OBJECTIVE: To establish a new method for synthesizing Lewis blood group antigens, that is, the mimotopes of Lewis blood group antigens were screened by using an alpaca phage display nanobody library. METHODS: We selected mimotopes of the Lewis a (le^a) antigen by affinity panning of an alpaca phage display nanobody library using a monoclonal anti-le^a antibody. Enzyme-linked immunosorbent assay (ELISA) was used to test the affinity of the positive clones for the monoclonal anti-le^a antibody, and the high-affinity positive clones were selected for sequencing and synthesis. Finally, the sensitivity, specificity and reactivity of the synthesized le^a mimotope in clinical samples were verified by ELISA. RESULTS: A total of 96 phage clones were randomly selected, and 24 were positive. Fourteen positive clones with the highest affinity were selected for sequencing. The result showed that there were 5 different sequences, among which 3 sequences with the highest frequency, largest difference and highest affinity were selected for expression and synthesis. The sensitivity and specificity of le^a mimic antigen by ELISA showed that, the minimum detection limit of gel microcolumn assay (GMA) and ELISA method were 25 times different, and the le^a mimic antigen had no cross reacted with the other five unrelated monoclonal antibodies(P<0.001). Finally, 30 clinical plasma samples were analyzed. The mean absorbance of the 15 positive plasma samples was significantly higher than that of the 15 negative plasma samples (P=0.02). However, the positive signal values of the clinical samples were much lower than those of the monoclonal antibodies. CONCLUSION A new method of screening le^a mimic antigen by using alpaca phage nanoantibody library has been established, which is expected to realize the screening of le^a mimotopes, thus realizing the application of high-sensitivity detection methods such as ELISA and chemiluminescence in blood group antibody identification.
Animals ; Antibodies, Monoclonal ; Antineoplastic Agents, Immunological ; Bacteriophages ; Blood Group Antigens ; Camelids, New World ; Enzyme-Linked Immunosorbent Assay/methods* ; Epitopes ; Humans ; Lewis Blood Group Antigens ; Peptide Library

Puerarin was conjugated with bovine serum albumin(BSA) and ovalbumin(OVA) by periodate oxidation to serve as the immunogen and coating antigen, respectively. BALB/c mice were immunized with puerarin-BSA according to the routine immunization procedure, and the titer and specificity of serum were detected after three immunization. After booster immunization, mouse spleen lymphocytes were fused with mouse myeloma cells, and 24 hybridoma cell lines of the monoclonal antibodies against puerarin were screened by monoclonal antibody screening technique. Ascites was prepared and purified. The cross-reactivity of monoclonal antibody(mAb) M1 with 4'-methoxy puerarin, daidzin, puerarin-6″-O-xyloside, daidzein, mirificin, 3'-methoxy puerarin, and 3'-hydroxy puerarin was 239.84%, 112.18%, 67.89%, 58.28%, 22.37%, 0.40%, and 0.20%, respectively, and those with other analogs such as baicalein and baicalin were all less than 0.10%. The IC_(50) and the working range of the indirect competitive enzyme-linked immunosorbent assay(icELISA) for puerarin were 44.80 ng·mL~(-1) and 8.20-292.30 ng·mL~(-1), respectively. The average recovery was 91.95%-98.20% with an RSD in the range of 0.70%-2.60%. The content of puerarin in different Puerariae Lobatae Radix samples was determined with icELISA and validated by UPLC-MS. The correlation between data obtained from icELISA and UPLC-MS was 0.999 0, indicating that icELISA is suitable for the rapid detection of puerarin in Puerariae Lobatae Radix samples.
Animals ; Antibodies, Monoclonal ; Chromatography, Liquid ; Enzyme-Linked Immunosorbent Assay/methods* ; Hybridomas/metabolism* ; Isoflavones ; Mice ; Mice, Inbred BALB C ; Tandem Mass Spectrometry

To explore the clinical diagnostic efficacy of antineutrophil cytoplasmic antibody associated vasculitis (AAV) by comparing the consistency and coincidence rate of serum anti-myeloperoxidase (MPO) antibody and anti-protease 3 (PR3) antibody detected by digital liquid chip method (DLCM) and enzyme-linked immunosorbent assay (ELISA). To provide reference for the selection of detection methods of anti-MPO antibody and anti-PR3 antibody in clinical laboratory. This study is a cross-sectional study, a total of 307 cases of antineutrophil cytoplasmic antibodies were detected in the Department of Clinical Immunology, West China Hospital of Sichuan University from January to March 2021. The serum samples and related clinical information were collected. At the same time, the levels of anti-MPO antibody and anti-PR3 antibody in serum samples were detected by ELISA and DLCM, indirect immunofluorescence (IIF) was used to re-test the differential samples between the two methods. SPSS 26.0 was used to analyze the test results, Cohen's kappa coefficient analysis was used to compare the consistency of the two methods, and paired chi-square test was used to compare the sensitivity and specificity of the two methods to AAV. The results showed that the positive cases of anti-MPO antibody detected by ELISA and DLCM were 63 and 44, and the negative cases were 244 and 263; the positive cases of anti-PR3 antibody detected by ELISA and DLCM were 34 and 28, and the negative cases were 273 and 279. The results of anti-MPO antibody and anti-PR3 antibody detected by the two methods had good consistency and coincidence rate, in which the total coincidence rate of anti-MPO antibody was 92.51%, the positive coincidence rate was 66.67%, and the negative coincidence rate was 99.18%. The results of consistency analysis showed that kappa=0.741 had well consistency. The total coincidence rate of anti-PR3 antibody is 96.74%, the positive coincidence rate is 76.47%, and the negative coincidence rate is 99.27%. The consistency analysis results show that kappa=0.821 had strong consistency. The results of IIF re-test of differential samples showed that the coincidence rate between DLCM and IIF was higher. The results of comparative analysis of anti-MPO antibody and anti-PR3 antibody showed that the specificity of DLCM was better than that of ELISA, and its sensitivity was lower than that of ELISA. In conclusion, the results of anti-MPO antibody and anti-PR3 antibody detected by DLCM were consistent with those of ELISA. In the combined detection of anti-MPO antibody and anti-PR3 antibody, the specificity of DLCM is better than that of ELISA.
Humans ; Antibodies, Antineutrophil Cytoplasmic/analysis* ; Myeloblastin ; Cross-Sectional Studies ; Sensitivity and Specificity ; Fluorescent Antibody Technique, Indirect ; Enzyme-Linked Immunosorbent Assay/methods*

OBJECTIVE: To prepare monoclonal antibody against cotinine (COT) and to establish immunoassay for detecting COT in human urinary samples. METHODS: BALB/c mice were immunized with synthesized cotinine-bovine serum albumin (COT-BSA) to screen monoclonal antibody with technique of cell fusion. The monoclonal antibody was used for the indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and colloidal gold immunochromatographic strip assay for the detection of COT in human urine. RESULTS: The monoclonal antibody against COT was identified by ic-ELISA with a 50%inhibitive concentration (IC CONCLUSIONS The ic-ELISA and colloidal gold immunochromatographic strip assay using the prepared monoclonal antibody against COT have been proved to be reliable for the rapid detection of COT in human urines, which may be used for monitoring of environmental tobacco smoke.
Animals ; Antibodies, Monoclonal ; Cotinine/urine* ; Enzyme-Linked Immunosorbent Assay ; Gold Colloid ; Humans ; Mice ; Mice, Inbred BALB C ; Urinalysis/methods*

Pepino mosaic virus (PepMV) causes severe disease in tomato and other Solanaceous crops around globe. To effectively study and manage this viral disease, researchers need new, sensitive, and high-throughput approaches for viral detection. In this study, we purified PepMV particles from the infected Nicotiana benthamiana plants and used virions to immunize BALB/c mice to prepare hybridomas secreting anti-PepMV monoclonal antibodies (mAbs). A panel of highly specific and sensitive murine mAbs (15B2, 8H6, 23D11, 20D9, 3A6, and 8E3) could be produced through cell fusion, antibody selection, and cell cloning. Using the mAbs as the detection antibodies, we established double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), Dot-ELISA, and Tissue print-ELISA for detecting PepMV infection in tomato plants. Resulting data on sensitivity analysis assays showed that both DAS-ELISA and Dot-ELISA can efficiently monitor the virus in PepMV-infected tissue crude extracts when diluted at 1:1 310 720 and 1:20 480 (weight/volume ratio (w/v), g/mL), respectively. Among the three methods developed, the Tissue print-ELISA was found to be the most practical detection technique. Survey results from field samples by the established serological approaches were verified by reverse transcription polymerase chain reaction (RT-PCR) and DNA sequencing, demonstrating all three serological methods are reliable and effective for monitoring PepMV. Anti-PepMV mAbs and the newly developed DAS-ELISA, Dot-ELISA, and Tissue print-ELISA can benefit PepMV detection and field epidemiological study, and management of this viral disease, which is already widespread in tomato plants in Yunnan Province of China.
Animals ; Antibodies, Monoclonal/immunology* ; China ; Cloning, Molecular ; Enzyme-Linked Immunosorbent Assay/methods* ; Female ; Hybridomas ; Solanum lycopersicum/virology* ; Mice ; Mice, Inbred BALB C ; Plant Diseases/virology* ; Potexvirus/metabolism* ; Sensitivity and Specificity ; Nicotiana

BACKGROUND: As stated in ‘The Action Strategy for Tuberculosis-Free Korea,’ last March, high-throughput, large-scale analytical instruments for interferon gamma release assays (IGRA) are demanded by many clinical laboratories using the QuantiFERON-TB Gold In-Tube assay (Cellestis/Qiagen, Australia). Agility (Dynex Technologies, USA) is an automated high-throughput enzyme linked immunosorbent assay analyser. The present study aimed to evaluate its accuracy and speed. METHODS: Pooled plasma was prepared using samples obtained after IGRA testing. Analyses of precision, linearity, cut-off evaluation, and comparison with conventional methods were performed for multiple Agility instruments according to the Clinical and Laboratory Standards Institute EP5-A3, EP6-A, EP9-A3 and EP12-A2 guidelines. The turnaround time and throughput were also analysed. RESULTS: The coefficient of variation range was 2.48%–4.0%, 7.01%–11.17%, and 9.69%–14.84% for the repeatability, between-run precision, and between-day precision analyses, respectively. The linearity ranged from 0 to 10.541. Comparison analysis presented a high concordance of Agility with the conventional instrument, DS2 (Dynex Technologies), and manual method for IGRA. The cut-off value of 0.35 IU/mL was well compatible with the C50. It was identified that the C50±20% contained the C5–C95 interval. The average turnaround time was 3.84 hours, from the submission of pre-treated samples to the reporting of results. The throughput was determined to be 290 tests during a routine working time of 8 hours. CONCLUSIONS: Agility showed high precision, linearity, concordance, and had a 2.5 times faster throughput than with the conventional and manual method. It could be useful for large-scale IGRA testing in latent tuberculosis infection screening project. Samples within C50±20% are suspected to show relatively low reporducible results of high inversion between postivie and negative.
Enzyme-Linked Immunosorbent Assay ; Interferon-gamma Release Tests ; Interferons ; Latent Tuberculosis ; Mass Screening ; Methods ; Plasma

Cystic echinococcosis (CE) in sheep is a hazardous zoonotic parasitic disease that is caused by Echinococcus granulosus (Eg). At present, serological test is an important diagnostic method for Eg infection in domestic animals. Here, a fusion protein Eg mefAg-1 harboring 8 dominant B-cell epitopes of Eg such as antigen B, tetraspanin 1, tetraspanin 6, reticulon and Eg95 was produced in E. coli and evaluated for CE in sheep by indirect ELISA. Eg mefAg-1 showed in ELISA a high sensitivity (93.41%) and specificity (99.31%), with a coincidence rate of 97.02%. Overall, it is suggested that the Eg mefAg-1 could be a potential antigen candidate for CE serodiagnosis in sheep.
Animals, Domestic ; Echinococcosis ; Echinococcus granulosus ; Enzyme-Linked Immunosorbent Assay ; Epitopes, B-Lymphocyte ; Methods ; Parasitic Diseases ; Sensitivity and Specificity ; Serologic Tests ; Sheep

PURPOSE: This study aimed to evaluate ichroma™ IGRA-TB, a novel point-of-care platform for assaying IFN-γ release, and to compare it with QuantiFERON-TB Gold In-Tube (QFT-GIT) for identifying Mycobacterium tuberculosis (M. tb) infection. MATERIALS AND METHODS: We recruited 60 healthy subjects, and blood samples were obtained in QFT-GIT blood collection tubes. The blood collection tubes were incubated at 37℃, and culture supernatant was harvested after 18–24 hours. IFN-γ responses were assessed by the ichroma™ IGRA-TB cartridge and the QFT-GIT IFN-γ enzyme-linked immunosorbent assay. Three active TB patients were recruited as a positive control for M. tb infection. RESULTS: The area under the receiver operating characteristic curve of the ichroma™ IGRA-TB test for differentiating between infected and non-infected individuals was 0.9706 (p < 0.001). Inconsistent positivity between the two tests was found in three participants who showed weak positive IFN-γ responses ( < 1.0 IU/mL) with QFT-GIT. However, the two tests had excellent agreement (95.2%, κ=0.91, p < 0.001), and a very strong positive correlation was observed between the IFN-γ values of both tests (r=0.91, p < 0.001). CONCLUSION: The diagnostic accuracy demonstrated in this study indicates that the ichroma™ IGRA-TB test could be used as a rapid diagnostic method for detecting latent TB infection. It may be particularly beneficial in resource-limited places that require cost-effective laboratory diagnostics.
Diagnosis ; Enzyme-Linked Immunosorbent Assay ; Feasibility Studies ; Healthy Volunteers ; Humans ; Korea ; Latent Tuberculosis ; Methods ; Mycobacterium tuberculosis ; Point-of-Care Systems ; ROC Curve ; Tuberculosis

BACKGROUND AND OBJECTIVES: Mucin is an important component of mucus that performs the first line of defense against inhaled pathogens and particles, lubrication of organs, and protection of airway. It is hyper-secreted in inflammatory airway diseases and is associated with morbidity and mortality of the affected patients. Resolvin, an autacoid of a specific lipid structure, exhibits anti-inflammatory property against inflammatory airway diseases although its effects on mucin secretion by human airway epithelial cells have not yet been demonstrated. In this regard, we investigated the effects of Resolvin on lipopolysaccharide (LPS)-induced mucin expression in human airway epithelial cells. MATERIALS AND METHOD: In mucin-producing human NCI-H292 epithelial cells, the effects and brief signaling pathways of Resolvin D1 (RvD1) and Resolvin E1 (RvE1) on the LPS-induced MUC4, MUC5AC, and MUC5B expression were investigated using reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay and Western blot analysis. RESULTS: RvD1 attenuated LPS-induced MUC4, MUC5AC, and MUC5B mRNA expression and protein production in human NCI-H292 cells while RvE1 did not. RvD1 significantly blocked LPS-induced activated phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) and p38 MAPK and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) while RvE1 did not. CONCLUSION: These results suggest that RvD1 attenuates LPS-induced MUC4, MUC5AC, and MUC5B expressions via ERK1/2 MAPK, p38 MAPK, and NF-κB signaling pathways in airway epithelial cells. Therefore, RvD1 may modulate the control of mucus-hypersecretion in inflammatory airway diseases.
B-Lymphocytes ; Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Epithelial Cells* ; Humans* ; Lubrication ; Methods ; Mortality ; Mucins* ; Mucus ; p38 Mitogen-Activated Protein Kinases ; Phosphorylation ; Phosphotransferases ; Protein Kinases ; RNA, Messenger

PURPOSE: Enzyme-linked immunosorbent assay (ELISA) has been used in the diverse field to evaluate influenza virus infection; for the surveillance, diagnosis, efficacy evaluation, and development of the vaccine. The aim of this study was to establish an ELISA for detecting HA strain-specific antibodies using recombinant pandemic A H1N1 (pH1N1) HA1 (rHA1) protein. MATERIALS AND METHODS: rHA1 was produced in baculovirus system. The clinical performance of the developed ELISA was validated using human serum samples, by comparison with standard methods for detecting a neutralizing antibody; hemagglutination inhibition (HI) assay and microneutralization test (MNT). The ability of the ELISA system to evaluate the efficacy test of an influenza vaccine was explored by measuring antibody levels in the serum of vaccinated mice. RESULTS: Our ELISA could detect anti-rHA1 antibody in influenza-infected patients and vaccinated subjects. Compared to HI assay and MNT as reference methods, our method showed good performance in detection of anti-rHA1 antibody. Detection of the anti-rHA1 antibody in vaccinated mice and its correlation with titers in HI assay was also proved in a mice model. CONCLUSION: An ELISA system using rHA1 of pH1N1 influenza virus was developed, and showed good clinical performance in diagnosis of influenza virus infection and evaluation of the vaccination efficacy in both human and animal models.
Animals ; Antibodies ; Antibodies, Neutralizing ; Baculoviridae ; Diagnosis ; Enzyme-Linked Immunosorbent Assay* ; Hemagglutination ; Humans ; Influenza A virus ; Influenza Vaccines ; Influenza, Human* ; Methods ; Mice ; Models, Animal ; Orthomyxoviridae* ; Pandemics* ; Vaccination