De novo genome assembly depicts the immune genomic characteristics of cattle

Immunogenomic loci remain poorly understood because of their genetic complexity and size. Here, we report the de novo assembly of a cattle genome and provide a detailed annotation of the immunogenomic loci. The assembled genome contains 143 contigs (N50 ~ 74.0 Mb). In contrast to the current reference genome (ARS-UCD1.2), 156 gaps are closed and 467 scaffolds are located in our assembly. Importantly, the immunogenomic regions, including three immunoglobulin (IG) loci, four T-cell receptor (TR) loci, and the major histocompatibility complex (MHC) locus, are seamlessly assembled and precisely annotated. With the characterization of 258 IG genes and 657 TR genes distributed across seven genomic loci, we present a detailed depiction of immune gene diversity in cattle. Moreover, the MHC gene structures are integrally revealed with properly phased haplotypes. Together, our work describes a more complete cattle genome, and provides a comprehensive view of its complex immune-genome.

[Different rapid maxillary expansion methods in the treatment of adult patients with obstructive sleep apnea hypopnea syndrome]

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a common sleep respiratory disorder characterized by upper respiratory collapse during sleep, with a high prevalence and potentially fatal complications. Currently, maxillary transverse deficiency are considered to be an important pathogenic factor of OSAHS. For patients with poor compliance with positive airway pressure therapy, rapid maxillary expansion can increase the volume and ventilation of the upper respiratory tract, which is an alternative treatment. This paper reviewed the current research on surgically assisted rapid palatal expansion, miniscrew assisted rapid palatal expansion, and distraction osteogenesis maxillary expansion in the treatment of adult OSAHS. By comparing the indications, contraindications, complications, efficacy and long-term stability of the three treatment methods, it provided reference for treatment of patients with OSAHS.

[Establishment of a CFTR-based detection method for the second messenger cAMP in the cytoplasm]

Objective: To establish a detection method based on Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) that can sensitively detect the second messenger cyclic AMP (cAMP) in the cytoplasm. Methods: The eukaryotic expression vectors of CFTR and YFP-H148Q / I152L were constructed respectively. FRT cells co-expressing CFTR and YFP-H148Q / I152L were obtained by liposome transfection. The expression of CFTR and YFP-H148Q / I152L in FRT cells was observed by an inverted fluorescence microscopy, and flow cytometry was used to detect the purity of cells; The cell model was identified by the fluorescence quenching kinetics test. The validation of the cell model which could screen CFTR modulators was verified by the fluorescence quenching kinetics experiments. The radioimmunoassay was used to detect the cAMP concentration in cytoplasm after adding CFTR activator. Results: The results of the inverted fluorescence microscope showed that CFTR was expressed in the cell membrane and YFP-H148Q / I152L was expressed in the cytoplasm of FRT cells. The FRT cell model stably co-expressing ANO1 and YFP-H148Q / I152L was successfully constructed. The model could screen CFTR modulators, and the slope of fluorescence change and the concentration of CFTR modulators were in a dose-dependent manner. The slope of the fluorescence could reflect the cAMP concentration in the cytoplasm. The cell model could sensitively detect the intracellular cAMP concentration. Conclusion: The cell model could efficiently and sensitively detect the second messenger cAMP concentration in the cytoplasm, and it provided a simple and efficient method for the study of other targets associated cAMP signal.

[Prevalence investigation of plasma cell leukemia in China: a calculation based on national urban medical insurance in 2016]

目的

分析我国城市人口中浆细胞白血病（PCL）的流行病学特征，并测算2016年PCL患病率。

方法

利用我国23个省2016年1月1日至2016年12月31日的城镇基本医疗保险数据进行测算。利用医疗保险数据中的疾病诊断名称和疾病诊断编码识别PCL患者。按性别、地区和年龄进行亚组分析，并通过敏感性分析考察结果的稳健性。基于我国2010年全国人口普查数据计算按年龄调整的标准化患病率。

结果

2016年我国城市人口中PCL患病率为0.11/10万（95％CI 0.05～0.19），其中男性和女性患病率分别为0.12/10万（95％CI 0.06～0.21），0.10/10万（95％CI 0.04～0.19）。PCL的患病率在70～79岁时达高峰。敏感性分析显示本研究结果具有稳健性。根据我国2010年全国人口普查数据所得的标化患病率为0.12/10万（95％CI 0.11～0.13）。

结论

本研究首次利用全国城镇医疗保险数据测算我国PCL的患病率，为PCL相关研究和政策制定提供依据。

Syngeneic homograft of framework regions enhances the affinity of the mouse anti-human epidermal receptor 2 single-chain antibody e23sFv

e23sFv is a HER2-targeted single-chain variable fragment (scFV) that was characterized as the targeting portion of a HER2-targeted tumour proapoptotic molecule in our previous study. In vitro antibody affinity maturation is a method to enhance antibody affinity either by complementarity-determining region (CDR) mutagenesis or by framework region (FR) engraftment. In the present study, the affinity of e23sFv was enhanced using two strategies. In one approach, site-directed mutations were introduced into the FRs of e23sFv (designated EMEY), and in the other approach e23sFv FRs were substituted with FRs from the most homologous screened antibodies (designated EX1 and EX2). Notably, EX1 derived from the FR engraftment strategy demonstrated a 4-fold higher affinity for HER2 compared with e23sFv and was internalized into HER2-overexpressing cells; however, EMEY and EX2 exhibited reduced affinity for HER2 and decreased internalization potential compared with EX1. The 3D structure of EX1 and the HER2-EX1 complex was acquired using molecular homology modelling and docking and the HER2 epitopes of EX1 and the molecular interaction energy of the EX1-HER2 complex were predicted. In the present study, it was demonstrated that scFv affinity improvement based on sequence alignment was feasible and effective. Moreover, the FR grafting strategy was indicated to be more effective and simple compared with site-directed mutagenesis to improve e23sFv affinity. In conclusion, it was indicated that the affinity-improved candidate EX1 may present a great potential for the diagnosis and treatment of HER2-overexpressing tumours.

[Prevalence investigation of solitary plasmacytoma in China: A calculation based on national urban medical insurance in 2016]

目的

分析我国孤立性浆细胞瘤患者分布特征并测算2016年患病率。

方法

基于2016年1月1日至12月31日我国21个省城镇职工和城镇居民医疗保险数据开展研究。通过疾病诊断名称、疾病诊断编码识别孤立性浆细胞瘤患者。根据性别、地区和年龄进行亚组分析，并进行敏感性分析以考察结果的稳健性。基于我国2010年全国人口普查数据、欧洲2013年标准人口数据、美国2010年人口数据以及澳大利亚2011年人口数据计算按年龄调整的标化患病率。

结果

2016年我国孤立性浆细胞瘤患病率为1.18/10万（95%CI 1.06~1.31），其中男性患病率为1.26/10万（95%CI 1.10~1.43），女性患病率为1.10/10万（95%CI 0.93~1.29）。基于我国2010年全国人口普查数据所得标化患病率为0.85/10万（95%CI 0.82~0.88）。

结论

本研究利用全国城镇医疗保险数据测算我国孤立性浆细胞瘤的患病率，为孤立性浆细胞瘤相关医疗政策制定以及基础研究提供线索。

[Calculation of the prevalence of progressive muscular atrophy among adults in China based on urban medical insurance data from 15 provinces]

OBJECTIVE

To analyze the characteristics of patients with progressive muscular atrophy (PMA) and calculate the prevalence of PMA in China in 2016.

METHODS

A retrospective analysis based on China's urban employee basic medical insurance data and the urban residence basic medical insu-rance data from January 1, 2016 to December 31, 2016 was carried out. Children under 18 years old were excluded. Patients with progressive muscular atrophy were identified by disease names and codes. Subgroup analyses by gender, region and age were carried out to calculate the gender-specific, region-specific and age-specific prevalences. Age-adjusted national prevalence was estimated based on 2010 Chinese census data. Sensitivity analyses were done by only considering the observed cases and by excluding the top 10% provinces regarding the missing rate of diagnostic information, respectively.

RESULTS

A total of 996.09 million person-years were included in this study, with 518.41 million person-years in males and 477.67 million person-years in females. The age and gender distribution of the study population was similar to that of the 2010 Chinese census data, therefore the study population was nationally representative. The prevalence of PMA in China in 2016 was 0.28 per 100 000 person-years (95%CI: 0.24-0.33), with 0.21 per 100 000 person-years (95%CI: 0.16-0.26) and 0.35 per 100 000 person-years (95%CI: 0.28-0.42) for females and males, respectively. Regional disparity existed in the Chinese PMA prevalence, with the lowest prevalence in Southwest region (0.11 per 100 000 person-years, 95%CI: 0.07-0.15) and the highest prevalence in Northwest region (3.47 per 100 000 person-years, 95%CI: 0.80-7.99). Age trend in the PMA prevalence was not obvious, but the prevalence among those aged 70 years and older was relatively higher. The age-adjusted prevalence based on 2010 Chinese census data was 0.29 per 100 000 person-years (95%CI: 0.27-0.31). The national prevalences calculated by only considering the observed cases and by excluding the top 10% provinces regar-ding the missing rate of diagnostic information were 0.17 per 100 000 person-years (95%CI: 0.14-0.20) and 0.24 per 100 000 person-years (95%CI: 0.20-0.28), respectively.

CONCLUSION

This study is to calculate the prevalence of PMA among adults in urban China, which can provide basic statistics for the enactment of PMA related medical policies, and clues for the studies on the mechanisms of PMA.

[A cross-sectional study on current status of rare disease related health information based on WeChat official accounts in China]

Objective: To understand the current status of rare disease related health information release in WeChat official accounts in China. Methods: We used a series of key words containing "rare diseases" and the names of the top 30 rare diseases in hospitalizations in China to search WeChat official accounts. Eligible articles were selected by systematic sampling. All including WeChat official accounts and articles were evaluated to extract the basic information. Results: No relevant WeChat official accounts were found for 14 rare diseases (46.67%). Most of the WeChat official accounts (52.17%) were initiated by patients and patient groups. No significant difference was detected in the total number of articles between the official accounts related with Traditional Chinese Medicine (TCM) and non-TCM related ones, however, the frequency of the monthly information release was significantly higher in TCM related official accounts (P<0.001), while the average reading number of articles was significantly higher in non-TCM related official accounts (P<0.001). Nearly 80% of the WeChat official accounts had navigation menu, and the average reading number of official accounts with menus was larger than those without menus. The top three topics were rare disease diagnosis and treatment knowledge (46.00%), public welfare activity for rare diseases (12.81%) and uncorrelated things (8.65%), while the first three leading topics were cutting-edge information, public welfare activity and patient story, respectively. Conclusions: The scale for rare disease related health information release based on WeChat official accounts in China has been basically formed, but it is still in development stage. Many improvements should be made in their coverage of rare diseases, release frequency, topic and form. It is urgent to establish or recreate some high-quality WeChat official accounts in order to provide precise information and effectively facilitate the prevention and treatment of rare diseases.

[An overview of validation methods based on the medical claims database]

Medical claims database is an important source of data for studying the characteristics, and burden of diseases, to provide a basis for the development of policy on management. The database is usually used to identify patients through International Classification of Diseases and free text-building algorithms, thus it is crucial to validate whether the algorithm is correctly identifing the targeted population. This paper introduces both traditional and emerging validation methods including machine learning, natural language processing and database linkage etc.. We also have tried to present a suitable validation method for the current situation in China, so as to promote the application of big data in medical areas and to provide reference for epidemiology studies, based on medical claims database in this country.

Construction of humanized anti-HER2 single-chain variable fragments (husFvs) and achievement of potent tumor suppression with the reconstituted husFv-Fdt-tBid immunoapoptotin

As HER2 is frequently overexpressed in various malignancies, targeting HER2 is considered an efficient, highly selective antitumor therapy. HER2-targeted immunoconjugates are being developed and result in persistent remission of HER2-overexpressing tumors. However, many of the antibodies used as the targeting moiety are of murine origin and exhibit risk of inducing immunogenicity, limiting their antitumor therapeutic efficacy. Here, we humanized e23sFv, an HER2-targeting murine scFv with excellent affinity and specificity, using a human antibody consensus sequence engraftment strategy. The affinity of the initially humanized e23sFv was then rescued and improved by selective mutagenesis followed by phage-display-based affinity panning of the mutant pool. The resulting humanized e23sFv candidates (husFvs) exhibited up-to-94-fold increased affinity to recombinant HER2. The immunogenicity of e23sFv was dramatically alleviated after humanization, as indicated by the impaired production of cytokines by husFv-stimulated human PBMCs. Two internalizable husFvs with optimal affinity were applied to generate humanized immunoapoptotins by infusion with the translocation domain Fdt and the proapoptotic domain truncated Bid. The husFv-immunoapoptotins demonstrated improved HER2-targeting and tumor-killing capacities in vitro and in vivo compared with the e23sFv-immunoapoptotins and would enable the administration of multiple treatment cycles to patients, resulting in improved antitumor efficacy. Furthermore, the husFvs recognized distinct HER2 epitopes and could thus be used in combination with trastuzumab or pertuzumab to achieve robust synergistic antitumor effects in HER2-positive malignancies.

The extracellular domain of Staphylococcus aureus LtaS binds insulin and induces insulin resistance during infection

Insulin resistance is a risk factor for obesity and diabetes and predisposes individuals to Staphylococcus aureus colonization; however, the contribution of S. aureus to insulin resistance remains unclear. Here, we show that S. aureus infection causes impaired glucose tolerance via secretion of an insulin-binding protein extracellular domain of LtaS, eLtaS, which blocks insulin-mediated glucose uptake. Notably, eLtaS transgenic mice (eLtaS ^trans ) exhibited a metabolic syndrome similar to that observed in patients, including increased food and water consumption, impaired glucose tolerance and decreased hepatic glycogen synthesis. Furthermore, transgenic mice showed significant metabolic differences compared to their wild-type counterparts, particularly for the early insulin resistance marker α-hydroxybutyrate. We subsequently developed a full human monoclonal antibody against eLtaS that blocked the interaction between eLtaS and insulin, which effectively restored glucose tolerance in eLtaS ^trans and S. aureus-challenged mice. Thus, our results reveal a mechanism for S. aureus-induced insulin resistance.

Natural Product Vibsanin A Induces Differentiation of Myeloid Leukemia Cells through PKC Activation

All-trans retinoic acid (ATRA)-based cell differentiation therapy has been successful in treating acute promyelocytic leukemia, a unique subtype of acute myeloid leukemia (AML). However, other subtypes of AML display resistance to ATRA-based treatment. In this study, we screened natural, plant-derived vibsane-type diterpenoids for their ability to induce differentiation of myeloid leukemia cells, discovering that vibsanin A potently induced differentiation of AML cell lines and primary blasts. The differentiation-inducing activity of vibsanin A was mediated through direct interaction with and activation of protein kinase C (PKC). Consistent with these findings, pharmacological blockade of PKC activity suppressed vibsanin A-induced differentiation. Mechanistically, vibsanin A-mediated activation of PKC led to induction of the ERK pathway and decreased c-Myc expression. In mouse xenograft models of AML, vibsanin A administration prolonged host survival and inhibited PKC-mediated inflammatory responses correlated with promotion of skin tumors in mice. Collectively, our results offer a preclinical proof of concept for vibsanin A as a myeloid differentiation-inducing compound, with potential application as an antileukemic agent. Cancer Res; 76(9); 2698-709. ©2016 AACR.

Cloning and functional identification of a novel BCA3 splice

The human breast cancer-associated gene (BCA3) was first discovered in breast and prostate cancer cells lines. In vivo studies have shown that BCA3 is mainly expressed in breast tumor cells and not in normal breast and prostate tissues. To date, 3 splice variants of BCA3 have been reported: a double-absent variant lacking exon 3 and exon 5 (BCA3-1), an exon 3-absent variant (BCA3-2), and full-length BCA3. In this study, we investigated whether a novel BCA3 splice variant exists that lacks only the exon 5-encoding sequence. BCA3 variant splices were subcloned and sequenced using reverse transcription-polymerase chain reaction. The preliminary biological functions of the splices were identified using confocal microscopy and a luciferase assay. The absence of exon 3 and exon 5 influenced the subcellular localization of BCA3 and nuclear factor kappa B (NF-kB)-dependent gene expression. Exon 3 and exon 5 of BCA3 may function together to provide a nuclear localization signal or transport sequence to enter the nucleus, and exon 3 may contain specific sequence(s) or domain(s) that influence the NF-κB signal cascade. The discovery of novel BCA3 splicing indicates a new cancer research area, which may increase the understanding of cancer generation and development.

[Influence of excessive complement activation on pathological process of acute graft versus host disease in mice]

This study was aimed to explore the influence of excessive complement activation on the pathological process of acute graft-versus-host disease (aGVHD) in mice. A murine model with aGVHD was established by injecting cell mixture containing splenocytes and bone marrow cells at 2:1 ratio from donor C57BL/6(H-2K(b)) mice into recipient BALB/c (H-2K(d)) mice within 4-6 hours after 8 Gy (60)Co γ-ray total body irradiation. The mice received syngeneic bone marrow transplantation were used as control group. After transplantation, the mice were monitored daily for body weight and mortality. At day 14, all mice were sacrificed and each liver was freshly dissociated for histological analysis. The hepatic mRNA abundance for complement components C3a and C5a as well as receptors for these two anaphylatoxin were tested by real-time quantitative PCR method. And the levels of C3a and C5a production in liver were detected by ELISA. The deposition of complement C3 in liver was determined by immunofluorescence staining using frozen section. The results indicated that as compared with syngeneic bone-marrow transplantation control group, experimental animals underwent aGVHD characterized by weight loss, depilation, diarrhea and lassitude. Interestingly, the hepatic mRNA expression for complement anaphylatoxin family member C3a and C5a as well as their receptors C3aR and C5aR1 in mice with aGVHD were significantly up-regulated in comparison with control group (p < 0.05). Consistently, the content of C3a and C5a in liver increased markedly in mice with aGVHD (p < 0.01). For animals ongoing aGVHD, complement component C3 depositions were observed in hepatic portal areas, around which massive inflammatory cell infiltration was also observed. It is concluded that in aGVHD animals, excessive complement activation occurs, and the activated complement components participate in pathological process of the aGVHD.

CD3 mAb treatment ameliorated the severity of the cGVHD-induced lupus nephritis in mice by up-regulation of Foxp3+ regulatory T cells in the target tissue: kidney

Teff/Treg imbalance orchestrated the onset and the progression of the lupus nephritis in a DBA/2→B6D2F1 murine model with cGVHD. In this paper, we first used 145-2C11 Ab to treat these human SLE-like diseased animals. The results showed that short-term low-dose anti-CD3 antibody treatment induced a significant remission of established proteinuria, production of autoantibodies, immune complex deposition and renal parenchyma lesions in lupus nephritic mice. Of note, we found a robust up-regulation of Foxp3 mRNA expression in the target tissue: kidney from mice with anti-CD3 antibody treatment compared to those with control IgG treatment. Likewise, an increased renal mRNA abundance for IL-10 was also observed in anti-CD3 antibody treated mice. In contrast, genes associated with inflammation and fibrosis as well as cytokines related to effector T cell responses were down-regulated by anti-CD3 mAb treatment. These findings suggested that short-term low-dose anti-CD3 antibody treatment might induced an IL-10-secreting Foxp3(+) regulatory T cells in this cGVHD target tissue: kidney, that suppressed the activation of effector T cells (Th1, Th2 and Th17), thus ameliorating the severity of the lupus nephritis in mice.

A5, a new small-molecule inhibitor of CD4 D1 obtained from a computer-aided screening method, contributes to the inhibition of CD4+ T-cell function

In this study, the authors apply a computer-based strategy to screen thousands of small-molecule, nonpeptidic organic compounds in the Available Chemicals Directory database and to select a series of potential candidates as ligands of the proposed CD4 D1 surface pocket. Then, several cell-based models are used to determine the actual biological functions of these compounds. A small molecule designated A5 (N-((pyridine-4-yl)methylene)thiophene-2-carbohydrazide) was obtained by a virtual screening followed by 3 cell-based functional assays. The results show that A5 could specifically block the CD4-major histocompatibility complex II binding in a rosetting assay, inhibit the mixed lymphocyte reaction-induced T-cell proliferation in a concentration-dependent manner, and reduce the PMA plus ionomycin-stimulated interleukin-2 secretion from peripheral blood mononuclear cells.

Potent inhibition of the CD4-dependent T cell response by J2, a novel nonpeptide organic ligand of CD4 D1

The interaction between CD4 and major histocompatibility complex (MHC) class II proteins is critical for the activation of CD4+ T cells, which are involved in transplantation reactions and a number of autoimmune diseases. It is known that the CD4 N-terminal immunoglobulin variable region-like domain (D1) is directed toward and reaching into the two membrane-proximal domains of the MHC class II molecule. Thus, compounds targeted to D1 would be expected to function as the inhibitors of the interaction of CD4 and class II MHC molecules. In this study, we used a computer-based design method to screen thousands of non-peptidic compounds in a molecular database and identified a group of compounds as potential ligands of CD4 D1. These small organic compounds were then synthesized and tested by actual biological assays. One of them, named J2, which possessed favorable activity, was obtained. Experimental data showed that J2 could specifically block stable CD4-MHC class II binding and elicit significant inhibition of immune responses in vitro and in vivo. All the results demonstrated the therapeutic potential of this compound as a novel immunosuppressive agent.

A novel neutralizing monoclonal antibody against cell-binding polypeptide of ricin

One strain of neutralizing monoclonal antibody (MAb) against cell-binding polypeptide of ricin, named 3E1, was generated efficiently. The antibody recognized the linearity epitope of RTB located in a toxin structure domain characterized by Western blotting. The safe period of mice for intraperitoneal injection of 100 microg of antibody was 20 min after intraperitoneal injection of 2 microg of Ricin (10 times LD50). The neutralizing MAb we obtained could be developed into an immunotherapeutic agent to counteract the use of ricin as a terrorist or biological warfare weapon. It might be useful, as well, for antibody-based prophylaxis.

Proteomic analysis of interleukin 6-induced differentiation in mouse myeloid leukemia cells

Cytokine-induced differentiation of myeloid leukemia cells has important therapeutic implications, but the mechanism remains to be clarified. M1 cell, a mouse acute myeloid leukemia cell line, which underwent growth inhibition, terminal differentiation and apoptosis in response to IL-6, was selected as an experimental model to study on the molecular mechanisms of myeloid cell differentiation on a proteome-wide scale. Cell differentiation was evaluated by cell morphology and CD11b expression. With two-dimensional (2D) gel analyses, 17 protein spots showed obvious changes in quantity during the process of differentiation were found. With matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF-MS) or/and nano-electrospray ionization MS/MS (ESI-MS/MS) analysis, 15 protein spots were identified. The mRNA levels of these 15 proteins during differentiation were also examined using a semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis. Except two proteins, the mRNA levels demonstrated similar expression patterns to what the proteomic analysis revealed. The identified proteins were known to be involved in different cellular functions, including protein synthesis, transcription, signal transduction, cell cycle control, cell rescue and defense, cellular organization, and metabolism. Notably, seven proteins were not described before to be involved in differentiation. Our data provide novel information for a better understanding of the mechanisms by which terminal differentiation of acute myeloid leukemia cells induced by IL-6.

[Association of interleukin-6 induction and the novel gene LX3]

OBJECTIVE

To analyze the association between the expression of the novel gene LX3 and interleukin-6 (IL-6) induction, and explore a new target gene for action mechanism of IL-6.

METHODS

The total RNA was extracted from U937 cells induced by IL-6 at different concentrations and varied lengths of time. Reverse transcriptional (RT)-PCR and Northern blotting were employed to determine the expression of LX3 and IL-6 induction.

RESULTS

The expression of novel gene LX3 was increased while concentration of IL-6 was improved gradually. High expression was induced by IL-6, which was highest at the concentration was 500 ng/ml and no expression at 0 ng/ml. Time- expression pattern proved that expression of novel gene LX3 of higest at 8 hour after induced by IL-6. Northern blotting confirmed that the expression quantity of LX3 increased in U937 cells induced by IL-6.

CONCLUSION

The quantity of LX3 expression is associated with the dose and duration of IL-6 induction, suggesting that LX3 gene is a novel gene correlated with IL-6 induction.

Structural analysis of the epitopes on erbB2 interacted with inhibitory or non-inhibitory monoclonal antibodies

erbB2 oncogene encodes a growth factor receptor. The overexpression of erbB2 was correlated with more aggressive tumors and a poorer prognosis. Some antibodies directed to this molecule have an antitumor effect in vivo, but some antibodies do not. In an attempt to understand the molecular basis of the anti-erbB2 antibody interaction with erbB2 ectodomain (ECD), we analyzed binding epitopes on erbB2 for inhibitory and non-inhibitory antibodies, Herceptin and HF by computer-guided protein engineering and site-directed mutagenesis. Two different interaction domains were identified by molecular docking, computer graphics and distance geometry method and confirmed through studies on a series of mutants of erbB2 ECD. Non-inhibitory antibody HF only recognized N-terminal portion of erbB2 ECD, but inhibitory antibody Herceptin bound to C-terminal portion of it exclusively. The region interacted with inhibitory antibody Herceptin can be an important target for anticancer therapies.

[Expression and Characterization of Single-chain Fv-Fc Fusion Protein against Human P185(erbB2)]

In order to increase therapeutic effects and decrease immunogenicity of mouse McAb, the single-chain Fv (scFv) created by fusing the light and heavy chain variable region genes of anti-human P185(erbB2) McAb was conjugated to the Fc gene of human IgG1 to construct a scFv-Fc fusion gene. The scFv-Fc fusion gene was cloned into the expression vector pCIDN. The scFv-Fc fusion protein was synthesized as secreted two-chain molecule in CHO cells, and purified by affinity chromatography on recombinant protein A. A special 185 kD P185(erbB2) protein was immunoprecipitated by the scFv-Fc fusion protein. The fluorescence-activated cell sorting (FACS) using SK-BR-3 cells as the target indicated that the fusion protein could bind to the extracellular domain of P185(erbB2). The affinity of the scFv-Fc fusion protein, determined by ELISA, was K=7.5x10(-10) (mol/L)(-1). This work laid basis for further studies on the anti-P185(erbB2) scFv-Fc fusion protein.

A trans-envelope protein complex needed for filamentous phage assembly and export

Assembly and export of filamentous phage requires four non-capsid proteins: the outer membrane protein, pIV; the inner membrane proteins, pI and pXI; and a cytoplasmic host factor, thioredoxin. Chemical cross-linking of intact cells demonstrates a trans-membrane complex containing pI and pIV. Formation of the complex protects pI from proteolytic cleavage by an endogenous protease. This protection also requires pXI, which is identical to the C-terminal portion of pI. This indicates that pXI, which is required for phage assembly in its own right, is also part of the complex. This complex forms in the absence of any other phage proteins or the DNA substrate; hence, it represents the first preinitiation step of phage morphogenesis. On the basis of protease protection data, we propose that the preinitiation complex is converted to an initiation complex by binding phage DNA, thioredoxin and the initiating minor coat protein(s).

HIV-1 gp41 by a common immunological epitope induces increased levels of antibodies against human interferon-beta in HIV-1 positive individuals

Based on our finding that a similar epitope exists between human IFN-beta (aa128-134) and HIV-1 gp41 (aa586-595), we examined 20 sera from healthy and 20 from HIV-1 infected individuals for IFN-beta antibody levels by ELISA. The levels of anti-IFN-beta antibody in sera from HIV-infected individuals were increased by about 160% in comparison with HIV-negative. We affinity-purified anti-gp41 antibodies from sera of HIV-1-infected individuals using rsgp41-sepharose column. One of three antibodies could recognize human IFN-beta in comparison with antibodies from serum of a healthy individual. A mouse antiserum to human IFN-beta recognized rsgp41 (recombinant soluble gp41 Env amino acid 539-684), while the normal mouse serum (pre-immune serum) did not bind to rspg41. These results indicate that a common immunological epitope exists between human IFN-beta and HIV-1 gp41. The sequence-similarity suggests that this common immunological epitope may be located in the region aa128-134 of human IFN-beta and the immunosuppressive domain (aa583-599) of HIV-1 gp41. The increased levels of antibodies against interferon-beta in HIV-1 positive individuals may be explained by a common immunological epitope on human IFN-beta and HIV-1 gp41.

A permeabilized cell system that assembles filamentous bacteriophage

A permeabilized cell system has been developed that is capable of assembling filamentous phage only upon addition of exogenous thioredoxin. The in vitro system exhibits the same component requirements seen in vivo: functional thioredoxin, an intact packaging signal in the substrate DNA, and the assembly protein, pIV. This crude in vitro system is insensitive to inhibitors of protein or DNA synthesis, demonstrating that particle assembly uses components that had accumulated before cell permeabilization. The temporal separation of the synthetic period, during which phage proteins and DNA accumulate, from the assembly period enabled us to examine the energy requirement for assembly. We show here that ATP hydrolysis is required for filamentous phage assembly and that the proton motive force is also important.

Tn7 transposition: target DNA recognition is mediated by multiple Tn7-encoded proteins in a purified in vitro system

We have reconstituted the transposition of the bacterial transposon Tn7 into its specific insertion site attTn7 with four purified Tn7-encoded proteins, TnsA+TnsB+TnsC+TnsD, and ATP. TnsA+TnsB+TnsC form a "core" recombination machine that recognizes the transposon ends and executes DNA breakage and joining; TnsD specifically recognizes attTn7. TnsA+TnsB+TnsC are specifically targeted to attTn7 through the TnsD-dependent interaction of TnsC, a nonspecific DNA-binding protein, with attTn7. Recombination appears to be activated by the assembly of a nucleoprotein complex containing the DNA substrates and Tns proteins. We suggest that TnsC plays a central role in communication between the transposon and the target DNA, particularly in directing insertion away from DNAs already containing a copy of Tn7.

Human toxicosis caused by moldy rice contaminated with fusarium and T-2 toxin

This is the first report on human toxicosis in China caused by moldy rice contaminated with Fusarium and T-2 toxin due to heavy rainfall during rice harvest season. One hundred and sixty-five persons ate the moldy rice and ninety-seven persons fall ill of food poisoning. The incidence was 58.8% and latent period was 10-30 min. The chief symptoms were nausea, dizziness, vomiting, chills, abdominal distension, abdominal pain, thoracic stuffiness and diarrhea. The fungi isolated from the moldy rice were predominantly Fusarium heterosporum (F. heterosporum) and F. graminearum. T-2 toxin was found in these moldy rice and the highest level was 420 ppb. The chief causative agent of intoxication was T-2 toxin.

[Food poisoning caused by mouldy rice contaminated with Fusarium and T-2 toxin]

An epidemic of food poisoning in human beings occurred in Tongxiang County, Zhejiang Province after eating mouldy rice contaminated with Fusarium and toxins. Continuous rainfall took place during the rice harvest season. The number of patients poisoned was 97, the rate of incidence was 58.8%. The incubation period was 10 to 30 minutes. The chief symptoms were nausea, dizziness, vomiting, chills, abdominal distension, abdominal pain and diarrhea. The fungi isolated from the mouldy rice were predominantly Fusarium heterosporum and F. graminearum. T-2 toxin was found in the mouldy rice and the highest content was 420 ppb.

Study on BcII/St14 RFLPs in Chinese for DNA diagnosis for hemophilia A

The BcII polymorphism within DXS52 (St14) was reported. It was composed of 4 allelic fragments, 4.0 kb, 3.3 kb, 3.0 kb and 2.3 kb. The frequency of these fragment were 0.09, 0.12, 0.44 and 0.35 respectively in the Chinese. The polymorphism provided the PIC of 0.66. DNA analysis of families with hemophilia A showed that the confidence of the RFLPs was the same as the TaqI/St14 RFLPs and for carrier detection the former is much better than that of the TaqI/St14 RFLPs.