Guirakhoo F, Pugachev K, Arroyo J, Miller C, Zhang Z-X, Weltzin R, Georgakopoulos K, Catalan J, Ocran S, Draper K, Monath T P
Acambis Inc., Cambridge, Massachusetts 02139, USA.
Virology. 2002 Jun 20;298(1):146-59. doi: 10.1006/viro.2002.1462.
Chimeric yellow fever (YF)-dengue (DEN) viruses (ChimeriVax-DEN) were reconstructed to correct amino acid substitutions within the envelope genes of original constructs described by Guirakhoo et al. (2001, J. Virol. 75, 7290-7304). Viruses were analyzed and compared to the previous constructs containing mutations in terms of their growth kinetics in Vero cells, neurovirulence in mice, and immunogenicity in monkeys as monovalent or tetravalent formulations. All chimeras grew to high titers [ approximately 7 to 8 log(10), plaque-forming units (PFU)/ml] in Vero cells and were less neurovirulent than YF 17D vaccine in mice. For monkey experiments, the dose of DEN2 chimera was lowered to 3 log(10) PFU in the tetravalent mixture in an effort to reduce its dominant immunogenicity. The magnitude of viremia in ChimeriVax-DEN immunized monkeys was similar to that of YF-VAX, but significantly lower than those induced by wild-type DEN viruses. All monkeys developed high levels of neutralizing antibodies against homologous (chimeras) or heterologous (wild-type DEN viruses isolated from different geographical regions) viruses after a single dose of monovalent or tetravalent vaccine. Administration of a second dose of tetravalent vaccine 2 months later increased titers to both homologous and heterologous viruses. A dose adjustment for dengue 2 chimera resulted in a more balanced response against dengue 1, 2, and 3 viruses, but a somewhat higher response against chimeric dengue 4 virus. This indicates that further formulations for dose adjustments need to be tested in monkeys to identify an optimal formulation for humans.
嵌合黄热病（YF）-登革热（DEN）病毒（嵌合疫苗-登革热）经改造，以纠正Guirakhoo等人（2001年，《病毒学杂志》75卷，7290 - 7304页）所描述的原始构建体包膜基因中的氨基酸替换。对这些病毒进行了分析，并与先前含有突变的构建体在Vero细胞中的生长动力学、对小鼠的神经毒性以及作为单价或四价制剂在猴子中的免疫原性方面进行了比较。所有嵌合体在Vero细胞中都能生长至高滴度[约7至8 log(10)，空斑形成单位（PFU）/毫升]，并且在小鼠中神经毒性比YF 17D疫苗低。在猴子实验中，四价混合物中DEN2嵌合体的剂量降至3 log(10) PFU，以降低其主导免疫原性。嵌合疫苗-登革热免疫的猴子中病毒血症的程度与YF-VAX相似，但显著低于野生型DEN病毒诱导的程度。所有猴子在单次接种单价或四价疫苗后都产生了高水平的针对同源（嵌合体）或异源（从不同地理区域分离的野生型DEN病毒）病毒的中和抗体。2个月后接种第二剂四价疫苗提高了对同源和异源病毒的滴度。对登革热2嵌合体的剂量调整导致对登革热1、2和3病毒的反应更加平衡，但对嵌合登革热4病毒的反应略高。这表明需要在猴子中测试进一步的剂量调整配方，以确定适合人类的最佳配方。
