Ulmer J B, Fu T M, Deck R R, Friedman A, Guan L, DeWitt C, Liu X, Wang S, Liu M A, Donnelly J J, Caulfield M J
Department of Virus and Cell Biology, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
J Virol. 1998 Jul;72(7):5648-53. doi: 10.1128/JVI.72.7.5648-5653.1998.
DNA vaccination is an effective means of eliciting both humoral and cellular immunity, including cytotoxic T lymphocytes (CTL). Using an influenza virus model, we previously demonstrated that injection of DNA encoding influenza virus nucleoprotein (NP) induced major histocompatibility complex class I-restricted CTL and cross-strain protection from lethal virus challenge in mice (J. B. Ulmer et al., Science 259:1745-1749, 1993). In the present study, we have characterized in more detail the cellular immune responses induced by NP DNA, which included robust lymphoproliferation and Th1-type cytokine secretion (high levels of gamma interferon and interleukin-2 [IL-2], with little IL-4 or IL-10) in response to antigen-specific restimulation of splenocytes in vitro. These responses were mediated by CD4+ T cells, as shown by in vitro depletion of T-cell subsets. Taken together, these results indicate that immunization with NP DNA primes both cytolytic CD8+ T cells and cytokine-secreting CD4+ T cells. Further, we demonstrate by adoptive transfer and in vivo depletion of T-cell subsets that both of these types of T cells act as effectors in protective immunity against influenza virus challenge conferred by NP DNA.
DNA疫苗接种是引发体液免疫和细胞免疫（包括细胞毒性T淋巴细胞[CTL]）的有效手段。利用流感病毒模型，我们先前证明，注射编码流感病毒核蛋白（NP）的DNA可诱导主要组织相容性复合体I类限制性CTL，并使小鼠在受到致死性病毒攻击时获得交叉株保护（J. B. 厄尔默等人，《科学》259:1745 - 1749，1993年）。在本研究中，我们更详细地描述了NP DNA诱导的细胞免疫反应，其包括体外对脾细胞进行抗原特异性再刺激时出现的强烈淋巴细胞增殖和Th1型细胞因子分泌（高水平的γ干扰素和白细胞介素-2[IL-2]，而IL-4或IL-10很少）。如体外T细胞亚群去除实验所示，这些反应由CD4 + T细胞介导。综上所述，这些结果表明，用NP DNA免疫可启动溶细胞性CD8 + T细胞和分泌细胞因子的CD4 + T细胞。此外，我们通过过继转移和体内T细胞亚群去除实验证明，这两种类型的T细胞均在NP DNA赋予的针对流感病毒攻击的保护性免疫中充当效应细胞。
