人工抗原提呈细胞联合香菇多糖诱导抗肿瘤免疫反应的研究

Combination therapy of lentinan and artificial antigen-presenting cell induces anti-tumor immune responses

目的:探讨以生物材料为载体的多功能人工抗原提呈细胞(aAPCs)与香菇多糖联合应用在小鼠抗肿瘤中的协同效应。方法:用可生物降解的聚乳酸-羟基乙酸共聚物(PLGA)微球作载体,表面负载H-2Kb/TRP2二聚体以及CD28单抗,内部包裹IL-2以及CTLA-4封闭性抗体,制备表面提呈与旁分泌功能相结合的aAPCs。对黑色素皮下瘤鼠进行3次aAPCs与中药免疫调节剂香菇多糖的联合给药,观察肿瘤生长和免疫反应。结果:该aAPCs与香菇多糖的联合应用能明显抑制移植瘤的生长,延长载瘤鼠的中位生存期,并使外周血、脾脏和肿瘤组织局部的T细胞和TRP2180-188表位特异性CTL细胞大量扩增,同时明显增强了治疗鼠体内NK细胞的杀瘤活性,并降低了Treg细胞的频率。与香菇多糖和aAPCs单独给药组相比,aAPCs与香菇多糖联合应用具有明显的协同作用,即中药的非特异性免疫辅助作用能协助和增强aAPCs的特异性主动免疫反应。结论:本研究首次提示了aAPCs与香菇多糖联合应用在抗肿瘤中的潜在价值,为肿瘤提供了新的免疫治疗策略。

Objective: To investigate the synergistic effects of cell-free artificial antigen-presenting cells (aAPCs) combined use with lentinan in the treatment of tumor in mice. Methods: The aAPCs with surface presentation and paracrine delivery were generated using polylactic-co-glycolic acid microparticles (PLGA-MPs) as a biodegradable scaffold. Both IL-2 and anti-CTLA-4 were co-encapsulated into the cell-sized PLGA-MPs to concurrently present a third signal and anti-inhibitory signal on T cells by paracrine delivery, while H-2K b /TRP2-Ig dimer and anti-CD28 were co-coupled on the surface acted as the first and second signals. The aAPCs were injected into melanoma-bearing mice along with lentinan, a chinese medicine and classical immune modulator, and followed by observation of tumor growth and evaluation of immune response. Results: Three injections of the aAPCs along with lentinan obviously inhibited the tumor growth in a mouse melanoma model and prolonged the medium survival time of tumor-bearing mice. The combined administration of aAPCs and lentinan markedly expanded the T cells and TRP2 180-188-specific CD8 + T cells in the peripheral blood, spleen and tumor tissue;obviously enhanced the cytotoxicity of NK cells;and effectively decreased the frequency of Treg cells. As compared with the aAPCs injection group and lentinan injection group, the combination therapy of aAPCs and lentinan led to the significant synergistic effects in expanding tumor antigen-specific T cells and inhibiting tumor growth. Conclusion: This study, for the first time, indicates the potential value of combination use of aAPCs and lentinan in the treatment of tumor as a novel strategy.