Westermann J, Nguyen-Hoai T, Mollweide A, Richter G, Schmetzer O, Kim H-J, Blankenstein Th, Dörken B, Pezzutto A
Department of Hematology, Oncology and Tumorimmunology, Charité - University Medicine Berlin, Campus Berlin-Buch, Berlin, Germany.
Gene Ther. 2004 Jul;11(13):1048-56. doi: 10.1038/sj.gt.3302261.
Since transfection of dendritic cells (DC) plays a key role in DNA vaccination, in vivo expansion of DC might be a tool to increase vaccine efficacy. We asked whether Fms-like tyrosine kinase-3 ligand (Flt-3L), a growth factor for DC, can be used as an adjuvant for DNA vaccination. Beta-galactosidase (beta-gal) was used as a model antigen in C57BL/6 mice. Mice were immunized i.m. with DNA coding for beta-gal with or without additional injection of Flt-3L. In both cases, antigen-specific CD4+ and CD8+ T cells were detectable after vaccination. Compared with DNA alone, additional administration of Flt-3L led to a significant increase in the antigen-specific proliferative response. However, increased cytotoxicity by T cells was not observed. The cytokines secreted by splenocytes of immunized mice upon in vitro stimulation with antigen had a TH2 profile. Humoral responses against beta-gal preferentially consisted of IgG1 antibodies. Analysis of DC from Flt-3L-treated mice revealed an immature phenotype with low or absent expression levels of CD80, CD86 and CD40. We conclude that Flt-3L does not generally skew immune responses towards a TH1 type. More likely, factors determined by the antigen and/or the vaccination procedure itself are crucial for the resulting type of immune response. Flt-3L - under circumstances such as the one we have investigated - can also lead to suppression of TH1 T cell immunity, possibly by expansion of immature/unactivated DC.
由于树突状细胞（DC）的转染在DNA疫苗接种中起关键作用，DC在体内的扩增可能是提高疫苗效力的一种手段。我们研究了DC生长因子Fms样酪氨酸激酶-3配体（Flt-3L）是否可用作DNA疫苗接种的佐剂。在C57BL/6小鼠中，使用β-半乳糖苷酶（β-gal）作为模型抗原。小鼠通过肌肉注射接种编码β-gal的DNA，同时或不额外注射Flt-3L。在这两种情况下，接种疫苗后均可检测到抗原特异性CD4+和CD8+T细胞。与单独使用DNA相比，额外给予Flt-3L导致抗原特异性增殖反应显著增加。然而，未观察到T细胞的细胞毒性增加。免疫小鼠脾细胞在体外受抗原刺激后分泌的细胞因子具有TH2型特征。针对β-gal的体液反应主要由IgG1抗体组成。对Flt-3L处理小鼠的DC分析显示其为未成熟表型，CD80、CD86和CD40的表达水平较低或缺失。我们得出结论，Flt-3L通常不会使免疫反应偏向TH1型。更有可能的是，由抗原和/或疫苗接种程序本身决定的因素对于最终的免疫反应类型至关重要。在我们所研究的这种情况下，Flt-3L也可能通过扩增未成熟/未活化的DC导致TH1 T细胞免疫受到抑制。
