Sanchez Violette, Hessler Catherine, DeMonfort Aymeric, Lang Jean, Guy Bruno
Research Department, Sanofi Pasteur, Campus Merieux, 69280 Marcy l'Etoile, France.
FEMS Immunol Med Microbiol. 2006 Feb;46(1):113-23. doi: 10.1111/j.1574-695X.2005.00008.x.
Dengue is an important threat for world-wide public health. Different vaccines are under development, which are currently assessed using a battery of in vitro and in vivo assays before moving on to humans. It is also important to assess vaccine characteristics on human primary cells; among them, dendritic cells, the most efficient antigen-presenting cells, are the first targets of dengue virus infection. In this study, we used flow cytometry to compare the consequences of such an infection by dengue serotype 2 live-attenuated vaccine (LAV2) or its parental strain DEN2 16681 (DEN2). Optimal conditions of infection have first been defined by a mathematical approach, and flow cytometry allowed studying modifications induced in both infected and noninfected dendritic cell populations after surface and intracellular labeling. Both DEN2 and LAV2 increased the expression of the phenotypic markers CD80, CD86, CD40, CD1a, HLA ABC and CD83, demonstrating cellular activation. Stimulated dendritic cells produced tumor necrosis factor-alpha in particular, and, to a lower extent, interleukin 6. Of importance, whereas DEN2 induced cytokine production both in the infected and noninfected populations, LAV2-induced cytokine production was restricted to the infected population. This limited activation triggered by LAV2 would be in agreement with its attenuation. In conclusion, these in vitro experiments using primary human dendritic cells may participate, in combination with other assays, to the evaluation of the immunogenicity and safety of dengue vaccine candidates.
登革热是对全球公共卫生的一项重大威胁。多种疫苗正在研发中，目前在进入人体试验之前，需通过一系列体外和体内试验进行评估。评估疫苗在人原代细胞上的特性也很重要；其中，树突状细胞作为最有效的抗原呈递细胞，是登革热病毒感染的首要靶标。在本研究中，我们使用流式细胞术比较了2型登革热减毒活疫苗（LAV2）或其亲代毒株DEN2 16681（DEN2）感染的后果。首先通过数学方法确定了最佳感染条件，流式细胞术可用于研究表面和细胞内标记后感染和未感染树突状细胞群体中诱导的变化。DEN2和LAV2均增加了表型标志物CD80、CD86、CD40、CD1a、HLA ABC和CD83的表达，表明细胞被激活。受刺激的树突状细胞尤其会产生肿瘤坏死因子-α，以及少量的白细胞介素6。重要的是，DEN2在感染和未感染群体中均诱导细胞因子产生，而LAV2诱导的细胞因子产生仅限于感染群体。LAV2引发的这种有限激活与其减毒作用相符。总之，这些使用人原代树突状细胞的体外实验可能与其他试验相结合，有助于评估登革热候选疫苗的免疫原性和安全性。
