Oncolytic viruses have emerged as a promising modality for cancer treatment due to their unique abilities to directly destroy tumor cells and modulate the tumor microenvironment. Bispecific T-cell engagers (BsAbs) have been developed to activate and redirect cytotoxic T lymphocytes, enhancing the antitumor response. To take advantage of the specific infection capacity and carrying ability of exogenous genes, we generated a recombinant herpes simplex virus type 1 (HSV-1), HSV-1-B7H3nb/CD3 or HSV-1-B7H3nb/mCD3, carrying a B7H3nb/CD3 or B7H3nb/mCD3 BsAb that replicates and expresses BsAb in tumor cells in vitro and in vivo. The new generation of oncolytic viruses has been genetically modified using CRISPR/Cas9 technology and the cre-loxp system to increase the efficiency of HSV genome editing. Additionally, we used two fully immunocompetent models (GL261 and MC38) to assess the antitumor effect of HSV-1-B7H3nb/mCD3. Compared with the HSV-1 control virus, HSV-1-B7H3nb/mCD3 induced enhanced anti-tumor immune responses and T-cell infiltration in both GL261 and MC38 models, resulting in improved treatment efficacy in the latter. Furthermore, flow cytometry analysis of the tumor microenvironment confirmed an increase in NK cells and effector CD8 T cells, and a decrease in immunosuppressive cells, including FOXP3+ regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and CD206+ macrophages (M2). Overall, our study identified a novel camel B7H3 nanobody and described the genetic modification of the HSV-1 genome using CRISPR/Cas9 technology and the cre-loxp system. Our findings indicate that expressing B7H3nb/CD3 BsAb could improve the antitumor effects of HSV-1 based oncolytic virus.

中文翻译：

---

表达新型 B7H3nb/CD3 BsAb 的溶瘤 HSV-1 引起的抗肿瘤作用得到改善

溶瘤病毒因其直接破坏肿瘤细胞和调节肿瘤微环境的独特能力而成为一种有前途的癌症治疗方式。双特异性 T 细胞接合剂 (BsAb) 已被开发用于激活和重定向细胞毒性 T 淋巴细胞，从而增强抗肿瘤反应。为了利用外源基因的特异性感染能力和携带能力，我们制备了重组单纯疱疹病毒1型（HSV-1）HSV-1-B7H3nb/CD3或HSV-1-B7H3nb/mCD3，携带B7H3nb/ CD3 或 B7H3nb/mCD3 BsAb 在体外和体内的肿瘤细胞中复制和表达 BsAb。新一代溶瘤病毒采用CRISPR/Cas9技术和cre-loxp系统进行基因改造，提高HSV基因组编辑效率。此外，我们使用两个完全免疫功能的模型（GL261和MC38）来评估HSV-1-B7H3nb/mCD3的抗肿瘤作用。与HSV-1对照病毒相比，HSV-1-B7H3nb/mCD3在GL261和MC38模型中诱导增强的抗肿瘤免疫反应和T细胞浸润，从而提高了后者的治疗效果。此外，肿瘤微环境的流式细胞术分析证实 NK 细胞和效应 CD8 T 细胞增加，免疫抑制细胞减少，包括 FOXP3+ 调节性 T 细胞 (Treg)、骨髓源性抑制细胞 (MDSC) 和 CD206+ 巨噬细胞。 M2）。总体而言，我们的研究鉴定了一种新型骆驼 B7H3 纳米抗体，并描述了使用 CRISPR/Cas9 技术和 cre-loxp 系统对 HSV-1 基因组进行的遗传修饰。我们的研究结果表明，表达 B7H3nb/CD3 BsAb 可以提高基于 HSV-1 的溶瘤病毒的抗肿瘤效果。