Abstract：
CD40 agonist antibodies (αCD40) have shown promising anti-tumor response in both preclinical and early clinical studies. However, its systemic administration is associated with immune- and hepato-toxicities which hampers its clinical usage. In addition, αCD40 showed low tumor retention and induced PD-L1 expression which makes tumor microenvironment (TME) immunosuppressive. To overcome these issues, in this study, we have developed a multifunctional Immunosome where αCD40 is conjugated on the surface and RRX-001, a small molecule immunomodulator was encapsulated inside it. Immunosomes showed higher tumor accumulation till 96 h of administration and displayed sustained release of αCD40 in vivo. Immunosomes significantly delayed tumor growth and showed tumor free survival in mice bearing GL-261 glioblastoma by increasing the population of CD45+CD8+ T cells, CD45+CD20+ B cells, CD45+CD11c+ DCs and F4/80+CD86+ cells in TME. Immunosome significantly reduced the population of T-regulatory cells, M2 macrophage, and MDSCs and lowered the PD-L1 expression. Moreover, Immunosomes significantly enhanced the levels of Th1 cytokines (IFN-γ, IL-6, IL-2) over Th2 cytokines (IL-4 and IL-10) which supported anti-tumor response. Most interestingly, Immunosomes averted the in vivo toxicities associated with free αCD40 by lowering the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), IL-6, IL-1α and reduced the degree of liver damage. In addition, Immunosomes treated long-term surviving mice showed tumor specific immune memory response which prevented tumor growth upon rechallenge. Our results suggested that this novel formulation can be further explored in clinics to improve in vivo anti-tumor efficacy of αCD40 with long-lasting tumor specific immunity while reducing the associated toxicities.
摘要：
CD40激动剂抗体（αCD40）在临床前和早期临床研究中均显示出有希望的抗肿瘤反应。然而,它的全身给药与免疫和肝脏毒性有关，这阻碍了它的临床使用。此外,αCD40显示低肿瘤滞留和诱导的PD-L1表达，使肿瘤微环境（TME）免疫抑制。为了克服这些问题,在这项研究中，我们已经开发了一种多功能的免疫小体,其中αCD40在表面上缀合,而RRX-001,一种小分子免疫调节剂被封装在其内部。免疫体显示更高的肿瘤积累，直到给药96小时，并在体内显示αCD40的持续释放。通过增加CD45+CD8+T细胞的数量，免疫组显着延迟肿瘤生长，并在携带GL-261胶质母细胞瘤的小鼠中显示无瘤存活，CD45+CD20+B细胞，TME中的CD45+CD11c+DCs和F4/80+CD86+细胞。免疫小体显著减少了T调节细胞的数量，M2巨噬细胞，和MDSCs并降低PD-L1表达。此外，免疫组显着增强Th1细胞因子（IFN-γ，IL-6，IL-2）超过Th2细胞因子（IL-4和IL-10），支持抗肿瘤反应。最有趣的是，免疫体通过降低丙氨酸氨基转移酶（ALT）的水平，避免了与游离αCD40相关的体内毒性，天冬氨酸转氨酶（AST），IL-6、IL-1α减轻肝损害程度。此外,免疫体治疗长期存活的小鼠显示出肿瘤特异性免疫记忆应答,其在再攻击时阻止肿瘤生长。我们的结果表明，这种新型制剂可以在临床上进一步探索，以提高αCD40的体内抗肿瘤功效，同时具有持久的肿瘤特异性免疫力，同时降低相关的毒性。
