Pertmer T M, Roberts T R, Haynes J R
Auragen, Inc., Middleton, Wisconsin 53562, USA.
J Virol. 1996 Sep;70(9):6119-25. doi: 10.1128/JVI.70.9.6119-6125.1996.
Endpoint immunoglobulin G (IgG) titers and cytotoxic T-lymphocyte (CTL) activities were identical between mice immunized via the intramuscular and epidermal (gene gun) routes with 100 and 1 micrograms, respectively, of an influenza virus nucleoprotein (NP) expression vector. However, examination of the relative levels of two IgG subclasses demonstrated that muscle inoculation resulted in predominantly IgG2a responses, whereas gene gun immunization yielded a preponderance of IgG1 antibodies. Inasmuch as these data suggested that muscle inoculation and gene gun delivery elicited Th1-like and Th2-like responses, respectively, gamma interferon release profiles from antigen-stimulated splenocytes were remarkably similar between these groups. Interleukin-4 (IL-4) production assays, on the other hand, revealed qualitative differences that could be correlated with the divergent IgG subclass data. Waning gamma interferon production in gene gun-immunized animals was countered by a marked increase in IL-4 production following the third immunization, as was the case in control animals immunized with inactivated influenza virus formulated with Freund's adjuvant. In contrast, significant levels of IL-4 production were not observed in the intramuscular DNA inoculation group, despite similar decreases in gamma interferon production with increasing immunizations. These data show that intramuscular inoculation leads to Th1-like responses due to elevated IgG2a levels, production of gamma interferon, CTL activity, and lack of IL-4. However, gene gun responses are more difficult to categorize because of the presence of significant gamma interferon and CTL activity on the one hand and elevated IgG1 antibodies and increasing IL-4 production with successive immunizations on the other. In addition, there was a lack of correlation between IgG isotype ratios and cytokine production in all of the NP DNA-immunized animals, in that IgG subclass ratios remained fixed while cytokine production patterns fluctuated with successive immunizations. These data are consistent with the idea that the types of responses elicited following DNA immunization. are dependent on both the identity of the antigen and the route of DNA administration.
分别用100微克和1微克流感病毒核蛋白（NP）表达载体通过肌肉注射和表皮（基因枪）途径免疫的小鼠，其终点免疫球蛋白G（IgG）滴度和细胞毒性T淋巴细胞（CTL）活性相同。然而，对两种IgG亚类相对水平的检测表明，肌肉接种主要产生IgG2a应答，而基因枪免疫则产生大量的IgG1抗体。由于这些数据表明肌肉接种和基因枪递送分别引发了Th1样和Th2样应答，因此这些组之间抗原刺激的脾细胞释放的γ干扰素谱非常相似。另一方面，白细胞介素-4（IL-4）产生试验揭示了与不同的IgG亚类数据相关的定性差异。基因枪免疫动物中γ干扰素产生的减少被第三次免疫后IL-4产生的显著增加所抵消，用弗氏佐剂配制的灭活流感病毒免疫的对照动物也是如此。相比之下，肌肉内DNA接种组未观察到显著水平的IL-4产生，尽管随着免疫次数的增加γ干扰素产生也有类似的减少。这些数据表明，由于IgG2a水平升高、γ干扰素产生、CTL活性以及缺乏IL-4，肌肉内接种导致Th1样应答。然而，基因枪应答更难分类，因为一方面存在显著的γ干扰素和CTL活性，另一方面随着连续免疫IgG1抗体升高且IL-4产生增加。此外，在所有NP DNA免疫的动物中，IgG同种型比例与细胞因子产生之间缺乏相关性，因为IgG亚类比例保持固定，而细胞因子产生模式随连续免疫而波动。这些数据与DNA免疫后引发的应答类型取决于抗原的特性和DNA给药途径的观点一致。
