[Objective] Infectious bursal disease （IBD） is a highly contagious immuno- suppressive disease caused by infectious bursal disease virus （IBDV）. IBDV is ge- netically prone to mutation, which results in challenges to the disease prevention and control. Thus, it is necessary to continuously monitor the prevalence of IBDV. [Method] 36 IBDVs were identified from ten provinces in China from 2009 to 2012. Partial fragments of VP2, including the hypervariable region （HVR）, from new iso- lates were sequenced and analyzed through comparisons with published sequences of IBDV, including 18 strains isolated previously by our lab and 24 reference strains from China and around the world. [Result] Phylogenetic analysis showed a co-exis- tence of IBDV strains belonging to classic, variant, attenuated, and very virulent IB- DV （wlBDV） in China. wlBDVs remain the predominant strains in China and the new subgroup was emerging. Alignment analysis revealed several distinct amino acid mutations that might be involved in virulence or antigenicity variation. [Conclu- sion] The results offered evolutionary clues showing the emerging trend of obvious variations and diversity of IBDV in major poultry-producing regions of China particu- larly in recent years. These findings will contribute to a better understanding of the genetic evolution of IBDV.
为筛选出具有抗炎、抗感染免疫调节活性的益生菌并探究益生菌免疫调节活性的主要成分,本研究分别以10株益生菌Lac.1~Lac.10作为候选菌株,将益生菌的活菌体、灭活菌体、菌体裂解物分别作用于由脂多糖+尼日利亚菌素(LPS+Nigericin)诱导的急性炎症巨噬细胞模型及NF-κB和IRF信号通路报告细胞系J774-DualTM巨噬细胞,经荧光定量PCR检测细胞因子Il-1β和Il-10 mRNA的转录水平,通过检测报告基因SEAP和Lucia荧光素酶的活性分析NF-κB和干扰素调节因子(IRF)信号通路的激活情况。结果显示,在排除发酵液中MRS培养基干扰的情况下,益生菌株Lac.5活菌体能够极显著下调巨噬细胞炎症模型下Il-1β mRNA的转录水平(P<0.0001)、极显著上调Il-10 m RNA的转录水平(P<0.0001),并且能够极显著激活巨噬细胞的NF-κB和IRF信号通路(P<0.0001),进一步将益生菌Lac.5活菌体热灭活和超声破碎后显示,益生菌Lac.5灭活菌体和菌体裂解物的免疫调节活性均显著降低,仅益生菌Lac.5活菌体组分起到抗炎、抗感染的免疫调节活性。综上所述,本研究筛选出一株具有抗炎、抗感染的免疫调节活性的益生菌株Lac.5,并确认了其活菌体为免疫调节组分,对功能益生菌的筛选和新型益生菌治疗制剂的开发具有重要意义。
