使用情况针对鼠类系统进行了优化。我们对LLO 91-99/荧光素酶融合基因的通读分析证实，在鼠类细胞中，优化后的91mam DNA序列显示出比野生型序列极高的翻译效率。与此一致的是，向BALB/c小鼠肌肉注射p91mam而非p91wt，能够诱导产生特异性CTL和分泌IFN-γ的CD8+ T细胞，这些细胞能够对李斯特菌攻击提供部分保护。综上所述，这些观察结果表明，在构建针对非病毒病原体的DNA疫苗时应考虑密码子的优化。
