Chikkanna-Gowda C P, Sheahan B J, Fleeton M N, Atkins G J
Department of Microbiology, Moyne Institute, Trinity College, Dublin, Ireland.
Gene Ther. 2005 Aug;12(16):1253-63. doi: 10.1038/sj.gt.3302561.
The Semliki Forest virus (SFV) vector is an RNA-based suicide expression vector that has been used experimentally for tumour therapy. Recently, a new enhanced vector pSFV10-E has been developed that expresses foreign genes at levels up to 10 times higher than the original vector. Interleukin-12 (IL-12), an immunomodulatory cytokine, plays a key role in the induction of T-helper1 responses. The two IL-12 gene subunits were cloned from mouse splenocytes and inserted into the pSFV10-E and pSFV10 (non-enhanced) vectors. Both constructs expressed and secreted biologically active murine IL-12. Administration of high titre rSFV10-E-IL12 particles intratumourally to treat implanted K-BALB tumours in BALB/c mice demonstrated complete tumour regression in comparison to control or rSFV10-IL12 treated groups. High titre rSFV10-E-IL12 particles were also effective in the CT26 tumour model. Histological and immunohistochemical studies revealed tumour necrosis in addition to aggressive influx of CD4+ and CD8+ T cells and other immune cells. Furthermore, inhibition of primary tumour growth and lung metastases of a metastatic (4T1) tumour model indicated the potential of high titres of rSFV10-E-IL12 particles as an efficient antitumour therapeutic agent.
Semliki森林病毒（SFV）载体是一种基于RNA的自杀性表达载体，已被用于肿瘤治疗的实验研究。最近，一种新的增强型载体pSFV10-E被开发出来，其表达外源基因的水平比原始载体高出10倍。白细胞介素-12（IL-12）是一种免疫调节细胞因子，在诱导辅助性T1细胞反应中起关键作用。从小鼠脾细胞中克隆出两个IL-12基因亚基，并将其插入pSFV10-E和pSFV10（非增强型）载体中。两种构建体均表达并分泌具有生物活性的小鼠IL-12。向BALB/c小鼠体内瘤内注射高滴度的rSFV10-E-IL12颗粒以治疗植入的K-BALB肿瘤，与对照组或rSFV10-IL12治疗组相比，肿瘤出现了完全消退。高滴度的rSFV10-E-IL12颗粒在CT26肿瘤模型中也有效。组织学和免疫组化研究显示，除了CD4+和CD8+ T细胞及其他免疫细胞大量涌入外，还出现了肿瘤坏死。此外，在转移性（4T1）肿瘤模型中，对原发性肿瘤生长和肺转移的抑制表明高滴度的rSFV10-E-IL12颗粒具有作为高效抗肿瘤治疗剂的潜力。
