Polymorphisms of IL-4, IL-4Rα, and AICDA Genes in Adult Allergic Asthma

The relationship between 3 polymorphisms sites [interleulin-4 (IL-4), IL-4 receptor (IL-4R)α chain and activation-induced cytidine deaminase (AICDA)] and adult allergic asthma in China was studied. By using case-control method, DNA and clinical data were obtained from allergic asthmatic patients and compared with those in the control subjects. The subjects were genotyped for the IL-4 C-589T promoter polymorphism, the IL-4Rα chain Q576R and the AICDA C8408T by poly-merase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The results showed that the IL-4 C-589T was not associated with adult allergic asthma in China. However, the IL-4Rα chain 576R/R and AICDA 8408T/T frequency was significantly increased in allergic asthma group as compared with that in the control group [odd ratio (OR) = 3. 797 and 9. 127, respectively; P<0. 01)] and was correlated with the increased plasma total IgE. These data suggested that the IL-4Rα chain 576R/R and AICDA 8408T/T genotypes confer genetic susceptibility to adult allergic asthma in China.

Expression of AID, P53, and Mlh1 proteins in endoscopically resected differentiated-type early gastric cancer

AIM: To analyze the expression of the tumor-related proteins in differentiated-type early gastric carcinoma (DEGC) samples. METHODS: Tumor specimens were obtained from 102 patients (75 males and 27 females) who had received an endoscopic tumor resection at Tottori University Hospital between 2007 and 2009. Ninety-one cancer samples corresponded to noninvasive or intramucosal carcinoma according to the Vienna classification system, and 11 samples were submucosal invasive carcinomas. All of the EGCs were histologically differentiated carcinomas. All patients were classified as having Helicobacter pylori (H. pylori) infections by endoscopic atrophic changes or by testing seropositive for H. pylori IgG. All of the samples were histopathologically classified as either tubular or papillary adenocarcinoma according to their structure. The immunohistochemical staining was performed in a blinded manner with respect to the clinical information. Two independent observers evaluated protein expression. All data were statistically analyzed then. RESULTS: The rates of aberrant activation-induced cytidine deaminase (AID) expression and P53 overexpression were both 34.3% in DEGCs. The expression of Mlh1 was lost in 18.6% of DEGCs. Aberrant AID expression was not significantly associated with P53 overexpression in DEGCs. However, AID expression was associated with the severity of mononuclear cell activity in the non-cancerous mucosa adjacent to the tumor (P = 0.064). The rate of P53 expression was significantly greater in flat or depressed tumors than in elevated tumors. The frequency of Mlh1 loss was significantly increased in distal tumors, elevated gross-type tumors, papillary histological-type tumors, and tumors with a severe degree of endoscopic atrophic gastritis (P < 0.05). CONCLUSION: Aberrant AID expression, P53 overexpression, and the loss of Mlh1 were all associated with clinicopathological features and gastric mucosal alterations in DEGCs. The aberrant expression of AID protein may partly contribute to the induction of nuclear P53 expression.

活化诱导胞嘧啶核苷脱氨酶基因多态性与儿童哮喘的关系

目的 活化诱导胞嘧啶核苷脱氨酶 (activation inducedcytidinedeaminase ,AICDA)是一种RNA编辑脱氨酶 ,在免疫球蛋白类别转换中起重要作用。本文探讨AICDA基因 840 8C T基因多态性与儿童哮喘及血浆总IgE的关系。方法 采用聚合酶链反应 限制性片段长度多态性分析技术(PCR RFLP)检测AICDA基因多态性。结果 10 2例哮喘患儿AICDA 840 8位T T基因型频率显著高于72例对照组 ( χ2 =10 .31,P <0 .0 1) ,哮喘患者AICDAT T基因型的相对危险度 (RR)为 4.6 ,T等位基因频率也显著高于对照组 ( χ2 =7.736 ,P <0 .0 1) ,5岁以上T T基因型儿童哮喘患者血浆总IgE显著高于C C和C T基因型患者 (P <0 .0 5 )。结论 AICDA 840 8位T T基因型和T等位基因与儿童哮喘发病相关 ;5岁以上儿童哮喘患者T T基因型与高血浆总IgE相关。

模仿自然界——基于基因高频突变的蛋白质人工进化技术

从上世纪50年代发现DNA双螺旋结构以来,科学家积累了大量的有关生物的生理和病理分子机理的知识。人们期望从生物学的基础研究中衍生出高效、环保的生物相关制造产业,为人类服务。为了发展生物制造产业,生物基础元件蛋白质和基因的制造技术必不可少。最近出现了一种基于基因高频突变的蛋白质人工进化技术。这一技术已成功应用于新抗体的产生,以及抗体和荧光蛋白质的改造。这一技术的进一步发展将成为蛋白质改造、乃至新蛋白质制造的重要工具。

A Novel DT40 Antibody Library for the Generation of Monoclonal Antibodies

Early etiological diagnosis is very important for the control of sudden viral infections,and requires antibodies with both high sensitivity and high specificity.Traditional antibody preparation methods have limitations,such as a long and arduous cycle,complicated operation,and high expenses.A chicken lymphoma cell line,DT40,is known to produce IgM-type antibodies and undergo gene conversion and somatic mutation in the variable region of the immunoglobulin gene during culture.Here,the DT40 cell line was developed to produce antibody libraries and prepare antibody rapidly in vitro.Since hypermutation in DT40 cells was regulated by the activation-induced cytidine deaminase(AID)gene,AID expression needs to be controlled to either fix the Ig sequence by stopping mutation or improve affinity by resuming mutation after the antibodies have been selected.In this study,we generated a novel AID-inducible DT40 cell line(DT40-H7),in which the endogenous AID gene was knocked out using the CRISPR/Cas9 genome editing system,and an inducible AID gene,based on the Tet-Off expression system,was stably transfected.AID expression was controlled in DT40-H7 cells in a simple and efficient manner;gene conversion and point mutations were observed only when AID was expressed.Using the antibody library generated from this cell line,we successfully obtained monoclonal antibodies against the NS1 protein of Zika virus.The DT40-H7 cell line represents a useful tool for the selection and evolution of antibodies and may also be a powerful tool for the rapid selection and generation of diagnostic antibodies for emerging infectious diseases.

Affinity maturation of anti-TNF-alpha scFv with somatic hypermutation in non-B cells

Activation-induced cytidine deaminase(AID)is required for the generation of antibody diversity through initiat-ing both somatic hypermutation(SHM)and class switch recombination.A few research groups have success-fully used the feature of AID for generating mutant li-braries in directed evolution of target proteins in B cells in vitro.B cells,cultured in suspension,are not con-venient for transfection and cloning.In this study,we established an AID-based mutant accumulation and sorting system in adherent human cells.Mouse AID gene was first transfected into the human non-small cell lung carcinoma H1299 cells,and a stable cell clone(H1299-AID)was selected.Afterwards,anti-hTNF-αscFv(ATscFv)was transfected into H1299-AID cells and ATscFv was displayed on the surface of H1299-AID cells.By 4-round amplification/flow cytometric sorting for cells with the highest affinities to hTNF-alpha,two ATscFv mutant gene clones were isolated.Compared with the wild type ATscFv,the two mutants were much more efficient in neutralizing cytotoxicity of hTNF-alpha.The results indicate that directed evolution by somatic hypermutation can be carried out in adherent non-B cells,which makes directed evolution in mammalian cells easier and more efficient.