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In the quality control of Chinese medicine, the detection of active components and toxic and harmful components are two important links. Although conventional methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry can accurately quantify the above substances, they have shortcomings such as complicated operation, high costs, inability of detection at any time, difficult detection of insoluble and macromolecular substances. Enzyme-linked immunosorbent assay (ELISA) can adsorb antigens or antibodies on the surface of solid carriers and realize qualitative or quantitative analysis of targets by using the specific reactions of antigens and antibodies. This method is praised for the simple operation, high sensitivity, strong specificity, simple requirements for experimental equipment, a wide application range, and low costs. In recent years, ELISA has been widely used in the quality control of Chinese medicine, especially in the content determination of mycotoxins represented by aflatoxin and the qualitative and quantitative analysis of active components. ELISA plays an increasingly important role with its unique advantages, providing new methods and ideas for the rapid quality examination of large quantities of Chinese medicines. This paper reviews the research progress in ELISA for the quality control of Chinese medicine in recent years and prospects its technical development and application prospects, aiming to provide reference and research ideas for further using this method to ensure the quality, safety, and controllability of Chinese medicine.
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@#Objective To establish and verify a universal and stable potency test method in vitro for SARS-CoV-2 mRNA vaccine,so as to use it for the quality control of SARS-CoV-2 mRNA vaccine.Methods ELISA kits that could bind well to S protein of SARS-CoV-2 variants,as well as transfected cells,cell plating concentrations and doses for transfection were screened,and then a potency test method for SARS-CoV-2 mRNA vaccine in vitro was established and verified.Results An ELISA kit was found with good binding ability to S protein of each variant,and HEK293T cells were determined as the transfection cells,with the plating concentration of 2.5 × 10~5 cells/mL and the transfection dose of 4 μg/well in the 6-well plate.An universal and stable potency test method for SARS-CoV-2 mRNA vaccine in vitro was established.The verification results showed that the method met the quality control needs.Conclusion The established potency test method in vitro for SARS-CoV-2 mRNA vaccine has good relative accuracy,linearity,intermediate precision and range,and can be applied to the quality control of SARS-CoV-2 mRNA vaccines
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Objective To investigate the changes and clinical significance of serum tumor necrosis fac-tor-α(TNF-α),adiponectin(ADP)and their ratio in patients with depression.Methods A total of 40 patients with depression admitted to Shandong Daizhuang Hospital from January to December 2020 were selected as the observation group,and 26 healthy volunteers were selected as the control group.The observation group was treated with oral antidepressants for four weeks,and the severity of depressive symptoms was assessed by Hamilton depression scale(HAMD).The levels of serum TNF-α and ADP in the observation group before and after treatment and the control group were detected by ELISA,and the change of TNF-α/ADP was ana-lyzed.Results HAMD scores of the observation group were 25.5(21.0,30.0)before treatment and 2.0(1.0,4.0)after treatment,the difference was statistically significant(P<0.05).The levels of TNF-α and TNF-α/ADP in the observation group before treatment were higher than those in the control group,which af-ter treatment were also higher than those before treatment(P<0.05).The level of ADP in the observation group after treatment was lower than that before treatment and in the control group,the differences were sta-tistically significant(P<0.05).Conclusion The level of TNF-α/ADP in patients with depression is more ob-vious than TNF-α.
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OBJECTIVE To investigate the effect of SAMC on the killing function of CD8+T cells against nasopharyngeal carcinoma cells and its mechanism.METHODS HK-1 and C666-1 are divided into 0,25,50,and 100 mol/L SAMC group,Western blot was used to detcet PD-L1 expression in tumor cells.CD8+T cells were co-cultured with HK-1 and C666-1 cells in a ratio of 10∶1,and 0,25,50,and 100 μmol/L SAMC were added and detect the killing ability of CD8+T on HK-1 and C666-1.ELISA was used to detect INF-γ and TNF-α concentration.Construct a subcutaneous transplant tumor model of nasopharyngeal HK-1 cells,and divide it into a control group,CD8+T cell group,SAMC group,and SAMC+CD8+T cell group.The tumor volume was measured during treatment in each group of mice.Western blot was used to detect the expression of PD-L1 in the tumor tissue,ELISA was used to detect INF-γ and TNF-α concentration of mouse serum.RESULTS Compared to 0 μmol/L SAMC group,the expression of PD-L1 in 25,50,100μmol/L SAMC group were significantly downregulated(P<0.05).Compared to 0 μmol/L SAMC+CD8+T group,the INF-γ and TNF-α concentration were significantly increased in 25,50,100 μmol/L SAMC+CD8+T group,the lysis rates of HK-1 and C666-1 cells were significantly increased.Compared with the control group,the tumor volume and weight in the CD8+T cell group and SAMC+CD8+T cell group were significantly reduced(P<0.05),the concentration of INF-γ and TNF-α were significantly increased.Compared with the CD8+T cell group,the tumor volume and weight in the SAMC+CD8+T cell group mice significantly decreased(P<0.05),while the serum INF-γ and TNF-α concentration significantly increased(P<0.05),and the expression of PDL-1 in tumor tissue was significantly downregulated(P<0.01).CONCLUSION SAMC can promote the killing function of CD8+T cells by inhibiting the expression of PD-L1 in human nasopharyngeal carcinoma cells.
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Objective To investigate the effects and mechanisms of peimine(PME)on chronic obstructive pulmonary disease(COPD)in mice.Methods The mice were randomly divided into 4 groups(20 mice in each group),control group,PME group,chronic obstructive pulmonary disease group and treatment group.Animal models of COPD were induced in mice by lipopolysaccharide combined with smoke.The effects of PME on COPD model mice was analyzed by HE staining,transmission electron microscopy and the ratio of wet/dry weight of mouse lung tissue.The effects of PME on COPD model mice were analyzed by HE staining,transmission electron microscopy and the ratio of wet/dry weight of mouse lung tissue.The effects of PME on inflammatory factor tumor necrosis factor(TNF)-α,interleukin(IL)-6 and IL-1β in lung tissue were analyzed by ELISA and Western blotting.The effects of PME on oxidative stress in lung tissue were analyzed by dihydroethidium(DHE)staining and Western blotting.The effects of PME on nuclear factor kappa-B(NF-κB)pathway and nuclear factor erythroid 2-related factor 2(Nrf2)pathway were analyzed by protein immunoblotting.Results Compared with the COPD group,PME treatment could significantly improve the lung tissue injury and the number of inflammatory cells in mice,and the wet/dry weight ratio of lung tissue was significantly reduced.Compared with the control group,the levels of TNF-α,IL-6 and IL-1β in the alveolar lavage fluid of COPD mice significantly increased,and the level of TNF-α,IL-6 and IL-1β in the alveolar lavage fluid of mice after PME treatment was significantly reduced.In addition,compared with the control group,the protein expression of TNF-α,IL-6 and IL-1β in the lung tissue of COPD mice significantly increased,and the level of TNF-α,IL-6 and IL-1β in the lung tissue of COPD mice after PME treatment were significantly reduced.Immunohistochemistry and Western blotting showed that the level of superoxide dismutase 2(SOD2)protein in COPD group was significantly lower than that in control group,while PME treatment could improve the level of superoxide dismutase protein.The analysis of MDA content in lung tissue showed that compared with the COPD group,the production of MDA in lung tissue of COPD mice was significantly inhibited after PME treatment.Protein Western blotting showed that PME treatment could prevent the phosphorylation of inhibitor of NF-κB(IκBα)and the transfer of NF-κB p65 to the cell nucleus,and the expression of Nrf2 and its main downstream target heme oxygenase-1(HO-1)in the lung tissue of mice treated with PME significantly increased.Conclusion PME is able to inhibit inflammation and oxidative stress and improve lung tissues damage in the COPD model in vivo and this protection effect might be both the Nrf2 pathway activation and NF-κB pathway inhibition.
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@#Objective To establish and verify a universal and stable potency test method in vitro for SARS-CoV-2 mRNA vaccine,so as to use it for the quality control of SARS-CoV-2 mRNA vaccine.Methods ELISA kits that could bind well to S protein of SARS-CoV-2 variants,as well as transfected cells,cell plating concentrations and doses for transfection were screened,and then a potency test method for SARS-CoV-2 mRNA vaccine in vitro was established and verified.Results An ELISA kit was found with good binding ability to S protein of each variant,and HEK293T cells were determined as the transfection cells,with the plating concentration of 2.5 × 10~5 cells/mL and the transfection dose of 4 μg/well in the 6-well plate.An universal and stable potency test method for SARS-CoV-2 mRNA vaccine in vitro was established.The verification results showed that the method met the quality control needs.Conclusion The established potency test method in vitro for SARS-CoV-2 mRNA vaccine has good relative accuracy,linearity,intermediate precision and range,and can be applied to the quality control of SARS-CoV-2 mRNA vaccines.
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@#Objective To develop and verify a double-antibody sandwich ELISA method for the detection of process-specific E.coli residual protein in recombinant biological preparations.Methods Taking the production and purification process of glucagon-like peptide(GLP)expressed by E.coli as the specific process model,the same process was used to intercept the residual protein of empty E.coli(normal E.coli that does not express recombinant protein). One female New Zealand white rabbit and six female Kunming mice were immunized with the residual protein as the immunogen. Using the IgG antibody purified from rabbit immune serum as the coating antibody,mouse immune serum as the second sandwich antibody,and antimouse IgG-HRP as the enzyme-labeled secondary antibody,a double antibody sandwich ELISA method for process-specific residual protein of E.coli was established. The specificity,accuracy and precision of the method were verified,and the limit of detection(LOD)was determined. Simultaneously,the developed method and the commercial E.coli host protein residue detection kit were used to quantitatively determine the residual protein of purified GLP preparation.Results After a series of gradient dilution of process-specific residual protein with known concentration,the sensitivity of this ELISA method reached 338 pg/mL. No cross reaction occurred in the detection of CHO and yeast cell lysis protein by this method,the recoveries of samples with low,medium and high concentrations were all in the range of 80% — 120%,and the intra-assay and inter-assay CVs of the empty E.coli interception standard with low,medium and high concentrations were all less than15%. For the residual protein in GLP preparation,about 62% of the residual proteins were not detected by the commercial non-process-specific ELISA kit compared with the total amount of residual proteins detected by the developed method,and these residual proteins should be the process-specific residual proteins.Conclusion The double antibody sandwich ELISA method developed in this study has high sensitivity,strong specificity,good accuracy and precision for the detection of process-specific E.coli residual protein,which can meet the detection requirements that the residual protein is less than0. 01% — 0. 1% in biological preparations.
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Background: Advanced glycation end products (AGEs) in diabetic patients can trigger several autoimmune responses. This article aims to assess the presence of circulating autoantibodies against glycated histones and their role in complications in diabetic patients in the Saudi population. Methods: A total of one hundred twenty samples were collected from diabetic patients with different age groups and healthy individuals as control. All serum samples were collected from Prince Sultan Military Medical City (PSMMC) in Riyadh City in Saudi Arabia. Glycated H2A was prepared and characterized using different physiochemical techniques. Then, ELISA was performed to assess the presence of circulating autoantibodies against glycated histones in diabetic patients’ samples compared with control healthy individuals in the Saudi population. Results: The glycation of H2A under our experimental conditions appears to be completed in 14 days. also, our data showed high circulating autoantibodies were detected against glycated H2A in all diabetic patients’ plasma with different dilutions. Remarkably, diabetic patients’ group 1 (under 20 years old group) showed highly significant binding activity values in each dilution. However, diabetic patients in groups 2 and 3 showed less binding but still significant values when compared to control healthy individuals. Conclusions: This finding provides novel perspectives into existing of circulating autoantibodies against glycated histones in diabetes patients in Saudi Arabia. Therefore, these circulating autoantibodies might be used as valuable tools for understanding the glycation mechanisms in diabetic patients in addition to providing diagnostic and prognostic knowledge. However, their roles in diabetic complications need further investigation.
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Resumen Objetivo: Establecer un inmunoensayo semicuantitativo para la detección de anticuerpos contra el dominio de unión al receptor de la proteína de espícula del coronavirus del síndrome respiratorio agudo grave tipo 2 y la evaluación de su desempeño como herramienta de apoyo diagnóstico. Métodos: Se generó una proteína recombinante del dominio de unión a receptor de la proteína de espícula del coronavirus del síndrome respiratorio agudo grave tipo 2. Dicha proteína se empleó como sustrato antigénico en la estandarización de dos ensayos semicuantitativos por inmunoadsorción ligados a enzima para la detección de inmunoglobulinas M e inmunoglobulinas G humanas. Se utilizó un conjunto de muestras de suero positivas (n=129), provenientes de donantes voluntarios con infección previa por el virus SARS-CoV-2, confirmada mediante reacción en cadena de la polimerasa con transcriptasa reversa, y tomadas entre agosto de 2020 y noviembre de 2021. Además, se empleó un panel de muestras prepandémicas negativas (n=196) obtenidas antes de diciembre de 2019 para la evaluación del desempeño de los ensayos; se recibieron muestras múltiples seriadas de 99 donantes voluntarios para examinar la respuesta de la prueba ante la seroconversión y se estudió la posible asociación entre las seropositividades por coronavirus del síndrome respiratorio agudo grave tipo 2 y por el virus del dengue para la evaluación de reacciones cruzadas inespecíficas. Resultados: El ensayo de detección de inmunoglobulina G mostró 81.4 % de sensibilidad, 86.2 % de especificidad y valores predictivos positivos y negativos de 79.5 % y 87.6 % respectivamente. Por su parte, el ensayo de detección de inmunoglobulina M mostró solamente 72.1 % de sensibilidad, 54.1 % de especificidad y valores predictivos positivos y negativos de 25.6 % y 89.8 % respectivamente. No se encontraron diferencias significativas entre las mediciones semicuantitativas según sexo ni correlación lineal entre esta variable y la edad. Los valores obtenidos para el inmunoensayo presentaron diferencias significativas según el autorreporte de presencia o ausencia de síntomas compatibles con COVID-19. No se encontró correlación entre las seropositividades contra el coronavirus del síndrome respiratorio agudo grave tipo 2 y el virus del dengue. El ensayo de detección de inmunoglobulina G generó valores inferiores pero constantes en muestras de donantes voluntarios que autorreportaron no haber tenido contacto con el virus SARS-CoV-2. En contraste, las muestras de donantes expuestos al virus SARS-CoV-2 mostraron valores elevados pero variables en magnitud. Además, se observaron valores elevados y variables en muestras de voluntarios vacunados o con infección previa. Conclusiones: Nuestro ensayo de detección de inmunoglobulina M presenta escaso valor diagnóstico. Por el contrario, el ensayo de detección de inmunoglobulina G muestra un rendimiento satisfactorio y se apega al comportamiento reportado para este tipo de prueba según las características demográficas y clínicas de los usuarios; por lo tanto, este ensayo podría ser empleado como herramienta fiable y práctica en aplicaciones clínicas y como apoyo al diagnóstico. Es necesario desarrollar más estudios sobre reacciones cruzadas entre los anticuerpos contra el coronavirus del síndrome respiratorio agudo grave tipo 2 con aquellos de otras entidades de interés clínico, sobre todo las presentes en países tropicales como el nuestro.
Abstract Aim: To establish a semiquantitative immunoassay for antibody detection against the RBD of the severe acute respiratory syndrome coronavirus 2 spike protein and to evaluate its performance to be used as a diagnostic supporting tool. Methods: A recombinant severe acute respiratory syndrome coronavirus 2 spike protein was produced. This protein was used as antigenic substrate in two semiquantitative enzyme-linked immunoassays for the detection of human immunoglobulins M and immunoglobulins G. A set of serum samples (N=129) from patients with prior viral infection confirmed by reverse transcription polymerase chain reaction, processed between August 2020 and November 2021, were used as positive samples. A panel of pre-pandemic samples (N=196), obtained prior to December 2019, were used as negative samples to evaluate the assay performance. Multiple samples from 99 volunteers were used to examine test response to seroconversion. The interference between seropositivity against severe acute respiratory syndrome coronavirus 2 and dengue virus was also evaluated. Results: The immunoglobulin G detection assay showed 81.4% sensitivity, 86.2% specificity, and positive and negative predictive values of 79.5% and 87.6% respectively. The immunoglobulin M detection assay yielded 72.1% sensitivity, 54.1% specificity, and positive and negative predictive values of 25.6% and 89.8% respectively. No significant differences were found between the measurements according to sex or linear correlation between this variable and age. The values presented significant differences according to the condition of self-reported presence or absence of COVID-19 like symptoms. No correlation was found between seropositivity for severe acute respiratory syndrome coronavirus 2 and dengue virus. The immunoglobulin G detection assay generated lower but constant values on samples from voluntary donors who reported not having any contact with the virus compared to samples from donors exposed to it, and high but variable values in magnitude on samples from vaccinated volunteers or those with previous severe acute respiratory syndrome coronavirus 2 infection compared to samples from donors without exposure to the viral antigen. Conclusions: Our established immunoglobulin M detection assay presents poor diagnostic value. On the other hand, the immunoglobulin G detection assay shows satisfactory performance, and coheres to the behavior reported for this type of test according to the demographic and clinic characteristics of the volunteer, so it could be used as a reliable and practical tool in clinical applications and as diagnostic complement. It is necessary to develop more studies on cross-reactions of antibodies against severe acute respiratory syndrome coronavirus 2 with other entities of clinical interest and present in our tropical area.
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Humans , Male , Female , Child, Preschool , Child , Adolescent , Adult , Middle Aged , Aged , Immunoassay , SARS-CoV-2/immunology , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Enzyme-Linked Immunosorbent Assay/trends , Costa Rica , COVID-19ABSTRACT
Background & objectives: The diagnosis of scrub typhus (ST) is usually done using enzyme-linked immunosorbent assay (ELISA) due to its ease of performance and reading objectivity. The cut-off value for ELISA needs to be calculated for each geographical location as it depends on zonal endemicity of the disease. This study was, therefore, undertaken to calculate the pan-India cut-off for anti-Orientia tsutsugamushi (OT) immunoglobulin M (IgM) by ELISA. Methods: Samples from cases (cases of ST) and controls (voluntary, consenting, healthy adults) were collected by a network of 29 laboratories across India and tested for anti-OT IgM by immunofluorescence assay (IFA), the considered gold standard test. These samples were retested by ELISA for anti-OT IgM and their optical densities (ODs) were used for cut-off estimation by receiver operating characteristic (ROC) curve. Results: Anti-OT IgM ELISA ODs from 273 controls and 136 cases were used for the cut-off estimation. The ODs of the anti-OT IgM ELISA on healthy individuals and those of confirmed ST cases ranged from 0.1 to 0.75 and 0.5 to 4.718, respectively. ROC curve-based cut-off for ELISA was calculated as 0.554 at a sensitivity of 95.2 per cent and specificity of 95.1 per cent. A value of >1 was noted to have a specificity of 100 per cent in diagnosing ST. Interpretation & conclusions: The cut-off calculated for India was similar to the previous cut-off that was used until now.
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Background: Allergic bronchopulmonary mycosis (ABPM) is a clinical syndrome associated with immune sensitivity to various fungi. Aspergillus spp. predominates in colonizing the airways of asthmatics. Early and accurate identification of fungus in such cases can prevent worsening of asthma. Also, can help in retarding the progression of ABPM. Objectives of this study were to evaluate different fungal allergens associated with clinically diagnosed Asthma patients by Skin Prick testing (SPT), to study total IgE in asthmatic patients by serological testing and to characterize the fungal isolate associated with SPT+ cases by conventional mycological culture. Methods: A prospective study of known asthma cases was done. Their sensitivity to fungal allergens was tested by SPT. The total IgE levels were measured by ELISA. Sputum collected from SPT+ cases were subjected for fungal identification. Results: Out of 175 patients, 25 (14.2%) showed positive reaction against fungal antigens in which fungal growth was seen in 21 (84%) sputum specimens. Aspergillus fumigatus was isolated from 16 (76%) specimens followed by Candida albicans in 3 (14%) and Penicillium spp in 2 (9.5%) cases. Out of 25 SPT+ asthmatics, 21 patients with fungal growth had total IgE levels >600 IU/ml and 4 patients with negative culture had IgE levels 400-500 IU/ml. Conclusions: A significant prevalence of fungal asthma is seen among asthmatics. Thus, it is essential to screen asthma patients for fungal allergy. SPT seems to be a good screening test. SPT is easy to perform, less time consuming and inexpensive however needs to be performed under pulmonologist’s supervision.
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Background: Allergic bronchopulmonary mycosis (ABPM) is a clinical syndrome associated with immune sensitivity to various fungi. Aspergillus spp. predominates in colonizing the airways of asthmatics. Early and accurate identification of fungus in such cases can prevent worsening of asthma. Also, can help in retarding the progression of ABPM. Objectives of this study were to evaluate different fungal allergens associated with clinically diagnosed Asthma patients by Skin Prick testing (SPT), to study total IgE in asthmatic patients by serological testing and to characterize the fungal isolate associated with SPT+ cases by conventional mycological culture. Methods: A prospective study of known asthma cases was done. Their sensitivity to fungal allergens was tested by SPT. The total IgE levels were measured by ELISA. Sputum collected from SPT+ cases were subjected for fungal identification. Results: Out of 175 patients, 25 (14.2%) showed positive reaction against fungal antigens in which fungal growth was seen in 21 (84%) sputum specimens. Aspergillus fumigatus was isolated from 16 (76%) specimens followed by Candida albicans in 3 (14%) and Penicillium spp in 2 (9.5%) cases. Out of 25 SPT+ asthmatics, 21 patients with fungal growth had total IgE levels >600 IU/ml and 4 patients with negative culture had IgE levels 400-500 IU/ml. Conclusions: A significant prevalence of fungal asthma is seen among asthmatics. Thus, it is essential to screen asthma patients for fungal allergy. SPT seems to be a good screening test. SPT is easy to perform, less time consuming and inexpensive however needs to be performed under pulmonologist’s supervision.
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ObjectiveTo investigate the mechanism of Magnolia officinalis cortex for constipation-type irritable bowel syndrome(IBS-C) rats before and after sweating. MethodIBS-C rat model was established by gavage of ice water, and rats were randomly divided into the blank group, model group, mosapride group(1 mg·kg-1), M. officinalis cortex group(10 g·kg-1) and sweated M. officinalis cortex group(10 g·kg-1). The changes of body weight, fecal number and fecal water content of rats were observed, 16S rRNA sequencing was used to detect the structural changes of fecal intestinal flora in rats, the levels of 5-hydroxytryptamine(5-HT) and substance P(SP) in colonic tissues of rats were determined by enzyme-linked immunosorbent assay(ELISA). ResultCompared with the model group, the fecal water content and fecal number of mosapride group, M. officinalis cortex group and sweated M. officinalis cortex group were significantly increased(P<0.05). At the phylum level, the top four species of flora abundance were Firmicutes, Bacteroidetes, Spirochaetes and Proteobacteria. Compared with the blank group, the proportion of Firmicutes in the model group was significantly reduced(P<0.05), while the proportion of Spirochaetes was significantly increased(P<0.05). Compared with the model group, the proportion of Firmicutes and Spirochaetes in M. officinalis cortex group and sweated M. officinalis cortex group tended to be similar to that in the blank group, and the proportion of Spirochaetes in sweated M. officinalis cortex group was lower than that of M. officinalis cortex group. At the family level, the top four species of flora abundance were Lactobacillaceae, S24_7, Ruminococcaceae, Bacteroidaceae, compared with the blank group, the proportion of Lactobacillaceae in the model group decreased significantly(P<0.05), and its proportion in the M. officinalis cortex group and sweated M. officinalis cortex group increased significantly after administration(P<0.05), and the flora structure of the two groups tended to be similar to that of the blank group. At the genus level, the top four species of flora abundance were Lactobacillus, Unspecified_S24_7, Bacteroides and Treponema. Compared with the blank group, the proportion of Lactobacillus in the model group decreased significantly(P<0.05), while the proportion of Treponema increased significantly(P<0.05). Compared with the model group, ratio of bacterial structure of Lactobacillus and Treponema in the M. officinalis cortex group and sweated M. officinalis cortex group tended to be similar to those in the blank group, indicating that M. officinalis cortex could restore the intestinal microbial structure of IBS-C rats before and after sweating. Compared with the model group, the 5-HT content in mosapride group was significantly reduced(P<0.05), the contents of 5-HT and SP in the M. officinalis cortex group and sweated M. officinalis cortex group were significantly increased(P<0.01), and the sweated M. officinalis cortex group was higher than the M. officinalis cortex group. ConclusionM. officinalis cortex can play a therapeutic role on IBS-C rats by regulating 5-HT pathway and intestinal flora structure before and after sweating.
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@#ObjectiveTo develop and verify a double antibody sandwich ELISA for the quantitative detection of varicellazoster virus(VZV)glycoprotein E(gE).MethodsHybridoma cell lines secreting antibody against VZV-gE stably were screened by mouse hybridoma fusion technology,using VZV whole virus antigen as immunogen.The antibody titer in mouse ascites was detected by indirect ELISA.After purified by Hi Trap2=0.995 6,P=0.000 1)。结论 建立的双抗体夹心ELISA法具有良好的准确性、精密性和特异性,可用于VZV疫苗中g E抗原含量的快速检测。 ObjectiveTo develop and verify a double antibody sandwich ELISA for the quantitative detection of varicellazoster virus(VZV)glycoprotein E(gE).MethodsHybridoma cell lines secreting antibody against VZV-gE stably were screened by mouse hybridoma fusion technology,using VZV whole virus antigen as immunogen.The antibody titer in mouse ascites was detected by indirect ELISA.After purified by Hi Trap(TM)Mabselect(TM)Mabselect(TM)Su Re and Hi Trap(TM)Su Re and Hi Trap(TM)Desalting,monoclonal antibodies(m Abs)were analyzed for the purity by 12%SDS-PAGE,detected for the specificity by Western blot,and identified for the subtype by mouse monoclonal antibody typing kit.Capture antibody and enzyme-labeled antibody were screened by epitope superposition test,which were determined for the working concentrations by chessboard titration(capture antibody concentrations were 0.25,0.5,1,2,5 and 10μg/m L,enzyme-labeled antibody dilutions were 1∶500,1∶1 000,1∶2 000,1∶5 000 and 1∶10 000),and then a double antibody sandwich ELISA(DAS-ELISA)was developed for the detection of VZV-gE content.In addition,the linear range,accuracy,precision and specificity of the method were verified.The gE content in the supernatant of 3 batches of CHO-VZV-gE cells cultured in 7 L bioreactor for 1~14 d were detected by the developed method.ResultsFour positive hybridoma cell lines secreting specific antibodies against VZV-gE stably were obtained and named as m Ab-B2,m Ab-11,K9C7 and K9F4.The antibodies in mouse ascites showed titers of10(TM)Desalting,monoclonal antibodies(m Abs)were analyzed for the purity by 12%SDS-PAGE,detected for the specificity by Western blot,and identified for the subtype by mouse monoclonal antibody typing kit.Capture antibody and enzyme-labeled antibody were screened by epitope superposition test,which were determined for the working concentrations by chessboard titration(capture antibody concentrations were 0.25,0.5,1,2,5 and 10μg/m L,enzyme-labeled antibody dilutions were 1∶500,1∶1 000,1∶2 000,1∶5 000 and 1∶10 000),and then a double antibody sandwich ELISA(DAS-ELISA)was developed for the detection of VZV-gE content.In addition,the linear range,accuracy,precision and specificity of the method were verified.The gE content in the supernatant of 3 batches of CHO-VZV-gE cells cultured in 7 L bioreactor for 1~14 d were detected by the developed method.ResultsFour positive hybridoma cell lines secreting specific antibodies against VZV-gE stably were obtained and named as m Ab-B2,m Ab-11,K9C7 and K9F4.The antibodies in mouse ascites showed titers of106~106~107with purities of about 97%after purification,which all specifically bound to VZV whole virus protein with light chains ofκchain and heavy chains of Ig G_(2b),Ig G_1,Ig G_(2b)and Ig G_(2a)respectively.m Ab-B2 was determined as capture antibody and HPR-labeled m Ab-11 as enzyme-labeled antibody with the optimum working concentrations of 1.5μg/m L and 1∶5 000respectively.The internal reference concentration of gE antigen was in the range of 1.95~1 000 ng/m L,which showed a good linear relationship with A_(450).The four-parameter equation was Y=(0.15-3.99)/[1+(X/67.4)7with purities of about 97%after purification,which all specifically bound to VZV whole virus protein with light chains ofκchain and heavy chains of Ig G_(2b),Ig G_1,Ig G_(2b)and Ig G_(2a)respectively.m Ab-B2 was determined as capture antibody and HPR-labeled m Ab-11 as enzyme-labeled antibody with the optimum working concentrations of 1.5μg/m L and 1∶5 000respectively.The internal reference concentration of gE antigen was in the range of 1.95~1 000 ng/m L,which showed a good linear relationship with A_(450).The four-parameter equation was Y=(0.15-3.99)/[1+(X/67.4)(1.49)]+3.99,and R(1.49)]+3.99,and R2value was 0.999.The recoveries of accuracy verification were 94.9%~114.0%;The coefficients of variation(CVs)of precision verification were all less than 15%.Except CHO-VZV-gE cell culture supernatant,attenuated live varicella vaccine and attenuated live herpes zoster vaccine,the A_(450)of other samples were all less than 0.15 with no cross reaction.The content of gE in the supernatant of three batches CHO-VZV-gE cells increased gradually with the culture time,and was positively related with culture time within 14 days(R2value was 0.999.The recoveries of accuracy verification were 94.9%~114.0%;The coefficients of variation(CVs)of precision verification were all less than 15%.Except CHO-VZV-gE cell culture supernatant,attenuated live varicella vaccine and attenuated live herpes zoster vaccine,the A_(450)of other samples were all less than 0.15 with no cross reaction.The content of gE in the supernatant of three batches CHO-VZV-gE cells increased gradually with the culture time,and was positively related with culture time within 14 days(R2=0.995 6,P=0.000 1).ConclusionThe developed double antibody sandwich ELISA had good accuracy,precision and specificity,which might be used for rapid detection of gE antigen content in VZV vaccine.
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【Objective】 To establish an enzyme-linked immunosorbent assay (ELISA) method for the determination of residual human coagulation factor Ⅺ in human prothrombin complex and validate the method. 【Methods】 Human factor Ⅺ was reacted with the capture antibody coated on the microtiter plate. After appropriate washing steps, biotinylated primary antibody was bound to the captured protein. Excess primary antibody was washed away and bound antibody was reacted with horseradish peroxidase conjugated streptavidin. TMB substrate was used for color development at 450 nm. The dilution reliability, accuracy, specificity, repeatability, intermediate precision, linearity, range and durability were verified. 【Results】 The verification results showed that the accuracy and specificity of this method met the experimental requirements, with an average recovery rate of 109.2% and RSD of 6.93%. The repeatability RSD was 6.78%, and the intermediate precision RSD was 6.75%, indicating good precision. The linear regression correlation coefficient of standard curve was 0.999 9, showing good accuracy and precision within the linear range. The durability was verified by the incubation time and the validity period of reagent kit opening. The results showed that the RSD of the incubation time change was 6.62%, indicating that the incubation time of this detection method was controlled between 28 to 32 minutes, and there was no significant impact on the results. The RSD of the detection results before and after the reagent kit was opened and stored under conditions for 7 days was 3.84%, indicating that the preservation of the reagent kit according to the conditions for 7 days after opening has no effect on the FⅪ detection results. Both indicated that the method had good durability. The dilution reliability results showed that there was a "hook" effect in the detection of FⅪ residue in human prothrombin complex, which could be solved by diluting 100 to 200 times. 【Conclusion】 This method can be used for the determination of FⅪ residues of human prothrombin complex in laboratory.
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【Objective】 To evaluate the effectiveness of random quality control sampling in blood sample detetion by ELISA. 【Methods】 Blood samples of 5 mL specification of blood donors from our blood station from May to July 2022 were selected for routine operation on a fully automated sampler. J standard substances(3 mL specification) as daily samples were added to A1 well, H12 well and random wells of HBsAg, anti-HCV, anti-HIV, and -TP, and then placed in a fully automated enzyme immunoassay analyzer for testing. With random well quality control as the internal quality control judgment standard, 20 consecutive tests were conducted and were divided into A1 (well) group, H12 (well) group and random (well) group according to different well positions. Quality control maps were drawn using Levey-Jennings quality control chart with random group as the framework, and were compared with the quality control map of A1 well and H12 well results in the same day. 【Results】 The mean quality control levels of infectious indicators of blood transfusion in blood donors by ELISA were: HBsAg 3.87±0.28, anti-HCV 3.79±0.38, anti-HIV 3.64±0.30 and anti-TP 4.53±0.51. 【Comparison】 of HBsAg, anti-HCV, anti-HIV and anti-TP, between random group, A1 group and H12 group were HBsAg 3.87± 0.28 vs 4.09±0.30 vs 3.64±0.26, anti-HCV 3.78±0.37 vs 3.96±0.38 vs 3.63±0.38, anti-HIV 3.63±0.31 vs 3.82±0.32 vs 3.48±0.28 and anti-TP 4.51±0.51 vs 4.71±0.52 vs 4.36±0.51, The S/CO value of each indicator were H12 group<random group<Al group (P<0.05), and the mean quality control levels of random group were similar to each detection indicator (P>0.05) . Using random group as the quality control framework standard, 5 points in group A1 fell outside of +2s, and 1 point in group H12 fell outside of -2s, resulting in a total of 6 alarms. With the quality control substance placed in A1 well of the ELISA plate, the judgment of detection results of the entire ELISA plate could be inevitably affected, especially the last row of low concentration virus marker samples on the ELISA plate. 【Conclusion】 The application of random quality control sampling method in donor blood by ELISA is scientific and reasonable, which can reduce the systematic error caused by artificial setting of ELISA plate fixed well positions and can also discover edge effects that affect the detection results.
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@#Objective To compare three methods for detection of antibody level in serum immunized with SARS-CoV-2mRNA vaccine. Methods Enzyme-linked immunosorbent assay(ELISA),pseudo virus-based neutralization assay(PBNA)and micro-cytopathic effect neutralization test(MCPENT)were used to detect the antibody levels of a total of 120 serum samples(40 before immunization and 80 after immunization)before and after 2 doses of mRNA vaccine immunization,and the consistency and correlation of the three methods were analyzed. Results The consistency rates of the three methods detecting 120 serum samples were all over 90%,the Kappa coefficients were all more than 0. 7,and each P was less than0. 01. The correlation coefficient(r)between the antibody potency results of positive serum samples detected by the three methods was 0. 825~0. 902,and each P was less than 0. 01. Conclusion The three methods have good consistency and correlation in detecting antibody level of serum immunized with SARS-CoV-2 mRNA vaccine.
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Zearalenone(ZEN) is a toxic metabolite produced by Fusarium culmorum, F. graminearum, F. tricinctum, and other fungi, with estrogenic characteristics. Exposure to or ingestion of ZEN during pregnancy can cause reproductive dysfunction, miscarriage, stillbirth, and malformation, and seriously endanger human life and health. The detection methods for ZEN in the Chinese Pharmacopoeia(2020 edition) are liquid chromatography(LC) and liquid chromatography-mass spectrometry(LC-MS), and it is stipulated that ZEN should not exceed 500 μg in 1 000 g of Coicis Semen. Although these detection methods by instruments can achieve the qualitative and quantitative analysis of ZEN in Coicis Semen, their high detection cost and long periods hinder the rapid screening of a large number of samples in the field. In this study, the synthesized ZEN hapten was conjugated with bovine serum albumin(BSA) and ovalbumin(OVA) to obtain the complete ZEN antigen. By virtue of antibody preparation techniques, ZEN monoclonal antibody 4F6 was prepared, which showed 177.5%, 137.1%, and 109.7% cross-reactivity with ZEN structural analogs zearalanol, zearalenone, and α-zearalenol, respectively, and no cross-reactivity with other fungal toxins such as aflatoxin. Direct competitive enzyme-linked immunosorbent assay(dcELISA) based on ZEN monoclonal antibody 4F6 was developed for the determination of ZEN in Coicis Semen with an IC_(50) of 1.3 μg·L~(-1) and a detection range of 0.22-21.92 μg·L~(-1). The recoveries were 83.91%-105.3% and the RSD was 4.4%-8.0%. The established dcELISA method was used to determine the ZEN residuals in nine batches of Coicis Semen samples, and the results were validated by LC-MS. The correlation between the two detection methods was found to be 0.993 9, indicating that the established dcELISA could be used for the rapid qualitative and quantitative detection of ZEN residuals in Coicis Semen.
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Humans , Female , Pregnancy , Zearalenone , Coix , Enzyme-Linked Immunosorbent Assay , Mycotoxins , Antibodies, MonoclonalABSTRACT
Objective:To grasp the distribution of fine antigenic epitope profiles of nucleoprotein (NP) and glycoprotein (GP) fragments of Crimean-Congo hemorrhagic fever virus (CCHFV) and to clarify the value of dominant antigenic epitopes in laboratory testing of Crimean-Congo hemorrhagic fever (CCHF).Methods:In a minimal synthetic short peptide consisting of 8 amino acids was segmentally expressed by CCHFV YL04057 strain using a modified bio-peptide synthesis method from 2014 to 2021 in the laboratory of Xinjiang University, College of Life Sciences. Using CCHFV polyclonal antibody or monoclonal antibody 14B7 (IgM) or CCHFV-positive sheep serum as antibodies, the minimal antigenic epitopes (BCEs) with antigenic activity on NP and GP fragments were identified by immunoblotting, and the obtained BCEs with sequence polymorphism were spatially clustered with CCHFV from different regions using the neighbor-joining method to determine the combination mode of BCEs with geographical correlation of regional distribution, to explore its application in establishing serological diagnosis. A prokaryotic expression plasmid (pET-32a), an E. coli expression plasmid (pGEX-KG) and a prokaryotic expression plasmid with an incomplete glutathione (GST188) tag (pXXGST-ST-1) were used to construct and express six dominant antigenic epitopes of different peptide lengths on NP fragments, and an indirect Enzyme-linked immunosorbent assay (ELISA) was established. CCHF sheep serum identified by immunofluorescence assay (IFA) was used as a control, and the specificity, sensitivity and overall compliance of the recombinant proteins with different peptide lengths of antigenic epitopes with IFA assay results were statistically analyzed. Results:CCHFV, NP and GP fragments had a total of 30 antigenically active BCEs, among which the core intermediate fragment NP2 (aa 170 th-305 th), which had a concentration of antigenic epitopes in the NP fragment, has 6 BCEs, and the NP1 (aa 1 st-200 th) and NP3 (aa 286 th-482 nd) at both ends have 9 BCEs; the Gc (aa 1 st-558 th) and Gn (aa 533 th-708 th) fragments of the GP fragment have 14 BCEs and a long antigenic peptide (AP) containing 15 amino acids, and the amino acid sequence homology of the NP fragment BCEs was 97.1% and that of the GP fragment BCEs was 89.1%. There was a significant difference ( P=0.0281, P<0.05). Among the 9 BCEs with sequence polymorphism in the GP fragment, 6 combined BCEs from GnEc1, GnE2, GnE4, GcE3, GcE6 and GcAP-4 (Ap) could cluster 15 CCHFV strains from different regions of the world into 5 geographical taxa, AsiaⅠ, AsiaⅡ, AficaⅠ, AficaⅡ and Europe. The constructs expressing PET-32a-NP (full length), PGEX-KG-NP2 (aa 170 th-305 th), pGEX-KG-NP2-1 (aa 235 th-275 th), PGEX-KG-NP2-1-1 (aa 237 th-256 th), pXXGST-1-NP2-1-2 (aa 250 th-265 th) and PGEX KG-NP2-1-3 (aa 260 th-276 th), six recombinant proteins CCHFV NP rabbit polyclonal antiserum (pAb) Western Blotting reaction positive, 33 sheep sera tested by IFA XHF as a reference, the sensitivity of the assay established by indirect ELISA using the recombinant proteins constructed from two fragments of NP2 and NP2-1 as antigens. The sensitivity, specificity and overall compliance were the best, with 73.4% (11/15) and 66.7% (10/15) for sensitivity, 100% (18/18) and 94.4% (17/18) for specificity, and 87.9% (29/33) and 81.8% (27/33) for overall compliance. Conclusion:CCHFV NP and GP are distributed with a high number of BCEs with antigenic immunoreactivity, among which the dominant antigenic epitopes are of high value in the laboratory serological diagnosis of CCHF.
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@#Objective To prepare the second generation internal control reference(B2)for Ig G antibody against severe acute respiratory symptom coronavirus 2(SARS-CoV-2)and evaluate its applicability in ELISA detection method. Methods Among the volunteers vaccinated with SARS-CoV-2 inactivated vaccine(BBIBP-Cor V)produced by Beijing Institute of Biological Products Co.,Ltd.,19 Ig G antibody positive plasma samples with ELISA-Ig G dilution ratio of 20 ~ 60 were screened,and the Ig G antibody,IgM antibody and neutralizing antibody were detected by ELISA,B2 was prepared from nonlipid plasma with ELISA-Ig G dilution ratio of 32 ~ 45,IgM negative and similar neutralizing antibody inhibition rate. The neutralizing antibody potency of the first generation internal control reference(B1)and B2 detected by ELISA was calibrated with the first generation WHO international standard of anti-SARS-CoV-2 immunoglobulin(NIBSC 20/136),and the accelerated stability(storage at 2 ~ 8 ℃ for 5,8,14,20,and 30 d respectively),the service stability(storage at 18 ~25 ℃ for 1,2,and 3 h respectively),the freeze-thaw stability(1,2 and 3 times)and the long-term stability(storage at-25 ℃ for10 months)of B2 were tested. B2 was used as standard to detect plasma after single vaccine immunization and mixed plasma was prepared according to different ELISA-Ig G dilution ratio. The correlation and linear regression analysis between ELISA-Ig G dilution ratio and neutralizing antibody potency of pseudovirus in mixed plasma were carried out. Results Among 19 plasma samples,5 samples were non-lipid plasma with ELISA-Ig G dilution ratio of 32 ~ 45,IgM negative and similar neutralizing antibody inhibition rate. B2 was prepared by mixing every plasma in equal volume fraction,and the dilution ratio of ELISA-Ig G was assigned to 32. The neutralizing antibody potency of B1 calibrated with NIBSC 20/136 was 133. 38 EIU/m L and that of B2 was 122. 14 EIU/m L. The recovery rates of accelerated stability,service stability,freeze-thaw stability and long-term stability of B2 were all in the range of(100 ± 15)%. The ELISA-Ig G dilution ratio of the mixed plasma from the same source was significantly correlated with the neutralizing antibody potency of pseudovirus.(each R~2> 0. 99,each P < 0. 000 1).Conclusion B2 prepared from plasma immunized with SARS-CoV-2 inactivated vaccine can replace B1 prepared from plasma of COVID-19 convalescent patients.