Single chain antibody fragment display systems: a review / 生物工程学报

Single chain antibody fragment (scFv) is a small molecule composed of a variable region of heavy chain (VH) and a variable region of light chain (VL) of an antibody, and these two chains are connected by a flexible short peptide. scFv is the smallest functional fragment with complete antigen-binding activity, which contains both the antibody-recognizing site and the antigen-binding site. Compared with other antibodies, scFv has the advantages of small molecular weight, strong penetration, low immunogenicity, and easy expression. Currently, the most commonly used display systems for scFv mainly include the phage display system, ribosome display system, mRNA display system, yeast cell surface display system and mammalian cell display system. In recent years, with the development of scFv in the field of medicine, biology, and food safety, they have also attracted much attention in the sectors of biosynthesis and applied research. This review summarizes the advances of scFv display systems in recent years in order to facilitate scFv screening and application.

Phage antibody library technology in tumor therapy: a review / 生物工程学报

Tumor is a serious threat to human health. At present, surgical resection, chemoradiotherapy, targeted therapy and immunotherapy are the main therapeutic strategies. Monoclonal antibody has gradually become an indispensable drug type in the clinical treatment of cancer due to its high efficiency and low toxicity. Phage antibody library technology (PALT) is a novel monoclonal antibody preparation technique. The recombinant immunoglobulin variable region of heavy chain (VH)/variable region of light chain (VL) gene is integrated into the phage vector, and the antibody is expressed on the phage surface in the form of fusion protein to obtain a diverse antibody library. Through the process of adsorption-elution-amplification, the antibody library can be screened to obtain the antibody molecule with specific binding antigen as well as its gene sequence. PALT has the advantages of short antibody production cycle, strong plasticity of antibody structure, large antibody yield, high diversity and direct production of humanized antibodies. It has been used in screening tumor markers and preparation of antibody drugs for breast cancer, gastric cancer, lung cancer and liver cancer. This article reviews the recent progress and the application of PALT in tumor therapy.

Level of health data quality and information use, and contributing factors in the Benishangul Gumuze Region, west Ethiopia: using social ecological framework

Background: Creating responsibility for quality healthcare data and utilization are among the basic functions of leadership. While the benefits of data quality and use are well known, the evidence around the role of healthcare information systems leadership and governance in sustaining data demand and use is limited. Therefore, this study aimed to investigate the level and contributing factors of health data quality and information use in Assosa district, Benishangule Gumuze Region. Methods: A mixed approach design, using qualitative exploration and a facility-based quantitative cross-sectional approach was used. Seventeen departments from two health facilities were enrolled for the quantitative component, while 28 in-depth interviews were conducted to complete the qualitative part of the study. A phenomenological approach was used to explore factors influencing the quality and use of health data. Quantitative data was analyzed descriptively using tables and graphs, whereas qualitative data was analyzed using content analysis guided by the framework for the social ecological model. Results: The average levels of information use and report accuracy were 38.6 and 119.33, respectively. Three themes emerged, explaining the main factors that influence quality data generation: individual characteristics, facility and environmental factors, and leadership and governance characteristics. Individual characteristics were motivation, capacity building, commitment, and digital literacy, while facility and environmental factors included infrastructure, healthcare information system resources and supportive supervision. Furthermore, among the leadership and governance related factors, healthcare data, assigning the right person, and system regulation were some of the factors which were identified. Conclusions: The level of health data quality and its utilization was low during the Asossa city adminstration. The unfriendly physical and organizational working environments and high staff turnover which negatively affected the leadership and governance of the health system are some of the reasons which were sighted with regards to the poor quality of data and information use. Therefore, interventions that have multifaceted effects on data quality and use, such as improving leadership and governance practices and behavior should be implemented. [Ethiop. J. Health Dev. 2022;36 (SI-1)]

The Versatility of Framework Regions of Chicken V(H) and V(L) to Mutations

To identify the interchangeability of V(H) and V(L) framework region (FR) residues, we artificially introduced random mutations at all residue positions in a chicken monoclonal antibody, which has only one functional V(H) and Vλ gene. When we classified the amino acids into 5 groups by their physicochemical properties, all FR residues could be replaced by another group except L23 (C), H36 (W), H86 (D), H104 (G), and H106 (G). Eighty-two (50.9%), 48 (29.8%), 17 (10.6%), and 9 FR residues (5.6%) could be replaced by 4, 3, 2, and 1 group(s), individually, without significant loss of reactivity. We also confirmed a similar level of versatility with 2 different chicken antibodies. This high level of versatility on FR residues has not been predicted because it has not been observed in the 150 chicken antibodies that we previously generated or in the 1,269 naïve chicken V(H) sequences publically available. In conclusion, chicken antibody FR residues are highly interchangeable and this property can be applied for improving the physicochemical property of antibody including thermal stability, solubility and viscosity.

Preparation and identification of anti-human ICAM-1 scFv / 生物工程学报

To screen the specific anti-human intercellular adhesion molecule-1 (ICAM-1) single chain fragment variable (scFv) using phage display library technology and to identify its biological activity. P1 peptide was used as antigen, and the phage antibodies against human ICAM-1 antigen were panned by four binding-eluting-amplifying cycles using Tomlinson I+J phage display library. After four rounds of selective enrichment screening, the positive clones were determined by PCR, enzyme linked immunosorbent assay (ELISA)-based antigenic cross reaction and Dot blotting. Then the binding specificity and biological activity of purified scFv were identified by Western blotting, competitive ELISA and cell adhesion inhibition assay respectively. Furthermore, four positive clones were first panned through P1 peptide coated-ELISA assay, and then J-A1 was obtained and identified by PCR, ELISA-based antigenic cross reaction and Dot blotting, which could show a specific binding between P1 peptide and human ICAM-1 protein antigen. Subsequently, the purified scFv showed a satisfactory specificity and anti-adhesive activity in competitive ELISA and the cell adhesion inhibition assay. The specific anti-human ICAM-1 scFv was prepared successfully from Tomlinson I+J phage display library, which pave the way for further application of anti-human ICAM-1 scFv for inflammation diseases therapeutics.

BRAF V600E and MAP2K1 Mutations in Hairy Cell Leukemia and Splenic Marginal Zone Lymphoma Cases

No abstract available.

Cloning of VH and VL Gene of Human anti-IL1RAP McAb and Construction of Recombinant Chimeric Receptor / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To clone the variable region genes of human anti-IL1RAP (IL-1 receptor accessory protein) monoclonal antibodies (McAb) and to construct IL1RAP chimeric antigen receptors (CARs).</p><p><b>METHODS</b>The VH and VL DNA of IL1RAP single chain antibodies were amplified by RACE and overlap extension PCR from total RNA extracted from 3H6E10 and 10D8A7 hybridoma and ligated into specific IL1RAP single-chain variable fragments (scFv). CD8α transmembrane domain, CD137 intracellular domain, TCR ζ chain, human CD8α signal peptide and scFv-anti-IL1RAP were cloned into plasmid LV-lac. Recombinant lentiviruses were generated by co-transfection of recombinant plasmid LV-lac, pMD2. G, and psPAX2 helper vectors into 293FT packing cells.</p><p><b>RESULTS</b>The VH and VL genes of 2 human anti-IL1RAP McAb were acquired. The 3H6E10 VH and VL genes consisted of 402 bp and 393 bp encoding 134 and 131 aminoacid residues, respectively; 10D8A7 VH and VL genes consisted of 423 bp and 381 bp encoding 141 and 127 amine acid residues, respectively. Recombinant expression vertors LV-3H6E10 scFv-ICD and LV-10D8A7 scFv-ICD (ICD: CD8α transmembrane domain-CD137 intracellular domain-TCR ζ chain) were constructed. The target fragments were demonstrated by sequencing analysis. Recombinant plasmids were transfected into 293FT cells and lentiviral particles were acquired.</p><p><b>CONCLUSION</b>Human anti-IL1RAP recombinant receptors are constructed successfully and lay a good foundation for the construction of IL1RAP-CAR killer T cell vaccine.</p>

Correlation of immunoglobulin variable heavy chain gene mutation status with prognosis in patients with mantle cell lymphoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the relationship between immunoglobulin variable heavy chain (IgVH) gene mutation status and clinical features, pathologic findings and biologic behavior of mantle cell lymphoma (MCL).</p><p><b>METHODS</b>IgVH gene was amplified in 60 cases of MCL with FR1-JH and FR2-JH primers in BIOMED-2. The sequence was determined by cloning. The IgVH somatic mutational status was analyzed using NCBI's Ig-Blast tool. The relationship between IgVH gene mutation status and clinicopathologic features was also analyzed.</p><p><b>RESULTS</b>Forty percent (24 cases, 28 functional Ig genes) of the MCL cases displayed somatically mutated VH genes (defined as > 2% mutated), whereas 60.0% (36 cases, 40 functional Ig genes) showed unmutated VH genes. The most widely used genes were VH3-21 (27.9%) and VH4-34 (19.1%). The former were mainly used by unmutated cases, while the later mainly by mutated cases.Intraclonal heterogeneity was noted in 19 cases. There was no correlation of VH mutation status and specific VH gene with survival (P > 0.05).</p><p><b>CONCLUSIONS</b>MCL comprises at least two subsets that do not correlate with morphology: one with unmutated VH genes and one with mutated VH genes. The biased use of VH3-21 and VH4-34 is noted. The nonrandom usage of IgVH segments suggests specific antigens may play a role in the pathogenesis and progression of MCL subsets. There is no correlation of IgVH mutation status and specific VH gene with survival.</p>

Comprehensiveness and programmatic vulnerability to stds/hiv/aids in primary care / La integralidad y vulnerabilidad programática de las ets/vih/sida en la atención básica / A integralidade e a vulnerabilidade programática às DST/HIV/AIDS na Atenção Básica




This study aimed to identify programmatic vulnerability to STDs/HIV/AIDS in primary health centers (PHCs). This is a descrip - tive and quantitative study carried out in the city of São Paulo. An online survey was applied (FormSUS platform), involving administrators from 442 PHCs in the city, with responses received from 328 of them (74.2%), of which 53.6% were nurses. At - tention was raised in relation to program - matic vulnerability in the PHCs regarding certain items of infrastructure, prevention, treatment, prenatal care and integration among services on STDs/HIV/AIDS care. It was concluded that in order to reach comprehensiveness of actions for HIV/ AIDS in primary health care, it is necessary to consider programmatic vulnerability, in addition to more investment and reor - ganization of services in a dialogue with the stakeholders (users, multidisciplinary teams, and managers, among others).


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Objetivo Fue identificar la vulnerabilidad programática de las Unidades Básicas de Salud con la atención a las ETS/VIH/SIDA. Método Es un estudio descriptivo con un abordaje cuantitativo llevado a cabo en el Municipio de San Pablo. Fue utilizado un formulario online (el FormSUS) con los gerentes de las 442 Unidades Básicas de Salud del Municipio de San Pablo. Participaran en el estudio 74.2% de los gerentes, estos 53.6% eran enfermeros. Resultados Se destaca la vulnerabilidad programática de las Unidades Básicas de Salud en relación a algunos elementos de la infraestructura, acciones de prevención, tratamiento, prenatal y la integración entre los servicios en la atención a las ETS/VIH/SIDA. Conclusión La construcción de tales marcadores constituye un instrumento, presentado en otro artículo, el cual puede ayudar a apoyar la captura de vulnerabilidades de las mujeres en relación a las ETS/VIH en el contexto de los servicios de Atención Primaria de Salud. Los marcadores constituyen importante herramienta para operacionalizar el concepto de vulnerabilidad en la Atención Primaria. Además, promueven procesos de trabajo inter e multidisciplinar e inter e multisectorial. La propuesta de un instrumento basado en dichos marcadores puede apoyar la captura de la vulnerabilidad de las mujeres en relación a las ETS/VIH. .

Objetivo Identificar a vulnerabilidade programática às DST/HIV/aids na Atenção Básica para o enfrentamento do HIV/Aids. Método Estudo descritivo, com abordagem quantitativa, realizado no Município de São Paulo (MSP). Utilizou-se formulário online (FormSUS), com gerentes das 442 Unidades Básicas de Saúde (UBS) do MSP. Participaram do estudo 74,2% gerentes, dos quais 53,6% eram enfermeiros. Resultados Destaca-se a vulnerabilidade programática nas UBS com relação a alguns itens de infraestrutura, ações de prevenção, de tratamento, no pré-natal e de integração entre os serviços na atenção às DST/HIV/aids. Conclusão Para a efetivação da integralidade no enfrentamento do HIV/aids na Atenção Básica é necessário atentar para a vulnerabilidade programática, além de mais investimentos e reorganização dos serviços, num diálogo com os atores sociais envolvidos (usuários, equipe multiprofissional, gerentes, gestores, entre outros).


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Characterization of human αβTCR repertoire and discovery of D-D fusion in TCRβ chains

The characterization of the human T-cell receptor (TCR) repertoire has made remarkable progress, with most of the work focusing on the TCRβ chains. Here, we analyzed the diversity and complexity of both the TCRα and TCRβ repertoires of three healthy donors. We found that the diversity of the TCRα repertoire is higher than that of the TCRβ repertoire, whereas the usages of the V and J genes tended to be preferential with similar TRAV and TRAJ patterns in all three donors. The V-J pairings, like the V and J gene usages, were slightly preferential. We also found that the TRDV1 gene rearranges with the majority of TRAJ genes, suggesting that TRDV1 is a shared TRAV/DV gene (TRAV42/DV1). Moreover, we uncovered the presence of tandem TRBD (TRB D gene) usage in ~2% of the productive human TCRβ CDR3 sequences.

Optimizing the host bacteria to make a large naive phage antibody library in the recombination system / 药学学报

To prepare large naive phage antibody library, the host bacteria with high transformation efficiency is used in the Cre-LoxP recombination system. The variable regions of immunoglobulin light and heavy genes were amplified from lymphocytes collected from adult peripheral blood and newborn cord blood. The genes were spliced to form the single-chain variable fragments (scFv) by overlap PCR, cloned into pDAN5a vector and then transformed into XL2-blue MRF' with the Hte gene. Compared with XL1-blue strain, the size of the primary library was increased by 3.9 times. The primary library infected Cre recombinase-expressing bacteria, and the genes between phagemids created many new VH/VL combinations. The library was calculated to have a diversity of 1.7 x 10(11) and validated by the selection of antibodies against six different protein antigens. This library provides the basis for further selection of antibody-based drugs. It is the first time to report that XL2-blue MRF' can be used to improve the diversity of the library in the recombination system.

Expression, crystallization and crystallographic study of the 1st IgV domain of human CD96 / 生物工程学报

CD96 (Tactile) is an adhesion receptor expressed mainly on activated T cells, NK cells. As a family member of the immunoglobulin-like cell receptor, CD96 consists of three immunoglobulin-like domains (V1, V2/C and C) in the extracellular region. Recent studies have shown that the 1st IgV domain of CD96 (CD96V1) plays an essential role in cell adhesion and NK cell-mediated killing. In this study, the 1st IgV domain of human CD96 (hCD96V1) was cloned and expressed in Escherichia coli (BL21). The soluble protein was obtained by refolding of the hCD96V1 inclusion bodies. From analytical ultracentrifugation, we could predict that CD96 V1 maily exists as dimer with approximate molecular weight of 26.9 kDa. The protein was then successfully crystallized using the sitting-drop vapour-diffusion method. The crystals diffracted to 1.9 angstrom resolution and belonged to space group P21, with unit-cell parameters a = 35.1, b = 69.5, c = 49.6A, alpha=gamma=90 degrees, beta=105.4 degrees.

Recent advances in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) was largely considered to be a disease of slow progression, standard treatment with Chlorambucil and having almost similar prognosis. With the introduction of molecular methods for understanding the disease pathophysiology in CLL there has been a remarkable change in the approach towards the disease. The variation in B-cell receptor response and immunoglobulin heavy chain variable region (IGHV) mutation, genetic aberration and defect in apoptosis and proliferation has had an impact on therapy initiation and prognosis. Early diagnosis of molecular variant is therefore necessary in CLL.

Clinical analysis on 40 patients with chronic lymphocytic leukemia / 中国实验血液学杂志

This study was aimed to analyze the clinical and laboratorial characteristics of patients with chronic lymphocytic leukemia (CLL), as well as their relationship with outcomes of patients. The clinical and laboratorial data of 40 CLL patients admitted from 2004 to 2010 in our hospital were analyzed retrospectively. The results indicated that the most of CLL attacked the elderly male patients with median age 66 (from 42 to 80). Flow cytometric analysis showed that 25 cases were positive for typical immunophenotype of CLL. On the other hand, all the patients clearly expressed CD19 and CD5, 7 cases (17.5%) and 14 cases (35%) were positive for the expression of CD38 and Zap70 respectively. 8 cases harbored a mutated immunoglobulin heavy-chain (VH) gene, among them 4 cases belong to VH3 family. Interphase FISH analysis showed that P53 deletion, RB1 deletion, trisomy 12 and normal chromosome were detected in 6, 3, 1, and 5 cases, respectively. The median PFS in 31 patients received treatment of fludarabine based chemotherapy was 48 months (95%CI: 39 - 57 months), among them 27 cases (87.1%) achieved CR + PR. While PFS was 14 months (95%CI: 10 - 18 months, P < 0.001) in 9 patients received other treatment regimen, out of them only 3 cases (33.3%) achieved CR + PR. Patients with normal level of serum β2-microglobulin at diagnosis showed significantly higher overall survival (78%, 95%CI: 69% - 87%) in 36 months than those with abnormal level of serum β2-microglobulin (47%, 95%CI: 35% - 59%, P = 0.004). Significant difference in the rate of CR + PR was noted in the Zap70 positive group (50%) and in negative group (88.5%, P = 0.006). All of 8 patients with IgVH mutation displayed CR after treatment, while 4 cases (66.7%) archived CR among 6 patients without IgVH mutation. It is concluded that CLL is characterized by high heterogeneity in both clinical features and molecular markers, which are associated with prediction of outcomes for patients. The treatment with fludarabine-based chemotherapy results in a major benefit and long survival for patients with CLL.

Ribosome display screening of a novel human anti-IgE scFv fragment / 药学学报

Total mRNA was extracted from lymphocytes separated from the peripheral blood of allergic patients, and then variable region of heavy chain (VH) and variable region of light chain (VL) cDNA library were constructed by RT-PCR. Human scFv templates for rabbit reticulocyte lysate ribosome display were assembled by primers and linker peptide (Gly4Ser)3. mRNA bound in antibody-ribosome-mRNA complexes was recovered using in-situ single primer RT-PCR, and three rounds of anti-IgE scFv DNA were enriched. The target DNA fragments were double enzyme digested and ligated into plasmid pET22b (+), followed by transformation in E. coli Rosseta (DE3). Positive clones were screened using clone PCR, Dot blotting and antigen ELISA. The correct lengths of VH (400 bp) and VL (710 bp) PCR products were obtained. The expected 1,000 bp ribosome display templates were also observed in agarose gel electrophoresis. After three rounds of ribosome display target sequences were effectively enriched, leading to a library of 10(13) members. Antibodies with the highest ELISA value for IgE were generated in the strain pET-IgE-6. A human anti-IgE scFv library was successfully constructed as described herein. Ribosome display using single primer in-situ RT-PCR as the recovery procedure effectively enriched target sequences. Anti-IgE scFv with high affinity and specificity were identified. The prepared human anti-IgE scFv fragment might be self-developed to a lead drug for treating asthma. Our study provides an alternative method for rapid discovery of human antibodies of therapeutic importance.

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 initiating both somatic hypermutation (SHM) and class switch recombination. A few research groups have successfully used the feature of AID for generating mutant libraries in directed evolution of target proteins in B cells in vitro. B cells, cultured in suspension, are not convenient 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-α scFv (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.

Overrepresentation of specific gene segments of expressed immunoglobulin heavy chain variable region among unmutated and mutated patients with chronic lymphocytic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the overrepresentation of specific gene segments of immunoglobulin heavy chain variable region (IgVH) among unmutated and mutated chronic lymphocytic leukemia (CLL) patients and its prognostic implication.</p><p><b>METHODS</b>Multiplex PCR was used to identify the expression of IgVH segment and its mutation status in CLL.</p><p><b>RESULTS</b>Analyses were successfully performed in 80 of 85 samples. Marked skewed IgVH families were disclosed. The most commonly used VH was VH3 (40.0%), followed by VH4 (30.0%), VHI (13.8%), VH2 (10.0%) and VH5, VH7 (2.5%). Fifty-six patients (70.0%) had mutated VH, 24 (30.0%) unmutated VH. Nine cases (11.3%) were with 100% germline sequence. Fifteen cases (15/24, 62.5%) in VH4, 29 (29/32, 90.7%) in VH3, and 4 (4/11, 36.3%) in VH1 had mutated VH. The most frequently used IgVH gene was VH4-39 (13.8%), and VH4-34 (8.8%). J4 (36/66, 54.5%) and D3 (25/66, 37.8%) were the most frequently used in J and D genes. The progression-free survival (PFS) was 82 and 17 months (P = 0.000), and the overall survival (OS) was 90 and 41 months (P = 0.009), respectively, for mutated and unmutated cases. Recurrent CDR3 sequences were found in our patients and 2 patients with VH1-69 had CDR3 sequences highly similar to those reported in literature.</p><p><b>CONCLUSION</b>There is difference in IgVH gene segment usage and mutational status in different area CLL patients. Recurrent CDR3 sequences were found in specific IgVH gene segments, which highlights the importance of immunoglobulin mediated stimulation in the development of CLL.</p>

γδ T lymphocyte function and the polymorphism of T cell receptor V δ chain in lungs of asthmatic patients / 中国医学科学院学报

<p><b>OBJECTIVE</b>To observe the function of gamma delta T lymphocytes and the polymorphism of T cell receptor V delta chain in the lungs of asthmatic patients and explore the role of gamma delta T cells in airway inflammation.</p><p><b>METHODS</b>Bronchoalveolar lavage fluid BALF was obtained from 7 asthmatic patients and 7 healthy control individuals. The percentage of gamma delta T cell in BALF was measured by flow cytometry. The gamma delta T cell in BALF was purified by magnetic labeled beads. Proliferous activity was examined by MTT assay. Cytokines secreted by gamma delta T cells in medium was assessed by enzyme-linked immunosorbent assay. Polymorphism of T cell receptor V delta chain was detected by RT-PCR and gene scan analysis.</p><p><b>RESULTS</b>The proportion of gamma delta T cell in the BALF of asthmatic patients [(6.39+/-0.71)%] was significantly higher than that in control subjects [(2.62+/-0.37)%] (P<0.01). The proportion of macrophage in the BALF of asthmatic patients [(81+/-4)] was significantly lower than that in control subjects [(86+/-2)] (P<0.05). The proliferation rate of asthmatic patients [(284.2+/-43.6)%] was significantly higher than that of control subjects [(217.5+/-59.5)%] (P<0.05). Interleukin-4 secreted by gamma delta T cells of asthmatic patients [(18.9+/-3.1) pg/ml)] significantly increased when compared with the control subjects [(14.1+/-3.0) pg/ml] (P<0.05). The polymorphism of T cell receptor V delta chain was not significantly different between these two groups.</p><p><b>CONCLUSIONS</b>The increase of gamma delta T cells in the lung of asthmatic patients further exacerbates Th1/Th2 disturbance and airway inflammation. Antigen recognition by gamma delta T cells is non-specific.</p>

Preparation and bioactivity of anti-human red blood cell ScFv and CSFV E2 bifunctional fusion protein / 生物工程学报

The aim of this study is to construct a bifunctional fusion protein, which can conjugate both human red blood cells and antibodies against classical swine fever virus (CSFV). We respectively amplified 2E8ScFv and mE2 genes from different recombinant vectors, in which 2E8ScFv gene is the single chain Fv gene against H antigen of human red blood cells, whereas mE2 gene is the main antigen coding region gene of CSFV E2 protein. We used overlap extension PCR to obtain an artificial fusion gene segment 2E8mE2 containing genes of Both 2E8ScFv and mE2, then ligated into the expression vector pET-DsbA and expressed in Escherichia coli BL21(DE3) PlysS host cells, after induced with IPTG the target fusion protein was successfully expressed and identified in inclusion bodies by SDS-PAGE and Western blotting. We purified the fusion protein and renatured it from inclusion bodies to obtain a native state of well biological activity. The Erythrocyte agglutination test results indicated that the fusion protein can conjugate both human red blood cells and antibodies of CSFV.

Preparation and characterization of human phage display antibody against peroxiredoxin I of lung adenocarcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a human phage antibody library and screen the single chain variable fragment (ScFv) antibudies to peroxiredoxin I (Prx I) of lung adenocarcinoma.</p><p><b>METHODS</b>The total RNA was isolated from the lymph nodes of lung cancer patients to amplify V(H) and V(L) genes by RT-PCR. V(H) and V(L) were linked with a DNA linker by SOE-PCR to construct the single chain variable fragment gene. The ScFvs were coloned into the phage vector pCANTAB5E. The insert ratio of the ScFv antibody library was identified by PCR, and the products were digested by SfiI/NotI and analyzed with 1% agarose gel electrophoresis. Three rounds of panning against lung adenocarcinoma cell line A549 and Prx I were performed, and the positive clones were identified for soluble expression. The soluble antibodies were identified by SDS-PAGE and Western blotting, and ELISA and immunocytochemistry were used to characterize the activity of the antibodies.</p><p><b>RESULTS</b>A recombination phage antibody library was constructed. The insert ratio of ScFv gene was 77% (23/30), and enzyme digestion identified the target product. The sixth phage harvest resulted in a yield 180 folds of that of the first one. Positive reactions to A549 cells were detected in 6 of 10 random clones, with a positivity rate of 60%. The soluble human ScFvs against Prx I of lung adenocarcinoma were expressed in E. coli HB2151 and confirmed by SDS-PAGE and Western blotting. ELISA and immunocytochemistry demonstrated a relative specific affinity of the soluble antibodies to A549 cells.</p><p><b>CONCLUSION</b>ScFv antibodies against lung adenocarcinoma have been acquired by phage display antibody library technique, and the soluble antibodies have a relative avidity specific to human lung adenocarcinoma A549 cells overexpressing PrxI.</p>