4-1BBL联合Hsp70-肿瘤抗原肽抑制小鼠黑色素瘤肺转移

背景与目的正调节性共刺激分子表达偏低是肿瘤逃避机体免疫系统攻击的重要原因之一,增加这些分子的表达是促进抗肿瘤免疫的研究热点。小鼠黑色素瘤B16-F1细胞株是弱免疫原性癌细胞株。本研究旨在观察4-1BBL联合Hsp70-抗原肽对小鼠黑色素瘤肺转移的抑制作用,并探讨其机制。方法建立小鼠黑色素瘤肺转移模型,Hsp70-B16抗原肽小鼠皮下免疫,同时从尾静脉注射4-1BBL表达质粒p4-1BBL。于接种后第17天,解剖小鼠取肺组织,解剖显微镜下计数黑色素瘤肺转移结节的数目,并检测小鼠部分免疫学指标及肝、肾功能。结果4-1BBL联合Hsp70-B16抗原肽治疗组小鼠黑色素瘤肺转移结节数降至50±8,明显少于二者单独治疗组的500±80和450±40;联合治疗组小鼠血清IL-2和IFN-γ的分泌水平分别增加了4倍和3倍,与对照组相比均存在显著性差异(P<0.01);单独应用4-1BBL基因或与Hsp70-B16抗原肽联合应用对小鼠肝、肾的功能均无明显影响。结论表达4-1BBL联合应用Hsp70-B16抗原肽主要通过增强外周T淋巴细胞功能活性而有效抑制小鼠黑色素瘤肺转移。

Inhibitory effect of 4-1BBL combined with Hsp70-tumor antigen peptides on pulmonary metastasis of melanoma in mice

BACKGROUND & OBJECTIVE: Low level expression of some co-stimulatory molecules is an important mechanism for tumor to evade the attack of immunity system; up-regulating these molecules can enhance antitumor immune response. Mouse melanoma B16-F1 cell line is low immunogenic. This study was designed to investigate the inhibitory effect of co-stimulatory molecule 4-1BBL combined with hot shock protein 70 (Hsp70)-tumor antigen peptides on pulmonary metastasis of melanoma in mice, and to analyze the possible mechanism. METHODS: After establishment of B16-F1 melanoma pulmonary metastasis model, the mice were divided into combination (4-1BBL plus Hsp70-B16) group, 4-1BBL group, Hsp70-B16-F1 group, empty vector group, and normal saline(NS) group, and relevantly received subcutaneous immunization of Hsp70-B16 peptides complex and simultaneous injection of plasmid p4-1BBL via the tail vein. Seventeen days after inoculation of B16 cells, the mice were killed to count pulmonary metastasis nodes under microscope, and to detect a series of immunologic parameters, liver function, and kidney function. RESULTS: The number of pulmonary metastasis nodes was significantly smaller in combination group than in 4-1BBL group and Hsp70-B16 group (50+/-8 vs. 500+/-80 and 450+/-40, P0.01); the levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in serum were significantly higher in combination group than in NS group (200.31+/-25.36 vs. 56.89+/-16.55, P0.05; 1 870.53+/-204.28 vs. 610.30+/-120.05, P0.01). The liver and kidney functions of mice in each group are normal. CONCLUSION: 4-1BBL in combination with Hsp70-B16 peptides can effectively inhibit melanoma pulmonary metastasis mainly through augmenting the function of peripheral T lymphocytes.