Loirat D, Lemonnier F A, Michel M L
Unité de Recombinaison et Expression Génétique, Institut National de la Santé et de la Recherche Médicale, Unité 163, Institut Pasteur, Paris, France.
J Immunol. 2000 Oct 15;165(8):4748-55. doi: 10.4049/jimmunol.165.8.4748.
CTL together with anti-envelope Abs represent major effectors for viral clearance during hepatitis B virus (HBV) infection. The induction of strong cytotoxic and Ab responses against the envelope proteins after DNA-based immunization has been proposed as a promising therapeutic approach to mediate viral clearance in chronically infected patients. Here, we studied the CTL responses against previously described hepatitis B surface Ag (HBsAg)-HLA-A0201-restricted epitopes after DNA-based immunization in HLA-A0201 transgenic mice. The animal model used was Human Human D(b) (HHD) mice, which are deficient for mouse MHC class I molecules (beta(2)-microglobulin(-/-) D(b-/-)) and transgenic for a chimeric HLA-A*0201/D(b) molecule covalently bound to the human beta(2)-microglobulin (HHD(+/+)). Immunization of these mice with a DNA vector encoding the small and the middle HBV envelope proteins carrying HBsAg induced CTL responses against several epitopes in each animal. This study performed on a large number of animals described dominant epitopes with specific CTL induced in all animals and others with a weaker frequency of recognition. These results confirmed the relevance of the HHD transgenic mouse model in the assessment of vaccine constructs for human use. Moreover, genetic immunization of HLA-A2 transgenic mice generates IFN-gamma-secreting CD8(+) T lymphocytes specific for endogenously processed peptides and with recognition specificities similar to those described during self-limited infection in humans. This suggests that responses induced by DNA immunization could have the same immune potential as those developing during natural HBV infection in human patients.
在乙型肝炎病毒（HBV）感染期间，细胞毒性T淋巴细胞（CTL）与抗包膜抗体共同构成病毒清除的主要效应因子。基于DNA的免疫接种后，诱导针对包膜蛋白的强烈细胞毒性和抗体反应，被认为是介导慢性感染患者病毒清除的一种有前景的治疗方法。在此，我们研究了在HLA-A0201转基因小鼠中进行基于DNA的免疫接种后，针对先前描述的乙型肝炎表面抗原（HBsAg）-HLA-A0201限制性表位的CTL反应。所使用的动物模型是人类-人类D(b)（HHD）小鼠，其缺乏小鼠MHC I类分子（β2-微球蛋白-/- D(b-/-)），并转基因表达与人类β2-微球蛋白共价结合的嵌合HLA-A*0201/D(b)分子（HHD(+/+)）。用编码携带HBsAg的乙肝病毒小和中包膜蛋白的DNA载体免疫这些小鼠，在每只动物中均诱导出针对多个表位的CTL反应。这项对大量动物进行的研究描述了在所有动物中诱导出的具有特异性CTL的显性表位，以及其他识别频率较低的表位。这些结果证实了HHD转基因小鼠模型在评估人用疫苗构建体方面的相关性。此外，HLA-A2转基因小鼠的基因免疫可产生针对内源性加工肽的分泌γ干扰素的CD8+ T淋巴细胞，其识别特异性与人类自限性感染期间所描述的相似。这表明DNA免疫诱导的反应可能具有与人类患者自然HBV感染期间产生的反应相同的免疫潜力。
