RESUMO
Chronic myelogenous leukemia (CML) is the most common type of leukemia in adults, and more than 90% of CML patients harbor the abnormal Philadelphia chromosome (Ph) that encodes the BCR-ABL oncoprotein. Although the ABL kinase inhibitor (imatinib) has proven to be very effective in achieving high remission rates and improving prognosis, up to 33% of CML patients still cannot achieve an optimal response. Here, we used CRISPR/Cas9 to specifically target the BCR-ABL junction region in K562 cells, resulting in the inhibition of cancer cell growth and oncogenesis. Due to the variety of BCR-ABL junctions in CML patients, we utilized gene editing of the human ABL gene for clinical applications. Using the ABL gene-edited virus in K562 cells, we detected 41.2% indels in ABL sgRNA_2-infected cells. The ABL-edited cells reveled significant suppression of BCR-ABL protein expression and downstream signals, inhibiting cell growth and increasing cell apoptosis. Next, we introduced the ABL gene-edited virus into a systemic K562 leukemia xenograft mouse model, and bioluminescence imaging of the mice showed a significant reduction in the leukemia cell population in ABL-targeted mice, compared to the scramble sgRNA virus-injected mice. In CML cells from clinical samples, infection with the ABL gene-edited virus resulted in more than 30.9% indels and significant cancer cell death. Notably, no off-target effects or bone marrow cell suppression was found using the ABL gene-edited virus, ensuring both user safety and treatment efficacy. This study demonstrated the critical role of the ABL gene in maintaining CML cell survival and tumorigenicity in vitro and in vivo. ABL gene editing-based therapy might provide a potential strategy for imatinib-insensitive or resistant CML patients.
RESUMO
Since imatinib (Glivec or Gleevec) has been used to target the BCR-ABL fusion protein, chronic myeloid leukemia (CML) has become a manageable chronic disease with long-term survival. However, 15%-20% of CML patients ultimately develop resistance to imatinib and then progress to an accelerated phase and eventually to a blast crisis, limiting treatment options and resulting in a poor survival rate. Thus, we investigated whether histone deacetylase inhibitors (HDACis) could be used as a potential anticancer therapy for imatinib-resistant CML (IR-CML) patients. By applying a noninvasive apoptosis detection sensor (NIADS), we found that panobinostat significantly enhanced cell apoptosis in K562 cells. A further investigation showed that panobinostat induced apoptosis in both K562 and imatinib-resistant K562 (IR-K562) cells mainly via H3 and H4 histone acetylation, whereas panobinostat targeted cancer stem cells (CSCs) in IR-K562 cells. Using CRISPR/Cas9 genomic editing, we found that HDAC1 and HDAC2 knockout cells significantly induced cell apoptosis, indicating that the regulation of HDAC1 and HDAC2 is extremely important in maintaining K562 cell survival. All information in this study indicates that regulating HDAC activity provides therapeutic benefits against CML and IR-CML in the clinic.
Assuntos
Proteínas de Fusão bcr-abl/genética , Histona Desacetilase 1/genética , Histona Desacetilase 2/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Acetilação/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Sistemas CRISPR-Cas/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Técnicas de Inativação de Genes , Inibidores de Histona Desacetilases/farmacologia , Humanos , Mesilato de Imatinib/efeitos adversos , Mesilato de Imatinib/farmacologia , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Panobinostat/farmacologiaRESUMO
Anaplastic thyroid carcinoma (ATC) and squamous thyroid carcinoma (STC) are both rare and advanced thyroid malignancies with a very poor prognosis and an average median survival time of 5 months and less than 20% of affected patients are alive 1 year after diagnosis. The clinical management of both ATC and STC is very similar because they are not particularly responsive to radiotherapy and chemotherapy. This inspired us to explore a novel and effective clinically approved therapy for ATC treatment. Histone deacetylase inhibitor (HDACi) drugs are recently FDA-approved drug for malignancies, especially for blood cell cancers. Therefore, we investigated whether an HDACi drug acts as an effective anticancer drug for advanced thyroid cancers. Cell viability analysis of panobinostat treatment demonstrated a significant IC50 of 0.075 µM on SW579 STC cells. In addition, panobinostat exposure activated histone acetylation and triggered cell death mainly through cell cycle arrest and apoptosis-related protein activation. Using CRISPR/Cas9 to knock out HDAC1 and HDAC2 genes in SW579 cells, we observed that the histone acetylation level and cell cycle arrest were enhanced without any impact on cell growth. Furthermore, HDAC1 and HDAC2 double knockout (KO) cells showed dramatic cell apoptosis activation compared to HDAC1 and HDAC2 individual KO cells. This suggests expressional and biofunctional compensation between HDAC1 and HDAC2 on SW579 cells. This study provides strong evidence that panobinostat can potentially be used in the clinic of advanced thyroid cancer patients.
Assuntos
Apoptose/genética , Histona Desacetilase 1/genética , Histona Desacetilase 2/genética , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/patologia , Acetilação , Apoptose/efeitos dos fármacos , Sistemas CRISPR-Cas , Linhagem Celular Tumoral , Edição de Genes , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Inativação de Genes , Inibidores de Histona Desacetilases/farmacologia , Histonas/metabolismo , Humanos , Metástase Neoplásica , Estadiamento de Neoplasias , Neoplasias da Glândula Tireoide/tratamento farmacológico , Neoplasias da Glândula Tireoide/metabolismoRESUMO
Anaplastic carcinoma of the thyroid (ATC), also called undifferentiated thyroid cancer, is the least common but most aggressive and deadly thyroid gland malignancy of all thyroid cancers. The aim of this study is to explore essential biomarker and use CRISPR/Cas9 with lentivirus delivery to establish a gene-target therapeutic platform in ATC cells. At the beginning, the gene expression datasets from 1036 cancers from CCLE and 8215 tumors from TCGA were collected and analyzed, showing EGFR is predominantly overexpressed in thyroid cancers than other type of cancers (P = 0.017 in CCLE and P = 0.001 in TCGA). Using CRISPR/Cas9 genomic edit system, ATC cells with EGFR sgRNA lentivirus transfection obtained great disruptions on gene and protein expression, resulting in cell cycle arrest, cell growth inhibition, and most importantly metastasis turn-off ability. In addition, the FDA-approved TKI of afatinib for EGFR targeting also illustrates great anticancer activity on cancer cell death occurrence, cell growth inhibition, and cell cycle arrest in SW579 cells, an EGFR expressing human ATC cell line. Furthermore, off-target effect of using EGFR sgRNAs was measured and found no genomic editing can be detected in off-target candidate gene. To conclude, this study provides potential ATC therapeutic strategies for current and future clinical needs, which may be possible in increasing the survival rate of ATC patients by translational medicine.
Assuntos
Sistemas CRISPR-Cas , Receptores ErbB/genética , Edição de Genes/métodos , Carcinoma Anaplásico da Tireoide/genética , Neoplasias da Glândula Tireoide/genética , Afatinib , Antineoplásicos/farmacologia , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Inibidores de Proteínas Quinases/farmacologia , Quinazolinas/farmacologiaRESUMO
Breast cancer is the most common malignancy in women and the second leading cause of cancer death in women. Triple negative breast cancer (TNBC) subtype is a breast cancer subset without ER (estrogen receptor), PR (progesterone receptor) and HER2 (human epidermal growth factor receptor 2) expression, limiting treatment options and presenting a poorer survival rate. Thus, we investigated whether histone deacetylation inhibitor (HDACi) could be used as potential anti-cancer therapy on breast cancer cells. In this study, we found TNBC and HER2-enriched breast cancers are extremely sensitive to Panobinostat, Belinostat of HDACi via experiments of cell viability assay, apoptotic marker identification and flow cytometry measurement. On the other hand, we developed a bioluminescence-based live cell non-invasive apoptosis detection sensor (NIADS) detection system to evaluate the quantitative and kinetic analyses of apoptotic cell death by HDAC treatment on breast cancer cells. In addition, the use of HDACi may also contribute a synergic anti-cancer effect with co-treatment of chemotherapeutic agent such as doxorubicin on TNBC cells (MDA-MB-231), but not in breast normal epithelia cells (MCF-10A), providing therapeutic benefits against breast tumor in the clinic.
Assuntos
Antineoplásicos/farmacologia , Bioensaio , Regulação Neoplásica da Expressão Gênica , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/genética , Ácidos Hidroxâmicos/farmacologia , Indóis/farmacologia , Sulfonamidas/farmacologia , Linhagem Celular Tumoral , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Citometria de Fluxo , Histona Desacetilases/metabolismo , Humanos , Glândulas Mamárias Humanas/efeitos dos fármacos , Glândulas Mamárias Humanas/metabolismo , Glândulas Mamárias Humanas/patologia , Panobinostat , Receptor ErbB-2/deficiência , Receptor ErbB-2/genética , Receptores de Estrogênio/deficiência , Receptores de Estrogênio/genética , Receptores de Progesterona/deficiência , Receptores de Progesterona/genética , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Neoplasias de Mama Triplo Negativas/genética , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
BACKGROUND: As cancer metastasis is the deadliest aspect of cancer, causing 90% of human deaths, evaluating the molecular mechanisms underlying this process is the major interest to those in the drug development field. Both therapeutic target identification and proof-of-concept experimentation in anti-cancer drug development require appropriate animal models, such as xenograft tumor transplantation in transgenic and knockout mice. In the progression of cancer metastasis, circulating tumor cells (CTCs) are the most critical factor in determining the prognosis of cancer patients. Several studies have demonstrated that measuring CTC-specific markers in a clinical setting (e.g., flow cytometry) can provide a current status of cancer development in patients. However, this useful technique has rarely been applied in the real-time monitoring of CTCs in preclinical animal models. METHODS: In this study, we designed a rapid and reliable detection method by combining a bioluminescent in vivo imaging system (IVIS) and quantitative polymerase chain reaction (QPCR)-based analysis to measure CTCs in animal blood. Using the IVIS Spectrum CT System with 3D-imaging on orthotropic-developed breast-tumor-bearing mice. RESULTS: In this manuscript, we established a quick and reliable method for measuring CTCs in a preclinical animal mode. The key to this technique is the use of specific human and mouse GUS primers on DNA/RNA of mouse peripheral blood under an absolute qPCR system. First, the high sensitivity of cancer cell detection on IVIS was presented by measuring the luciferase carried MDA-MB-231 cells from 5 to 5x1011 cell numbers with great correlation (R2 = 0.999). Next, the MDA-MB-231 cell numbers injected by tail vein and their IVIS radiance signals were strongly corrected with qPCR-calculated copy numbers (R2 > 0.99). Furthermore, by applying an orthotropic implantation animal model, we successfully distinguished xenograft tumor-bearing mice and control mice with a significant difference (p < 0.001), whereas IVIS Spectrum-CT 3D-visualization showed that blood of mice with lung metastasis contained more than twice the CTC numbers than ordinary tumor-bearing mice. We demonstrated a positive correlation between lung metastasis status and CTC numbers in peripheral mouse blood. CONCLUSION: Collectively, the techniques developed for this study resulted in the integration of CTC assessments into preclinical models both in vivo and ex vivo, which will facilitate translational targeted therapy in clinical practice.
Assuntos
Neoplasias da Mama/sangue , Neoplasias da Mama/genética , Imagem Molecular/métodos , Células Neoplásicas Circulantes/patologia , Animais , Biomarcadores Tumorais/sangue , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Modelos Animais de Doenças , Feminino , Citometria de Fluxo , Humanos , Camundongos , Metástase Neoplásica , Prognóstico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
OBJECTIVE Effective perioperative hand antisepsis is crucial for the safety of patients and medical staff in surgical rooms. The antimicrobial effectiveness of different antiseptic methods, including conventional hand scrubs and waterless hand rubs, has not been well evaluated. DESIGN, SETTING, AND PARTICIPANTS A randomized controlled trial was conducted to investigate the effectiveness of the 3 antiseptic methods among surgical staff of Taipei Medical University-Shuang Ho Hospital. For each method used, a group of 80 participants was enrolled. INTERVENTION Surgical hand cleansing with conventional 10% povidone-iodine scrub, conventional 4% chlorhexidine scrub, or waterless hand rub (1% chlorhexidine gluconate and 61% ethyl alcohol). RESULTS Colony-forming unit (CFU) counts were collected using the hand imprinting method before and after disinfection and after surgery. After surgical hand disinfection, the mean CFU counts of the conventional chlorhexidine (0.5±0.2, P<0.01) and waterless hand rub groups (1.4±0.7, P<0.05) were significantly lower than that of the conventional povidone group (4.3±1.3). No significant difference was observed in the mean CFU count among the groups after surgery. Similar results were obtained when preexisting differences before disinfection were considered in the analysis of covariance. Furthermore, multivariate regression indicated that the antiseptic method (P=.0036), but not other variables, predicted the mean CFU count. CONCLUSIONS Conventional chlorhexidine scrub and waterless hand rub were superior to a conventional povidone-iodine product in bacterial inhibition. We recommend using conventional chlorhexidine scrub as a standard method for perioperative hand antisepsis. Waterless hand rub may be used if the higher cost is affordable. Infect Control Hosp Epidemiol 2017;38:417-422.
Assuntos
Anti-Infecciosos Locais , Clorexidina , Desinfecção das Mãos/métodos , Higienizadores de Mão , Mãos/microbiologia , Povidona-Iodo , Contagem de Colônia Microbiana , Humanos , Enfermagem de Centro Cirúrgico , Método Simples-Cego , CirurgiõesRESUMO
BACKGROUND: Neonates are at a higher risk for bacterial meningitis than children of other age groups. Although the mortality rates have decreased over the past few decades, neonatal meningitis is still a severe disease with high morbidity. For bacterial meningitis, antibiotic therapy is the primary choice for management. However, neurologic complications often cannot be averted; â¼40% of survivors exhibit neurological sequelae. Escherichia coli infection is the common cause of neonatal meningitis. Previously, we have demonstrated that the recombinant loop 1-3, loop 2-3, and loop 2-4 fragments of OmpA protein can protect mice from death after intracerebral E. coli infection. In this study, the protective effects of the recombinant OmpA protein fragments in E. coli intracerebral infections were investigated. METHODS: The effects of E. coli intracerebral infection on cytokine and chemokine expression were determined. We also used various recombinant fragments of the OmpA protein to investigate the effects of these recombinant OmpA protein fragments on cytokine and chemokine expression. RESULTS: In this study, we demonstrated that the expression of interleukin-17 and other cytokines, chemokines, inducible nitric oxide synthase, and cyclooxygenase-2 are involved in the inflammatory processes of intracerebral E. coli infection. We also demonstrated that specific recombinant OmpA protein fragments (L1-3, L2-3, L2-4, and L3) can regulate cytokine, chemokine, nitric oxide synthase, and cyclooxygenase-2 expression and, subsequently, protect mice from death caused by intracerebral infection of E. coli. CONCLUSION: This finding indicates the potential for developing a new therapeutic approach to improve the prognosis of bacterial meningitis.
Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Ciclo-Oxigenase 2/imunologia , Escherichia coli/imunologia , Interleucina-17/biossíntese , Meningite devida a Escherichia coli/prevenção & controle , Óxido Nítrico Sintase Tipo II/imunologia , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/farmacologia , Animais , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/farmacologia , Linhagem Celular Tumoral , Ciclo-Oxigenase 2/biossíntese , Humanos , Recém-Nascido , Masculino , Meningite devida a Escherichia coli/imunologia , Meningite devida a Escherichia coli/microbiologia , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo II/biossíntese , RatosRESUMO
BACKGROUND AND AIMS: The glycoprotein (G protein) and fusion protein (F protein) of respiratory syncytial virus (RSV) both show genetic variability, but few studies have examined the F protein gene. This study aimed to characterize the molecular epidemiology and phylodynamics of the F protein gene in clinical RSV strains isolated in northern Taiwan from 2000-2011. METHODS: RSV isolates from children presenting with acute respiratory symptoms between July 2000 and June 2011 were typed based on F protein gene sequences. Phylogeny construction and evaluation were performed using the neighbor-joining (NJ) and maximum likelihood (ML) methods. Phylodynamic patterns in RSV F protein genes were analyzed using the Bayesian Markov Chain Monte Carlo framework. Selection pressure on the F protein gene was detected using the Datamonkey website interface. RESULTS: From a total of 325 clinical RSV strains studied, phylogenetic analysis showed that 83 subgroup A strains (RSV-A) could be further divided into three clusters, whereas 58 subgroup B strains (RSV-B) had no significant clustering. Three amino acids were observed to differ between RSV-A and -B (positions 111, 113, and 114) in CTL HLA-B*57- and HLA-A*01-restricted epitopes. One positive selection site was observed in RSV-B, while none was observed in RSV-A. The evolution rate of the virus had very little change before 2000, then slowed down between 2000 and 2005, and evolved significantly faster after 2005. The dominant subtypes of RSV-A in each epidemic were replaced by different subtypes in the subsequent epidemic. CONCLUSIONS: Before 2004, RSV-A infections were involved in several small epidemics and only very limited numbers of strains evolved and re-emerged in subsequent years. After 2005, the circulating RSV-A strains were different from those of the previous years and continued evolving through 2010. Phylodynamic pattern showed the evolutionary divergence of RSV increased significantly in the recent 5 years in northern Taiwan.
Assuntos
Filogenia , Infecções por Vírus Respiratório Sincicial/virologia , Vírus Sincicial Respiratório Humano/classificação , Proteínas Virais de Fusão/classificação , Teorema de Bayes , Linhagem Celular , Linhagem Celular Tumoral , Criança , Pré-Escolar , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/metabolismo , Evolução Molecular , Feminino , Variação Genética , Antígeno HLA-A1/imunologia , Antígeno HLA-A1/metabolismo , Antígenos HLA-B/imunologia , Antígenos HLA-B/metabolismo , Células Hep G2 , Humanos , Lactente , Recém-Nascido , Masculino , Epidemiologia Molecular , Dados de Sequência Molecular , Método de Monte Carlo , Infecções por Vírus Respiratório Sincicial/epidemiologia , Infecções por Vírus Respiratório Sincicial/imunologia , Vírus Sincicial Respiratório Humano/genética , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/metabolismo , Taiwan/epidemiologia , Proteínas Virais de Fusão/genéticaRESUMO
Escherichia coli is the major Gram-negative bacterial pathogen in neonatal meningitis. Outer membrane protein A (OmpA) is a conserved major protein in the E. coli outer membrane and is involved in several host-cell interactions. To characterize the role of OmpA in the invasion of astrocytes by E. coli, we investigated OmpA-positive and OmpA-negative E. coli strains. Outer membrane protein A E44, E105, and E109 strains adhered to and invaded C6 glioma cells 10- to 15-fold more efficiently than OmpA-negative strains. Actin rearrangement, protein tyrosine kinase, and phosphoinositide 3-kinase activation were required for OmpA-mediated invasion by E. coli. In vitro infection of C6 cells and intracerebral injection into mice of the E44 strain induced expression of the astrocyte differentiation marker glial fibrillary acidic protein and the inflammatory mediators cyclooxygenase 2 and nitric oxide synthase 2. After intracerebral infection with E44, all C57BL/6 mice died within 36hours, whereas 80% of mice injected with E44 premixed with recombinant OmpA protein survived. Astrocyte activation and neutrophil infiltration were reduced in brain tissue sections in the mice given OmpA. Taken together, these data suggest that OmpA-mediated invasion plays an important role in the early stage of E.coli-induced brain damage, and that it may have therapeutic use in E. coli meningitis.
Assuntos
Astrócitos/microbiologia , Proteínas da Membrana Bacteriana Externa/fisiologia , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/patologia , Escherichia coli/patogenicidade , Actinas/metabolismo , Animais , Astrócitos/fisiologia , Linhagem Celular Tumoral , Ciclo-Oxigenase 2/metabolismo , Infecções por Escherichia coli/mortalidade , Proteínas de Escherichia coli/fisiologia , Regulação Bacteriana da Expressão Gênica/fisiologia , Proteína Glial Fibrilar Ácida/metabolismo , Glioma , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo II/metabolismo , Fosfopiruvato Hidratase/metabolismo , Ratos , Transdução de Sinais/fisiologia , Análise de Sobrevida , Fatores de TempoRESUMO
The major concern for severe acute respiratory syndrome (SARS), caused by the SARS-associated coronavirus (SARS-CoV), is the lack of diagnostic and therapeutic agents. Using a phage display technology in a chicken system, high-affinity monoclonal antibody fragments against the SARS-CoV spike protein were characterized. Ten truncated spike protein gene fragments were expressed in Escherichia coli cells. Following the immunization of chickens with these recombinant spike proteins, two single-chain variable fragment (scFv) antibody libraries were established with short or long linkers to contain 5x10(7) and 9x10(6) transformants, respectively. After four rounds of panning selection, the scFv antibodies of randomly chosen clones were demonstrated by Coomassie blue staining, and verified by western blot analysis. In a comparison of nucleotide sequences with the chicken germline gene, we found that all clones varied in the complementarity-determining regions, that two scFv antibodies reacted significantly with SARS-CoV-infected Vero cells, and that those two specific scFv antibodies recognized the same region of the spike protein spanning amino acid residues 750-1000. In conclusion, the results suggest that the chicken scFv phage display system can be a potential model for mass production of high-affinity antibodies against the SARS-CoV spike protein.
Assuntos
Anticorpos Antivirais/imunologia , Região Variável de Imunoglobulina/imunologia , Glicoproteínas de Membrana/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , Proteínas do Envelope Viral/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Western Blotting , Galinhas , Chlorocebus aethiops , Regiões Determinantes de Complementaridade , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos , Região Variável de Imunoglobulina/química , Dados de Sequência Molecular , Biblioteca de Peptídeos , Proteínas Recombinantes/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/isolamento & purificação , Síndrome Respiratória Aguda Grave/virologia , Glicoproteína da Espícula de Coronavírus , Células VeroRESUMO
Severe acute respiratory syndrome (SARS) is a newly emergent human disease, which requires rapid diagnosis and effective therapy. Among antibody sources, immunoglobulin Y (IgY) is the major antibody found in chicken eggs and can be used as an alternative to mammalian antibodies normally used in research and immunotherapy. In this study, phage-expressing chicken monoclonal scFv antibody was chosen and characterized with phage display antibody technology. Truncated fragments of SARS-CoV spike protein were cloned in pET-21 vector and expressed in BL-21 Escherichia coli (E. coli) cells. After purification, the purity of these recombinant spike proteins was examined on SDS-PAGE and their identity verified with Western blot analysis using anti-his antibodies and sera from convalescent stage SARS-CoV-infected patients. Using these bacteria-derived proteins to immunize chickens, it was found that polyclonal IgY antibodies in the egg yolk and sera were highly reactive to the immunogens, as shown by Western blot and immunocytochemical staining analysis. A phage displaying scFv library was also established from spleen B cells of immunized chicken with 5 x 10(7) clones. After four panning cycles, the eluted phage titer showed a 10-fold increase. In sequence analysis with chicken germline gene, five phage clones reacted, with large dissimilarities of between 31 and 62%, in the complementarity-determining regions, one dominant phage 4S1 had strong binding to fragment Se-e, located between amino acid residues 456-650 of the spike protein and this particular phage had significantly strong binding to SARS-CoV-infected Vero E6 cells. Based on the results, we conclude that generating specific scFv-expressing phage binders with the phage display system can be successfully achieved and that this knowledge can be applied in clinical or academic research.
Assuntos
Região Variável de Imunoglobulina/imunologia , Glicoproteínas de Membrana/imunologia , Síndrome Respiratória Aguda Grave/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , Proteínas do Envelope Viral/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Galinhas , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos , Feminino , Humanos , Fragmentos de Imunoglobulinas/genética , Fragmentos de Imunoglobulinas/imunologia , Região Variável de Imunoglobulina/genética , Imunoglobulinas/imunologia , Glicoproteínas de Membrana/genética , Dados de Sequência Molecular , Biblioteca de Peptídeos , RNA Viral/química , RNA Viral/genética , Proteínas Recombinantes/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , Alinhamento de Sequência , Glicoproteína da Espícula de Coronavírus , Proteínas do Envelope Viral/genéticaRESUMO
STUDY OBJECTIVES: To report the efficacy and findings of a large-scale preventive screening program for severe acute respiratory syndrome-associated coronavirus (SARS-CoV) using amplification of the virus from a nasopharyngeal swab (NPS) obtained from the health-care workers (HCWs). DESIGN: A prospective observational study. SETTING: A medical center in Taiwan. PARTICIPANTS: Two hundred thirty HCWs. INTERVENTION: NPS examination for the presence of SARS-CoV by two nested reverse transcription-polymerase chain reaction (RT-PCR) assays. MEASUREMENTS AND RESULTS: During the outbreak of severe acute respiratory syndrome (SARS), NPS polymerase chain reaction screening of HCWs for SARS-CoV was performed. SARS-CoV was examined by two nested RT-PCRs and a quantitative RT-PCR. Serum-specific antibodies were assessed by enzyme immunoassay and indirect immunofluorescence. We monitored 230 HCWs, including 217 first-line HCWs and 13 non-first-line HCWs. One hundred ninety first-line HCWs and 13 non-first-line HCWs had negative results in both nested RT-PCR assays. Two first-line HCWs who were positive on both nested RT-PCR assays had SARS. They had 16,900 +/- 7,920 copies (mean +/- SD) of RNA per milliliter in the NPS and had detectable anti-SARS antibodies. The remaining 25 first-line HCWs were negative for the first nested RT-PCR but positive for the second nested RT-PCR. Their corresponding titers were 338 +/- 227 copies of RNA per milliliter; antibodies developed in none of these 25 HCWs. The expression and function of angiotensin-converting enzyme-2 were not different among these HCWs. This study shows that colonization of SARS-CoV occurred in 25 of 217 well-protected first-line HCWs on a SARS-associated service, but they remained seronegative. CONCLUSION: With the second RT-PCR assay more sensitive than the first RT-PCR assay, we are able to show that approximately 11.5% of well-protected HCWs exposed to SARS patients or specimens may have colonization without seroconversion. Only those with significant clinical symptoms or disease would have active immunity. Thus, regular NPS screening for nested RT-PCR assays in conjunction with a daily recording of body temperature in all first-line HCWs may provide an effective way of early detection.