CPP-Id-DC疫苗对淋巴瘤荷瘤鼠的免疫治疗作用和对淋巴瘤细胞攻击的免疫保护效应

Antitumor immune responses induced by idiotype-pulsed dendritic cells with cell-penetrating peptide vaccination in vivo

目的了解树突状细胞(DC)疫苗对淋巴瘤荷瘤鼠的免疫治疗作用及疫苗免疫对淋巴瘤细胞攻击的免疫保护效应。方法将小鼠淋巴瘤A20细胞接种BAL B/c小鼠,建立荷瘤鼠模型,分别接种Id-DC和CPP-Id-DC疫苗,观察荷瘤鼠肿瘤大小变化及生存时间。小鼠预先分别接种Id-DC和PP-Id-DC疫苗,然后以A20细胞攻击,观察其成瘤率及生存时间。均注射PBS作为对照。结果接种PBS的荷瘤鼠肿瘤生长快,中位生存时间为33.4 d;接种Id-DC的荷瘤鼠,个别小鼠肿瘤生长减慢,中位生存时间为40.4 d,与PBS对照组相比,差异无统计学意义;而接种CPP-Id-DC的荷瘤鼠肿瘤生长明显减慢,5只小鼠中,1只肿瘤停止生长,1只肿瘤逐渐缩小、消退,90 d内的中位生存时间为70.8 d,明显长于PBS对照组和Id-DC接种组(P<0.01)。以Id-DC预防接种的小鼠予A20细胞攻击后大部分成瘤(4/5),成瘤时间为7～12 d,较PBS对照组略延长,中位生存时间为44.8 d;CPP-Id-DC接种组小鼠60 d内均无肿瘤生长。结论CPP-Id负载的DC疫苗治疗B细胞淋巴瘤优于单纯Id负载的DC疫苗,可以提高抑瘤率和延长荷瘤鼠的生存时间,可在小鼠体内产生对A20淋巴瘤细胞攻击的免疫保护。

Objective To confirm the therapeutic effect of dendritic cell （DC） vaccine on treatment for mice with lymphoma and the protective effect of DC vaccine loaded with different antigens on the tumor-bearing BAL B/c mice. Methods Firstly, a mouse tumor model was set up by s.c. inoculation of 1 × 10^6/mouse A20 tumor cells. Then different DC vaccines were injected, respectively, and the tumor size and survival time were observed. Secondly, the immunized mice with DC vaccines were challenged with A20 tumor cells, and observed whether a new tumor occurred in the mice and the time of survival. Results The tumor of mice immunized with Id-DC vaccines grew slower than the controls （ mean time of survival was 40.4 days vs. 33.4 days）, but statistically not significantly different. The tumor of mice injected with CPP-Id-DC vaccines grew slower than that injected with Id-DC vaccines and controls, and one of 5 mice got CR and the tumor in another one mouse became stable. The median survival time was 70.8 days during a 90- days observation period. The difference was significant （P 〈 0.01 ）. The mice injected with Id-DC vaccines were challenged with A20 tumor cells showed new tumor occurred at 7 - 12 days, and 1 of the 5 mice survived for 60 days. The mice injected with CPP-Id-DC vaccines had no tumor. Conclusion The DC loaded with CPP-Id was better than that loaded with Id alone in treating B cell lymphoma, and It can enhance their antitumor responses and prolong the survival time of the A20 tumor animal models. The vaccine of DC loaded with CPP-Id can protect mice from A20 tumor cell challenge.