目的  建立地高辛标记DNA探针杂交法，检测基于Madin-Darby犬肾（Madin-Darby canine kidney，MDCK）细胞生产的流感疫苗中宿主DNA的残留量。方法  提取MDCK细胞基因组DNA，制备地高辛标记探针。对地高辛标记DNA探针杂交法进行特异性、灵敏度及稳定性验证, 并用此法检测3批MDCK细胞流感疫苗中的DNA残留量。结果 MDCK细胞基因组DNA的质量浓度为33 ng/μl，260 nm与280 nm波长处的吸光度比值为1.9。制备的探针与非同源细胞DNA无杂交，最低检测限度为10 pg。探针在－70 ℃放置9个月后，检测灵敏度仍可达到10 pg。经检测，MDCK细胞流感疫苗成品中的DNA残留量＜10 ng。结论  建立的地高辛标记探针杂交法特异性强、灵敏度高、稳定好，并且操作简便，可用于MDCK细胞流感疫苗中DNA残留量的检测。

Objective  To establish digoxigenin-labeled DNA probe hybridization for detection of residual host DNA in influenza vaccine derived from Madin-Darby canine kidney (MDCK) cells. Methods The genomic DNA of MDCK cell was extracted. Digoxigenin-labeled DNA probe was prepared. The specificity, sensitivity and stability of digoxigenin-labeled probe hybridization were verified. The method was then used to detect residual DNA in 3 batches of MDCK cell-based influenza vaccines. Results  The concentration of MDCK cell DNA was 33 ng/μl, and the ratio of absorbance at 260 nm and 280 nm was 1.9. No hybridazation between the labeled DNA probe and heterologous DNAs was observed. The minimal detection limit reached 10 pg. The detection sensitivity remained at 10 pg after the labeled probe was stored at -70 ℃ for 9 months. MDCK cell DNA residues in 3 influenza vaccine batches were <10 ng. Conclusions The developed method is specific, sensitive, stable and easy to operate. It can be used for detection of residual DNA in MDCK cell-based influenza vaccine.