含表皮生长因子受体的外泌体诱导肿瘤特异性调节T细胞

Epidermal growth factor receptor-containing exosomes induce tumor-specific regulatory T cells

目的探讨树突状细胞(DC)能否捕获含表皮生长因子受体(EGFR)外泌体并转化为成熟DC,诱导生成肿瘤特异性调节T细胞,及后者对肿瘤特异性CD8+T细胞的作用。方法提纯NSCLC肿瘤标本中的外泌体并验证其有EGFR成分,通过外泌体诱导DC转化为免疫耐受型,观察后者诱导生成的调节T细胞对肿瘤特异性CD8+T细胞的影响。结果 NSCLC样本中的EGFR阳性率为80%,而对照肺组织仅为2%。与外泌体共培养7 d后,DC呈现IDO表达高于对照组(80.8%±3.2%vs 65.6%±6.4%,P<0.05)。IDO+DC诱导生成调节T细胞亦明显超过对照组(24.1%±5.2%vs 4.2%±2.3%,P<0.01),进而明显抑制肿瘤特异性CD8+T细胞增殖(5.4%±0.2%vs 86.7%±9.3%,P<0.01)。结论肿瘤细胞的EGFR能够通过外泌体形式排出细胞外,EGFR+外泌体能够诱导免疫耐受IDO+DC产生,进而诱导调节T细胞生成,后者对肿瘤特异性CD8+T细胞有强大抑制作用。

Aim Toinvestigatewhetherepidermal growth factor receptor （ EGFR ）-containing exosomes could induce tumor-specific regulatory T cells, and the effects of those T cells on tumor protein-specific CD8＋Tcells.Methods TheexosomeswithEGFRwerepu-rified from NSCLC tumor, which modulated tolerogenic property of DCs. Then the induced TolDCs generated tumor-specific Tregs, with which the tumor protein-specific CD8 ＋ T cells were suppressed. Results 80%exosomeswereEGFRpositivefromLCpatients while less than 2% exosomes were EGFR positive from control lung tissue. After exposed to the exosomes in the culture for 7 days, the IDO＋ DCs proportion was much higher than that in control group （ 80. 8% ± 3. 2% vs 65. 6% ± 6. 4%, P 〈0. 05 ） . The induced Tregs was also higher （ 24. 1% ± 5. 2% vs 4. 2% ± 2. 3%,P〈0. 01 ） , which suppressed the proliferation of CD8＋ T cells（5. 4% ± 0. 2% vs 86. 7% ± 9. 3%, P〈0.01）.Conclusion Thepurifiedexosomesin-duce tolerogenic DCs. Coculture of the tolerogenic DCs and Th0 cells generates the tumor antigen-specific reg-ulatory T cells. The Tregs could suppress the tumor an-tigen specific CD8＋ T cells.