Zibert A, Thomassen A, Müller L, Nguyen L, Glouchkova L, Fraefel C, Roskrow M, Meisel R, Dilloo D
Clinic for Pediatric-Oncology, -Hematology and -Immunology, University Clinic of Düsseldorf, Germany.
Gene Ther. 2005 Dec;12(23):1707-17. doi: 10.1038/sj.gt.3302577.
For leukemia vaccine generation, high-efficiency gene transfer is required to express immunomodulatory molecules that stimulate potent antileukemic immune responses. In this context, herpes simplex virus type-1 (HSV-1)-derived vectors have proven to be a promising tool for genetic modification of lymphoblastic leukemia cells. Yet, vector-associated viral protein expression might inadvertently modulate vaccine efficacy facilitating both immune evasion and immune stimulation. To explore the issue of immune-stimulation versus immune-suppression in immature lymphoblastic leukemia cells, two types of HSV-1 amplicon vectors, helper virus-dependent and helper virus-free that express the immunomodulatory molecules CD70 and IL-2, were compared with regard to their vector-associated immunomodulatory potential. We first established that lymphoblastic cell lines and primary acute lymphoblastic leukemia (ALL) cells express HSV receptor genes. Lymphoblastic cell lines were transduced with high efficiency, and in primary ALL cells high gene transfer rates of 47+/-15 and 42+/-14% were obtained with helper virus-dependent and -free HSV-1 amplicon vectors, respectively. The efficacy of the two amplicon vectors to induce antineoplastic responses was assessed in a vaccine setting in mice with pre-existing highly malignant lymphoblastic disease. Treatment of mice with vaccine cells transgenically expressing CD70+IL2 significantly suppressed lymphoblastic cell proliferation and improved survival. Of note, when helper virus-dependent HSV-1 amplicon vectors were used for vaccine preparation, the high immunogenic potential of the vector itself, in the absence of transgenic CD70+IL2 expression, seemed to be sufficient to mediate protection comparable to the antineoplastic response achieved by expression of immunomodulatory molecules. Thus for vaccine generation in B lymphoblastic leukemia, the immunogenic potential of HSV-1 helper virus-dependent amplicon vectors does provide additional benefit to the high transduction efficiency of HSV-1-derived vectors.
对于白血病疫苗的制备，需要高效的基因转移来表达免疫调节分子，以刺激强大的抗白血病免疫反应。在这种情况下，1型单纯疱疹病毒（HSV-1）衍生的载体已被证明是用于淋巴细胞白血病细胞基因改造的一种有前景的工具。然而，载体相关的病毒蛋白表达可能会无意中调节疫苗效力，既促进免疫逃逸又刺激免疫反应。为了探究未成熟淋巴细胞白血病细胞中免疫刺激与免疫抑制的问题，比较了两种表达免疫调节分子CD70和IL-2的HSV-1扩增载体，即依赖辅助病毒型和无辅助病毒型，在载体相关免疫调节潜力方面的差异。我们首先确定淋巴细胞系和原发性急性淋巴细胞白血病（ALL）细胞表达HSV受体基因。淋巴细胞系能够高效转导，在原发性ALL细胞中，依赖辅助病毒型和无辅助病毒型HSV-1扩增载体分别获得了47±15%和42±14%的高基因转移率。在患有高度恶性淋巴细胞疾病的小鼠疫苗接种实验中，评估了这两种扩增载体诱导抗肿瘤反应的效力。用转基因表达CD70+IL2的疫苗细胞治疗小鼠，显著抑制了淋巴细胞增殖并提高了生存率。值得注意的是，当使用依赖辅助病毒型HSV-1扩增载体进行疫苗制备时，在没有转基因CD70+IL2表达的情况下，载体本身的高免疫原性潜力似乎足以介导与免疫调节分子表达所实现的抗肿瘤反应相当的保护作用。因此，对于B淋巴细胞白血病疫苗的制备，HSV-1依赖辅助病毒型扩增载体的免疫原性潜力确实为HSV-1衍生载体的高转导效率提供了额外的益处。
