Comparison of the protective effects of killed Burkholderia pseudomallei and CpG oligodeoxynucleotide against live challenge

Melioidosis is a fatal disease caused by Burkholderia pseudomallei. Currently there is no vaccine available. Synthetic oligodeoxynucleotides with unmethylated CpG dinucleotide motifs (CpG ODN) can stimulate vertebrate immune cells and clear certain pathogens that are susceptible to a strong Th1 response. In our previous study, pretreatment with CpG ODN alone or CpG-ODN with cationic liposomes for 2–10 or 30 days before B. pseudomallei infection in mice conferred 80–100% protection. In the present study we investigated the protective effect of CpG-ODN together with heat-killed (HK) or paraformaldehyde-killed B. pseudomallei (PP). HK or PP were used to immunize BALB/c mice twice at 15-day intervals before intra-peritoneal challenge with 5LD50 of B. pseudomallei and observed for 30 days. We found that PP could significantly protect mice (60%) with an increased survival time (24.8 ± 11.63 days) while in the HK and PBS groups, all infected mice died within 6 days. Although either CpG ODN or PP conferred significant protection, giving them in combination did not enhance it further. Serum IFN-γ levels on day-5 (before challenge) of the PP and PP + CpG ODN groups were significantly higher than those of the PBS control group. The results further support the importance of IFN-γ in host protection against B. pseudomallei and suggest further study on paraformaldehyde-killed bacteria as a component of a future B. pseudomallei vaccine.     

Polarized immune responses modulated by layered double hydroxides nanoparticle conjugated with CpG

Modulation of the immune response is an important step in the induction of protective humoral and cellular immunity against pathogens. In this study, we investigated the possibility of using a nanomaterial conjugated with the toll-like receptor (TLR) ligand CpG to modulate the immune response towards the preferred polarity. MgAl-layered double hydroxide (LDH) nanomaterial has a very similar chemical composition to Alum, an FDA approved adjuvant for human vaccination. We used a model antigen, ovalbumin (OVA) to demonstrate that MgAl-LDH had comparable adjuvant activity to Alum, but much weaker inflammation. Conjugation of TLR9 ligand CpG to LDH nanoparticles significantly enhanced the antibody response and promoted a switch from Th2 toward Th1 response, demonstrated by a change in the IgG2a:IgG1 ratio. Moreover, immunization of mice with CpG-OVA-conjugated LDH before challenge with OVA-expressing B16/F10 tumor cells retarded tumor growth. Together, these data indicate that LDH nanomaterial can be used as an immune adjuvant to promote Th1 or Th2 dominant immune responses suitable for vaccination purposes.     

CpG岛甲基化表型及OPCML基因甲基化与肝细胞癌发生的关系

背景与目的：CpG岛甲基化表型（CpG island methylator phenotype,CIMP）涉及到多个基因启动子同时甲基化,具有肿瘤特异性,与多种肿瘤的发生或预后相关。但有关肝癌CPG岛甲基化表型的研究罕见报道。OPCML（opioid-binding protein／cell adhesion molecule—like）基因目前多为针对上皮性卵巢癌的研究．被认为是卵巢癌的候选抑癌基因。本研究旨在探讨CIMP及OPCML基因与肝癌的发生是否有关。方法：运用甲基化特异性PCR方法检测50例肝细胞癌组织及48例癌旁组织中OPCML、p15、SOCS-1、GST-P、RAR．b、p16、p73、p14、MGMT和hMLHl基因的甲基化状况。结果：肝癌组织甲基化率普遍比相应癌旁组织甲基化率高：OPCML（70．0％VS．64．6％）、p15（58．0％VS．50．0％）、SOCS-1（78．0％VS．50．0％）、GST—P（56．0％VS．27．1％）、RAR-b（30．0％vs．6．3％）、p16（26．0％vs．14．6％）、p73（16．0％vs．0％）、p14（36．0％vs．27．1％）、MGMT（16．0％vs．10．4％）和hMLH1（18．O％VS．4．2％）。SOCS-1,GST-p,RAR-b,p16和p73基因甲基化率在肝癌组与癌旁组差异有显著性（P〈0．05）,其它基因两组之间的甲基化率差异无显著性。CIMP阳性组（同时具有≥3个位点甲基化）复发时间较早,1年无瘤生存率为18．2％,而CIMP阴性组（具有〈3个位点甲基化）复发时间较晚,1年无瘤生存率为75．0％（P〈0．05）。结论：肝癌中存在着CpG岛甲基化表型（CIMP）。CIMP可作为肝癌患者预后判断的指标之一：OPCML基因甲基化可能在肝癌的发生中发挥重要的作用。     

龙岩市239株沙门菌毒力基因检测结果分析

目的 了解龙岩市沙门菌毒力基因携带与变迁情况,为沙门菌病的防制提供理论依据。方法 对1991-2017年间收集的分离自人体与食品样本的239株沙门菌进行复核鉴定,并用PCR方法检测invA、sopB、sifA、sscA、sseE、spvB、spvC、spvR、pefA等9个沙门菌毒力基因的片段。结果 龙岩市沙门菌以肠炎沙门菌和鼠伤寒沙门菌为主,占62.3%(149/239),属于SPI1的invA、sopB毒力基因检出率为100%,属于SPI2的sseE、sscA、sifA毒力基因的检出率分别为99.2%、95.0%、85.4%,毒力质粒基因spvC检出率71.1%,pefA、spvB、spvR检出率均为46.4%。并且其携带数量也随着时间的进程而显著增加;肠炎沙门菌质粒毒力基因携带率显著高于鼠伤寒沙门菌。肠炎沙门菌以检出全部9种毒力基因为主,占83.5%(76/91);鼠伤寒沙门菌以invA、sopB、sseE、sscA、sifA阳性,spvB、spvR、pefA阴性结果多见,占77.6%(45/58)。人体与食品样本来源的沙门菌所携带毒力基因数量没有差异。结论 龙岩市沙门菌携带毒力基因数量较多,毒力较强,质粒毒力基因随着时间的进程而累积,人源性与食源性沙门菌交叉污染严重,必须加强人、禽、畜沙门菌病的监测与管理。     

逆行岛状皮瓣静脉回流的实验研究

目的 :建立新西兰大白兔隐动静脉逆行岛状皮瓣实验模型 ,探讨静脉逆向回流的机制。方法 :对 5只新西兰大白兔解剖观察 ,建立隐动静脉逆行岛状皮瓣实验模型 ( 3 .0cm× 3 .0cm ,血管蒂长 3 .0cm )。将 10只兔的两侧后肢随机配对分为 2组 ,进行同体对照 ,每组 10个皮瓣。组 1保留隐动静脉血管鞘的完整 ,即保留静脉回流的“迷路”通道。组 2在手术显微镜下 (× 10 )将 3根血管相互分开 ,各自游离 3cm ,即完全破坏静脉回流的“迷路”通道 ,但不损伤 3根动静脉血管。术中放松止血带后分别在 5、15、3 0和60min测定静脉压力 ,术后 10d测定皮瓣成活率 ,切取血管蒂做切片观察。结果 :放松止血带后 ,两组皮瓣的静脉压力均升高 ,约 15min达到高峰 ,后缓慢下降 ,约在 3 0min达到新的平衡。组 2在 3 0、60min的静脉压力均显著低于组 1(P <1.0 1)。但组 1皮瓣成活率 ( 94.5 % )与组 2 ( 10 0 % )无显著差别 (P >0 .0 5 )。结论 :在逆行岛状皮瓣中 ,瓣膜失活途径”较“迷宫途径”更容易实现静脉血的逆流。     

Rett综合征MECP2基因突变分析

目的 分析我国典型的Rett综合征患儿甲基化CpG结合蛋白－2基因（methyl-CpG-binding protein 2,MECP2）突变。方法 使用PCR扩增、单链构象多态性分析、PCR产物克隆和DNA测序的方法。检测分析了26例Rett综合征患儿、其父母和其中2例患儿的妹妹MECP2基因3个外显子的基因突变。结果 26例Rett综合征患儿中发现14例有9种类型MECP2基因的杂合性突变，突变均位于第3外显子。其中7例有3种错义突变：C473T（T158M)4例,C674G(P225R)1例，C916T（R306C）2例；4例有3种无义突变：C502T（R168X）2例，C763T（R255X）1例，C880T（R294X）1例；2种由于缺失导致的突变：1例为1152del 44bp和1例1158－1167／1171－1186del 26bp；1鲍由于碱基插入导致的移码突变：874insA。1158－1167／1171－1186del 26bp和874insA突变为首次报千，突变均为新生突变。此外，新发现了一种源于你亲的错义变异1141G（P381A）。结论 我国Rett综合征患儿存在MECP2基因突变，典型的Rett综合征MECP2基因突变率大于50％。     

CpG-ODN免疫学功能及其应用研究

近年来研究表明,细菌DNA与人工合成的寡核苷酸含有非甲基化的CpG基序,均能激活机体的免疫系统、诱导和增强天然免疫和获得性免疫反应,尤其显示出有效的T_(h1)型免疫佐剂效应,在某些感染性疾病、过敏性疾病和肿瘤等的防治中具有重要的应用前景。本文就近年来关于CpG-ODN的免疫学效应以及CpG-ODN在疫苗研制中的应用等问题进行综述。     

Total expression of HLA-G and TLR-9 in chronic lymphocytic leukemia patients

Suppressed immune status facilitates immune escape mechanisms that allow chronic lymphocytic leukemia cells to proliferate and expand. The expression of HLA-G could effectively inhibit the immune response. In immune response inhibitory signals follow activation of immune system which might be occur during bacterial or viral infection in CLL patients. In the current study we characterized two components of immune system, inhibitory molecule HLA-G with its receptor – CD85j and Toll-like receptor 9.