光动力治疗和冻融对肿瘤细胞抗原释放及树突细胞成熟表型的影响

Effect of tumor antigen released during photodynamic therapy or freezing-thawing on the maturation phenotypes of dendritic ceils

目的探讨光动力疗法（PDT）和冻融导致的肿瘤细胞抗原暴露，对体外树突细胞（DC）成熟表型的影响。方法对体外培养的4T1乳腺癌细胞分别予以PDT和反复冻融，检测4T1细胞的坏死与凋亡，收获上清液并与未成熟DC（imDC）或成熟DC（mDC）共同孵育，采用流式细胞法和激光共聚焦显微镜分析DC免疫表型和形态学特征。结果经两种机制处理的4T1细胞都以坏死为主，但PDT较冻融诱导更高的凋亡率（34．7％±9．6％比16．8％±5．1％，P〈0．05）；与上清液孵育后，PDT组imDC的CD80、CD86与I-A／I—E阳性率分另0为22．4％±4．6％、22．5％±5．6％、24．3％±6．3％，冻融组依次为17．3％±3．3％、18．0％±4．7％、20．7％±3．1％，均高于空白对照组（14．2％±3．0％、13．6％±3．3％、15．5％±2．1％，P〈0．05），且PDT组升高更明显，而mDC的免疫表型变化差异无统计学意义（P〉0．05）。结论与冻融相比较，PDT导致更高的细胞凋亡率，更易诱导imDC表达成熟表型。

Objective To investigate the effects of tumor antigen on the maturation phenotypes of dendritic cells through different treatments of antigenic exposure. Methods The necrosis and apoptosis of 4T1 mammary carcinoma cells were detected after an in vitro treatment of photodynamie therapy （PDT） or freezing-thawing. The supernatant of 4T1 cells was harvested and added into the culture of immature or mature dendritic ceils （DCs）. The immune phenotypes and morphological features of DCs were analyzed by flow cytometry and eonfoea[ laser scanning microscopy respectively. Results Necrosis predominated after these treatments. But the apoptotie ratio was higher in PDT cells than that in freezing-thawing cells （34. 7% ±9. 6% vs 16. 8% ± 5.1% , P 〈 0. 05 ） . After co-culturing with different supernatants, the immature DCs of PDT group showed more significant increases of positive rates of CD80 （22.4%±4. 6% ） , CD86 （22. 5% ±5.6% ） and I-A/I-E （24. 3% ± 6. 3% ） versus the immature DCs of freezing-thawing group （ 17.3% ± 3.3% , 18.0% ±4.7% and 20. 7% ± 3.1% respectively, P 〈 0. 05 ） and control group （14.2% ± 3. 0% ±13. 6% ±3.3%~15.5% ±2. 1%,P 〈0.05）. No difference was found between two groups of mature DCs （P 〉 0. 05 ）. Conclusion As compared with the treatment of freezing-thawing, PDT yields a higher apoptotie ratio of 4T1 cells and an elevated expression of maturation phenotypes in imature DCs.