Abstract: Abstract: Objective To analyze the miＲ-146b-5p in B19 ( MD susceptible) and B21 ( MD resistance) haplotype variation of the expression of chicken infected with MDV and explore the possible after the MD resistance / susceptibility associated molecular mechanism． Method Through MDV virulent strain Md5 poison attack experiments and previous high-throughput sequencing based differences in the expression of miＲ-146b-5p on the further use of real-time PCＲ technology to detect miＲ-146b-5p in B19 and B21 haplotypes chickens 5dpi，10dpi and 21 dpi bursa of fabricius thymus and spleen tissues ( experimental group) and the corresponding uninfected group ( control group) expression changes． Ｒesult MiＲ-146b-5p was significantly different in experimental group and control group at 5dpi，10dpi and 21dpi． The expression of miＲ-146b-5p in B21 group was much higher than that in control group，and the difference was significant． The expression of miＲ-146b-5p in B19 group was higher than that in control group，but the difference was not significant． Conclusion The expression of miＲ-146b-5p in different immune organs after MD infection may be tissue-specific，and there are some differences between different chicken lines after infection，but the specific mechanism needs further study．

Key words: <p>MicroＲNA, MDV, bursa of fabricius, spleen, thymus</p>

摘要： 摘要: 目的 分析 miＲ-146b-5p 在 B19( MD 易感) 与 B21( MD 抗性) 单倍型鸡感染 MDV 后的表达变化规律，并探讨其可能与 MD 抗性/易感性相关的分子机制。方法 我们在 MDV 超强毒株 Md5 攻毒实验和前期高通量测序分析发现，miＲ-146b-5p 表达量有明显差异，为此进一步利用实时荧光定量 PCＲ 技术，检测 MD 感染 B19 和 B21 单倍型鸡 5dpi、10dpi 和 21dpi，miＲ-146b-5p 在法氏囊、胸腺和脾脏组织中的表达量变化情况。结果 miＲ-146b-5p 在 5dpi、 10dpi 和 21dpi 实验组和对照组的表达量明显不同，miＲ-146b-5p 在 B21 实验组中的表达量要远高于对照组，且差异显著; 而 miＲ-146b-5p 在 B19 实验组中的表达量高于对照组但差异不显著。结论 MD 感染后，在不同免疫器官中 miＲ-146b-5p 的表达量可能存在组织特异性，不同鸡系之间在感染后也存在一定的差异，但具体机制尚需进一步深入研究。

关键词: <p>microＲNA, MDV, 法氏囊, 脾脏, 胸腺</p>