Comparison of Two Enzyme Immunoassays and Four Lysate Antigens for the Detection of Antibody in Canine Blastomycosis

Blastomycosis, the systemic fungal disease of humans and animals caused by Blastomyces dermatitidis and the cryptic species Blastomyces gilchristii, is often misdiagnosed as a bacterial or viral pulmonary disease. Therefore, the development of improved immunodiagnostic assays for this disease has been the primary focus of research in our laboratory. The present study was designed to evaluate four Blastomyces yeast-phase lysate antigenic preparations (human, 597, Eagle River, WI;dog, ERC-2, WI;Human, B5927, Mountain Iron, MN;soil, 85, Georgia, ATCC 56920) for their ability to detect antibody in 48 serum specimens from dogs with diagnosed blastomycosis using an indirect ELISA (STD) compared to a biotin-streptavidin ELISA (B-SA). All four lysate antigens were able to detect antibodies in the specimens with mean absorbance values ranging from 0.930 (B5927) to 1.142 (ERC-2) with the STD ELSA and from 1.395 (B5927) to 1.775 (85) with the B-SA ELISA. The results indicated that both ELISA methods could be utilized for antibody detection, but the B-SA ELISA exhibited greater sensitivity than the STD ELISA with all four of the lysates.

GENE ENGINEERING EB VIRUS MEMBRANE ANTIGEN IN DETECTION OF MA-IgA ANTIBODY(COMPARISON WITH VCA-IgA AND EA-IgA ANTIBODIES)

With gene engineering EB virus membrane antigen as the diagnostic antigen, indirect immunofluo-rescence (IF) assay was used to detect IgA antibody against EB virus membrane antigen (MA-IgA) in sera from 202 nasopharyngeal carcinoma (NPC) patients and 315 controls (normal and patients with other tumors). MA-IgA antibody was positive in 96.8% of the pretreatment NPC patients with a GMT of 1:36.3. MA-IgA detection by this method was more sensitive than EA-IgA detection by IE. In contrast, patients with tumors other than NPC were negative for MA-IgA antibody. 9.1% of VCA-IgA positive persons were MA-IgA positive with a GMT of less than 1:5. No MA-IgA positive was found in VCA-IgA negatives. The results indicated that this method was relatively specific. In the treatment group, the positive rate and GMT of MA-IgA antibody declined with increase in survival time and the decline was faster than VCA-IgA. When recurrence or distant metastasis developed, similar to VCA-IgA and EA-IgA antibodies, the positive rate and GMT of MA-IgA antibody increased to its pretreatment level. Therefore, MA-IgA detection might be valuable in the early diagnosis and monitor of NPC.

Development and Validation of a Recombinant Envelop Glycoprotein Based Indirect Enzyme-Linked Immunosorbent Assay to Detect the Antibody to REV

Based on the antigenic analysis of Reticuloendotheliosis virus （REV） envelop glycoprotein （env） protein, an alternative indirect enzyme-linked immunosorbent assay （ELISA） for detection of REV antibody was developed using a truncated env protein of REV produced in Escherichia coli. This assay was validated by comparison with an indirect immunofluorescence assay （IFA） and a REV-based ELISA. The diagnostic sensitivity （DSN）, specificity （DSP） and accuracy of the env indirect-ELISA （ienv-ELISA） were 93.7, 93.3 and 93.6% compared with IFA on 1 380 field serum samples, and 84.8, 95.2 and 91.7% compared with the REV-based ELISA on 96 field sera, respectively. Cross-reactivity assay showed that this assay was REV-specific. Repeatability test revealed that the coefficients of variation of positive sera within and between runs were less than 15%. This method is simpler to produce and perform, time-saving and suitable for large scale survey of REV antibody at low cost.

Clinical significance of the detection of Rh blood group antigens and irregular antibodies in pregnant women with a second pregnancy

Objective:To investigate the phenotype distribution of five antigens of Rh blood group system and the specificity of Rh blood group irregular antibodies in pregnant women with second child.To analyze the relationship between Rh blood group antibody and hemolytic disease of the newborn(HDN)in second-child pregnant women,and to provide laboratory basis for the diagnosis and treatment of hemolytic disease of the newborn(Rh-HDN).Methods:500 pregnant women with second child were collected as the study group and 500 pregnant women with first pregnancy as the control group(all pregnant women underwent obstetric examination in the integrated obsteric clinic of our hospital from January 2020 to January 2021).To detectethe Rh blood group antigens(D,C,c,E,e)of the two groups of samples,screene the irregular antibodies,identify the specificity of irregular antibodies,determine the titer and record the hemolytic disease of the newborn of pregnant women with positive Rh blood group antibodies.Results:There were 11 Rh phenotypes in the pregnant women with second child in the study group:CCDee(152cases,30.4%),CcDEe(136cases,27.2%)CcDee(84cases,16.8%),ccDEE(30cases,6%),ccDee(31cases,6.2%),CCDEe(14cases,2.8%),ccDEe(9cases,1.8%),cc dee(18cases,3.6%),CCDEE(2cases,0.4%),CcdEe(12cases,2.4%),Ccdee(6cases,1.2%),CCd ee(6cases,1.2%).A total of 42 cases(8.4%)in the pregnant women with second child were negative for RhD.There were 10 Rh phenotypes in the pregnant women with first pregnancy in the control group:CCDee(144cases,28.8%),CcDEe(138cases,27.6%),CcDee(90cases,18%),ccDEE(42cases,8.4%),ccDee(28cases,5.6%),CCDEe(10cases,2%),ccDEe(8cases,1.6%),cc dee(19cases,3.8%),CCDEE(1cases,0.2%),CcdEe(11cases,2.2%),Ccdee(9cases,1.8%).A total of 39 cases(7.8%)in the pregnant women with first pregnancy were negative for RhD.In the pregnant women with second child in the study group,the positive rate of irregular antibody screening was 4.0%(20/500),and the specificity of Rh blood group antibodies was found as follows:anti-E 1.8%(9/500),anti-D 1.4%(7/500),anti-C 0.4%(2/500)and anti-Ec 0.4%(2/500).The positive rate of irregular antibody screening in the pregnant women with first pregnancy in the control group was 0,and the difference between the two groups was statistically significant(P<0.05).Rh-HDN was found in 10 newborns(2%)of the 20 women with positive irregular antibodies in the pregnant women with second child,and the antibody titer during pregnancy was more than 32.No Rh-HDN occurred in newborns in the pregnant women with first pregnancy,and the difference between the two groups was statistically significant(P<0.05).Conclusion:Pregnancy stimulation can increase the probability of irregular antibodies in pregnant women,and irregular antibodies in Rh blood group can easily cause Rh-HDN,so attention should be paid to routine detection of five antigens of Rh blood group and irregular antibody screening during prenatal examination.It is helpful for the early detection of Rh-blood irregular antibodies and the assessment of fetal or neonatal risk of Rh-HDN.

DETECTION OF CANCER-ASSOCIATED ANTIGEN IN FECES USING MONOCLONAL ANTIBODIES IN THE DIAGNOSIS OF COLON CARCINOMA

Monoclonal antibodies against colon and pancreatic cancer, CL-2, CL-3, PS-9, PS-10, were used to detect the associated antigens in feces of patients with gastrointestinal carcinoma and non-cancer diseases. Binding inhibition test by SABC-ELISA method were performed for the measurement of the antigen level. Results showed that the associated antigen detected in feces of patients with colon cancer were significantly higher than that of non-cancer disease or normal subjects. The positive rates were 61.1% as detected with CL-2; 53.4% with CL-3; 55.0%, PS-9; and 53.3% PS-10 in cancer patients while that in normal subjects were 7%; 9%; 8%; and 8% respectively. When 'cocktail' of CL-2, PS-9 and PS-10 were used, the positive rates were 92.5% in colon cancer and 14% in normal subjects. In seven out of the sixty patients with colon cancer studied who were graded as Dukes A, the results were all positive. The results seem superior to the serologic detection and may provide a promising new approach in the early diagnosis of colon cancer.

Rapid and sensitive detection of Epstein-Barr virus antibodies in nasopharyngeal carcinoma by chemiluminescence strips based on iron-porphyrin single atom nanozyme

The correlation between Epstein-Barr virus(EBV)infection and nasopharyngeal carcinoma(NPC)risk has been extensively researched.The continual monitoring of EBV-IgAs provides a promising approach of NPC screening in its early stage.In this study,we successfully synthesized a single-atom nanozyme(SANzyme)through the application of iron-porphyrin based metal organic framework(MOF-FeP).The MOF-FeP possesses precisely-defined electronic and geometric structures that accurately mimic highly-evolved catalytic site of natural peroxidase.The peroxidase-like activity of MOF-FeP enables it to catalyze the chemiluminescence of luminol substrate.By integrating MOF-FeP into a traditional strip,we created a rapid and highly-sensitive evaluation tool for detecting EBV-IgAs.Importantly,the MOF-FeP strip enables the simultaneous detection of three EBV-IgAs,greatly improving the accuracy of EBV-associated NPC screening.The sensitivities of the MOF-FeP strip(75.56%–93.30%)surpass those of current enzyme-linked immunosorbent assay(ELISA)methods(64.44%–82.22%).This test takes only 16 min to perform as opposed to the customary 1–2 h required for standard ELISA.Additionally,the MOF-FeP strip is suitable for whole blood samples,thereby significantly simplifying the sample preparation and detection process.In conclusion,the MOF-FeP strip combines the simplicity of traditional strip with the high catalytic activity of SANzyme.Our innovative MOF-FeP strip offers a new point-of-care strategy for EBV-IgAs detection,which is expected to markedly facilitate early screening for EBV-associated diseases.

Suspected SARS-CoV-2 infection with fever and coronary heart disease:A case report

BACKGROUND The coronavirus disease 2019(COVID-19)is an emerging infectious disease caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).Suspected cases accounted for a large proportion in the early stage of the COVID-19 outbreak.The deviation of the nucleic acid test by throat swab(the current gold standard of COVID-19)caused by variation in sampling techniques and reagent kits and coupled with nonspecific clinical manifestations make confirmation of the suspected cases difficult.Proper management of the suspected cases of COVID-19 is crucial for disease control.CASE SUMMARY A 65-year-old male presented with fever,lymphopenia,and chest computed tomography(CT)images similar to COVID-19 after percutaneous coronary intervention.The patient was diagnosed as having bacterial pneumonia with cardiogenic pulmonary edema instead of COVID-19.This was based on four negative results for throat swab detection of SARS-CoV-2 nucleic acid using reverse transcriptase-polymerase chain reaction assay and one negative result for serological antibody of SARS-CoV-2 with the serological assay.Additionally,the distribution of ground-glass opacities and thickened blood vessels from the CT images differed from COVID-19 features,which further supported the exclusion of COVID-19.CONCLUSION Distinguishing COVID-19 patients from those with bacterial pneumonia with cardiogenic pulmonary edema can be difficult.Therefore,it requires serious identification.

Detection of Islet Cell Antibodies by Using Avidin-Biotin-Peroxidase Complex Technique

Autoimmunemechanisms may be involved in the pathogenesis of insulin dependent diabetes mellitus (IDDM).Multiple autoantibodies have been detected in patients with IDDM.Islet cell antibodies(ICA) complment-fixing islet cell antibodies(CF-ICA) and antibodies to an islet cell protein