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Serodiagnosis of Chagas' disease using monoclonal antibody against Trypanosoma cruzi-specific Mr 25,000 antigen.

A mouse monoclonal antibody TCF87, prepared previously, was reactive with Trypanosoma cruzi-specific Mr 25,000 antigen regardless of strain. The Mr 25,000 antigen was recognized by all sera from chagasic patients living in different areas of South America, when examined by Western immunoblotting analysis. Although many antigens of T. cruzi epimastigotes were also recognized by sera from patients with leishmaniasis, the Mr 25,000 antigen of T. cruzi did not react with leishmaniasic sera. These results indicate that Mr 25,000 antigen recognized by TCF87 is valuable as a diagnostic antigen for Chagas' disease. When a competition enzyme-linked immunosorbent assay using TCF87 was carried out, all sera from Chagas' disease patients showed positive inhibition. By contrast, all patients with leishmaniasis or other parasitic diseases were scored as seronegative. The present study suggests that competition enzyme-linked immunosorbent assay using monoclonal antibody against the Mr 25,000 antigen of T. cruzi will be useful for serodiagnosis of Chagas' disease in areas where leishmaniasis is co-endemic.

Animals↗

Detection of hemorrhagic fever with renal syndrome (HFRS) virus in the lungs of bank voles Clethrionomys glareolus and redbacked voles Clethrionomys rutilus trapped in HFRS foci in the European part of U.S.S.R., and serodiagnosis of this infection in man.

The antigen of HFRS virus was demonstrated by means of the indirect fluorescent antibody procedure in the lung tissue of bank and redbacked voles (Clethrionomys glareolus, Cl. rutilus) trapped in HFRS foci in the European part of USSR. This antigen has been used satisfactorily for serodiagnosis of HFRS in several European and Asian regions of the USSR where HFRS had been found to be endemic.

Animals↗

Serodiagnosis of viral hepatitis A: rise in antibody titre and evaluation of three methods for detecting early and late antibodies.

A serological investigation was made on patients with viral hepatitis A and individuals with a past history of this disease. Titration of antibody in sequential samples was found to be of no help in diagnosis. Separation of early (IgM) from late (IgG) antibodies by protein A or by 2-mercaptoethanol did not prove to be convenient for the serodiagnosis. A chromatographic separation of late and early antibody was found to be satisfactory, and equivalent to a radioimmunoassay for IgM-antibodies.

Antibodies, Viral↗

Validation of an enzyme immunoassay for serodiagnosis of acute Q fever.

An enzyme immunoassay was validated for the serodiagnosis of acute Q fever. Minimum positive tests were determined for both serial dilutions and a single dilution of patient sera. To establish the specificity of the test, 152 serum samples were tested from individuals with no evidence of past Coxiella burnetii infection. Diagnostic titers were set at > or = 128 for the IgM and IgG responses to phase I, at > or = 512 for the IgM response to phase II and at > or = 1,024 for the IgG response to phase II Coxiella burnetii. These titers gave a false-positive rate of < or = 1%. Alternatively, testing a single dilution of sera (1:128) gave specificities ranging from 97.3 to 98.7%. Tests with the greatest sensitivities, using serially diluted early convalescent-phase sera, were the IgM (84%) and IgG (80%) responses to phase II Coxiella burnetii. At a single serum dilution, 92% of early convalescent sera had a positive IgG response to phase II Coxiella burnetii. With a high specificity and good sensitivity, the EIA can be used to diagnose acute Q fever with a single convalescent serum specimen. The duration of a positive response was greater than five years.

Coxiella burnetii↗

Simian rotavirus (SA 11) in serodiagnosis of human rotavirus infections.

Tests were made on 169 sera from children up to 10 years of age for rotavirus antibodies by indirect immunofluorescence and complement fixation tests. The simian strain SA 11 served as a substitute antigen for the human rotavirus. Furthermore, the SA 11 complement-fixing antigen was compared with a commercial antigen of the bovine rotavirus strain NCDV. It was demonstrated that SA 11 which can be more easily propagated than most bovine strains, may be used as a substitute antigen in complement fixation and indirect immunofluorescence for serodiagnosis of human rotavirus infections.

Animals↗

Serodiagnosis of cancer, using porcine antigens recognized by human monoclonal antibody, HB4C5.

Antigens, recognized by human monoclonal antibody (HB4C5) generated from a lung cancer patient, were found to occur in porcine pancreas. The antigens-I and -II were purified from crude trypsin of porcine pancreas, only by Mono Q column chromatography, and were eluted at 260 and 300 mM NaCl in 10 mM Tris-HCl buffer, pH 7.4, respectively. These antigens differed from trypsin in molecular weight, elution pattern from the Mono Q column, and their reactivity with HB4C5. The molecular weights of the two antigens were almost the same at around 35000. These were used for serodiagnosis with an assay system based on 96-well immunoplates. The reactivities of antigens-I and -II with various sera were similar. When the reactivity of IgG in serum with antigen-II was measured, absorbance at 415 nm in the case of normal and lung cancer patients was 0.178 +/- 0.056 and 0.492 +/- 0.136 (p less than 0.005). The rates of positive reaction in ovary, larynx, uterus, lung and liver cancers were more than 50%, but the rates in stomach and breast cancers were less than 30%. Positive reaction was hardly detected in pancreas cancer and normal controls.

Animals↗

Serodiagnosis of cancers by ELISA of anti-histone H2B antibody.

An enzyme-linked immunosorbent assay method for serodiagnosis of cancers was developed by employing histone H2B. This method measures anti-histone H2B antibody levels in sera and includes a device for coating the plastic immunoplate with a mixture of histone H2B and diluted fetal calf serum. The coating of immunoplates with this mixture decreased apparent sensitivity of the assay compared with that in the absence of fetal calf serum, but effective reduction of nonspecific background enabled a specific assay of anti-histone H2B antibody with excellent reproducibility. By this method cancer patients were discriminated from normal healthy subjects at detection rates of 37% for lung cancer, 33% for liver cancer, 50% for pancreatic cancer, 42% for colon cancer, and 78% for cervical cancer. However, stomach and esophagus cancers showed detection rates of less than 17%, which are comparable to the values for benign diseases. It is likely that this assay method detects squamous cell carcinomas at relatively high rates.

Antibodies, Neoplasm↗

Serodiagnosis of neuroborreliosis: comparison of reliability of three confirmatory assays.

The sensitivity and specificity of three confirmatory assays for the serodiagnosis of neuroborreliosis were investigated. Samples from 96 patients with proven neuroborreliosis, 80 healthy volunteers, 20 patients with neurosyphilis and 20 patients with recent infections with Epstein-Barr virus (EBV) were tested for borrelial antibodies by immunoblotting, Borrelia burgdorferi sensu lato sonicate EIA following pre-absorption of cross-reactive antibodies (Abs-EIA) and by a so-called RECO-EIA using the following recombinant borrelial proteins as antigens: a 14 kDa-internal flagellin fragment, the outer surface protein C (23 kDa) and the high molecular mass protein p83 (83 kDa). The immunoblots were evaluated according to the criteria published by Engström et al. and Hauser et al. An evaluation of IgM and/or IgG antibodies revealed a considerably higher sensitivity for the RECO-EIA (94%) compared to the Abs-EIA (82%, P < 0.0001). Evaluation of the immunoblot according to the criteria of Hauser was significantly more sensitive than according to the criteria of Engström (89 vs 51%, P = 0.0003). A higher sensitivity was demonstrated for IgM (54 vs 22%) and IgG antibodies (64 vs 24%). When both findings from RECO-EIA and immunoblotting were considered, positive findings in the first step assay (sonicate EIA without pre-absorption) were confirmed in 97% of patients. When samples were tested for IgM antibodies, the specificities of the three confirmatory assays did not differ significantly, but in the case of IgG antibodies, the immunoblot (Hauser: P = 0.013; Engström: P = 0.004) and the RECO-EIA (P = 0.02) were more specific than the Abs-EIA. It is concluded that the immunoblot (evaluated according to Hauser) and the RECO-EIA are both suitable as confirmatory assays in the serological diagnosis of neuroborreliosis. Monoclonal antibodies are mandatory tools in the evaluation of the immunoblot.

Absorption↗

Serodiagnosis of childhood tuberculosis by ELISA.

OBJECTIVE: Diagnosis of childhood tuberculosis remains an enigma despite many recent technological developments. The present study has been taken up with the aim to assess the diagnostic potential of mycobacterium tuberculosis excretory-secretory ES-31 antigen and affinity purified anti ES-31 antibodies in the serodiagnosis of different spectrum of childhood tuberculosis. METHODS: Mycobacterium tuberculosis H37Ra excretory-secretory antigen (ES-31) and affinity purified goat anti ES-31 antibodies were used in stick penicillinase ELISA for IgG antibody detection and stick Sandwich penicillinase ELISA for detection of circulating free and immune complexed antigen in the sera of 230 children. RESULTS: Analysis of tubercular antibody, circulating free and immune complexed antigen (CIC-Ag) was done in both pulmonary and extrapulmonary form of childhood tuberculosis and overall sensitivity of 81.4% with a specificity of 93% was achieved for detection of antitubercular IgG antibodies. Of the five cases of pulmonary tuberculosis showing absence of IgG antibody, 3 showed the presence of CIC-Ag and one was found positive for both free and CIC-Ag. Similarly out of 8 cases of extrapulmonary childhood tuberculosis missed by IgG detection 5 were found to be positive for CIC-Ag and 1 showed the positive reaction for both free and immune complexed antigens. CONCLUSION: IgG antibody to excretory-secretory antigen ES-31 is found to be having good specificity with acceptable sensitivity in detecting different forms of childhood tuberculosis. Further detection of circulating free and/or immunecomplexed antigen can be used as an adjunct tool in the diagnosis of childhood tuberculosis.

Antibodies, Bacterial↗

Serodiagnosis of subacute sclerosing panencephalitis by enzyme linked immunosorbent assay.

Thirty three young patients (23 males and 10 females), between 3-20 years of age, with a clinical suspicion of subacute sclerosing panencephalitis (SSPE) were evaluated over a period of 4 years. A past history of measles was obtained in 42.4% of the cases. One child was immunised against measles. Measles specific antibodies (IgG) were demonstrated in the cerebrospinal fluid (CSF) from 30 (90.9%) of the 33 patients by ELISA. In the remaining three cases the antibodies were detected only in the serum. Serodiagnosis of SSPE by ELISA had a sensitivity of 100%, a specificity of 93.3% and a positive predictive value of 100%.

Adolescent↗

Expression of SARS-coronavirus nucleocapsid protein in Escherichia coli and Lactococcus lactis for serodiagnosis and mucosal vaccination.

The nucleocapsid (N) protein of the severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) is an important antigen for the early diagnosis of SARS and the development of vaccines. It was expressed in Escherichia coli as a fusion with human glutathione S-transferase (hGST) and was confirmed by Western blotting analysis. This recombinant N protein (hGST-N) was purified and used to measure the SARS-CoV N-specific antibody in the sera of eight SARS patients by enzyme-linked immunosorbent assay. Specific antibody response to this purified recombinant N protein was 100% positive in the SARS patients' sera, while none of the control sera from 30 healthy people gave a positive reaction in the same assay. The SARS-CoV N protein was also expressed in Lactococcus lactis in the cytoplasm or secreted into the medium. The N-producing strain MG1363/pSECN and the purified hGST-N protein were respectively administered to mice, either orally or intranasally. Results indicated that orally delivered MG1363/pSECN induced significant N-specific IgG in the sera. In conclusion, our work provides a novel strategy to produce the SARS-CoV N protein for serodiagnosis and for L. lactis-based mucosal vaccines.

Administration, Intranasal↗

Development of enzyme-linked immunosorbent assays using recombinant borrelial antigens for serodiagnosis of Borrelia burgdorferi infection.

To improve IgG antibody detection in the serodiagnosis of Borrelia burgdorferi infection, indirect enzyme-linked immunosorbent assays (ELISAs) were developed utilizing purified recombinant antigens of B. burgdorferi sensu lato: the chromosomally encoded proteins p100 of strain PKo (B. afzelii) and p4li (internal flagellin fragments) derived from strains PKo, PBi (B. garinii), and B31 (B. burgdorferi sensu stricto). In Western blot analysis, these proteins have proved to be highly specific and sensitive for IgG antibody detection, especially in late manifestations of Lyme borreliosis. Sera from 464 forest workers, a high-risk group for infections with B. burgdorferi, were investigated and the results compared with those obtained by a commercial ELISA using an octyl-beta-D-glucopyranoside (OGP) extract from B. afzelii (PKo) cells as the antigenic substrate. Sera derived from 200 blood donors served for determination of the 95% specific cut-off level. The number of positive test results using OGP-ELISA (23.9%) was only slightly higher than that using p100-ELISA (19.8%); corresponding results were observed in 84.7% of all sera (14.2% positive, 70.5% negative). The frequency and interassay correspondence of positive results increased with the age of the forest workers, as most markedly demonstrated by p100 and OGP assays (P < 0.0001). Using the p41i-ELISAs, generally no significant strain-dependent differences in sensitivity were found (PKo, 13.8%; PBi, 14.2%; B31, 12.9%). Compared with the p100-ELISA, the p41i-assays showed significantly lower detection rates for IgG antibodies (P < 0.03) and a reduced capacity for quantitative discrimination between seropositive individuals and negative controls (P < 0.0007). At a 95% specificity, the IgG antibody detection rate could be increased to 23.1% when the p100-ELISA was evaluated in combination with the assays using p41i/PBi and P41i/B31. Due to its high sensitivity, the specific recombinant p100-ELISA might be a suitable test for detection of late immune responses to B. burgdorferi, thus being especially useful for epidemiological investigations.

Adolescent↗

Enzyme-linked immunosorbent assays with recombinant internal flagellin fragments derived from different species of Borrelia burgdorferi sensu lato for the serodiagnosis of Lyme neuroborreliosis.

The serodiagnosis of early Lyme neuroborreliosis is hampered by false negative results and one of the reasons could be the heterogeneity of strains of Borrelia burgdorferi sensu lato. For this study IgG enzyme-linked immunosorbent assays (ELISAs) with recombinant internal flagellin fragments (p41/i; amino acids 129-251) derived from strains PKo (B. afzelii), B31 (B. burgdorferi sensu stricto), and PBi (B. garinii) and ELISAs with whole-cell detergent extracts of strains PKo, PKa2 (B. burgdorferi sensu stricto), and PBi were compared. Cut off absorbance values were defined by the 94th and 92th percentiles of 200 sera from blood donors. Sera from patients with clinically defined neuroborreliosis [n = 88; 41 culture proven and 47 intentionally selected by the criteria specific IgG cerebrospinal fluid/serum index > or = 2 and a serum IgG immunofluorescence assay value of < 1:64] were tested. The sensitivities of the three whole-cell detergent-extract ELISAs were similar (46.6-49.2%), whereas those of the recombinant ELISAs were highest with p41/i:PBi (57.1%) and lowest with p41/i:PKo (21.5%). A combination of the p41/i:PBi and the p41/i:B31 test was most sensitive (59.8%). The correlation of absorbance values of different assays was very high for the three whole-cell detergent-extract ELISAs, whereas the absorbance values obtained with the three recombinant tests differed considerably. The greatest differences were observed between p41/i:PKo and any of the other two recombinant antigens. The differences in immune reactivity of patients sera (due to strain heterogeneity?) seems to have more influence on the results of an assay based on a single antigen than on a whole-cell-based test.

Antibodies, Bacterial↗

Evaluation of human IgG subclass antibodies in the serodiagnosis of angiostrongyliasis.

Immunoglobulin G subclass antibody (IgG1, IgG2, IgG3, and IgG4) responses to the rat lungworm, Angiostrongylus cantonensis, were analyzed using the immunoblotting technique in an attempt to further improve the sensitivity and specificity for the serodiagnosis of human angiostrongyliasis. Serum samples from patients with proven angiostrongyliasis and from clinically suspected cases of angiostrongyliasis with eosinophilic meningitis were tested. Sera from patients with other parasitic illnesses and from healthy volunteers were also analyzed. The results indicate that the immunoblotting used to detect IgG4 antibodies to the antigenic band of an approximate molecular mass of 29 kDa from young adult somatic extract of A. cantonensis is the most reliable test. It gives accuracy, sensitivity, specificity, and positive and negative predictive values of 89.2%, 75%, 95%, 85.7% and 90.4%, respectively. More importantly, the test can discriminate between human angiostrongyliasis, gnathostomiasis and cysticercosis, three diseases that produce eosinophilic meningitis.

Angiostrongylus cantonensis↗

Assessment of a recombinant antigen versus natural hypodermin C for the serodiagnosis of hypodermosis in cattle.

An indirect ELISA test using as antigen a recombinant parasite protein, hypodermin C, was developed to measure Hypoderma-specific antibodies in cattle sera and compared with natural hypodermin C. To evaluate the field efficacy of the ELISA test, 334 serum samples were collected from cows raised at farms in Galicia for a serological survey. Compared with an ELISA based on natural parasite antigen, the recombinant hypodermin C gave excellent results, with a sensitivity of 95.8% and a specificity of 95.7%. Considering the cut-off point, with the recombinant hypodermin C, 70.9% of the animals had positive levels of antibodies to Hypoderma and with natural hypodermin C, 73.6%. Recombinant hypodermin C appears to be a useful alternative to the natural parasite antigen for the serodiagnosis of Hypoderma sp in cattle.

Animals↗

Evaluation of a rapid immunochromatographic test for serodiagnosis of visceral leishmaniasis.

The purpose of this study was to compare the performance of a rapid immunochromatographic dipstick test for the qualitative detection of circulating antibodies to the leishmanial recombinant antigen K39 with that of a classical immunofluorescent antibody test for serodiagnosis of visceral leishmaniasis. Sera from 143 Italian subjects, including 69 patients with clinically suspected visceral leishmaniasis, 23 patients with hypergammaglobulinemia and 51 healthy controls, were tested. The immunochromatographic test was performed according to the manufacturer's instructions, using antigen-impregnated nitrocellulose paper strips. The immunofluorescent antibody test was performed according to an established method, using promastigotes of Leishmania infantum zymodeme Montpellier 1 as antigen. In 11 patients, diagnosis of active Leishmania infection was established by microscopic examination of biopsy samples and/or clinical response to meglumine antimoniate. Results of the two tests correlated for all but two sera examined. In two patients, one with proven infectious mononucleosis and one with bacterial pneumonia, the immunofluorescent antibody test was positive and the dipstick test was negative. In the restricted sample of patients in whom a definitive diagnosis was established, the immunochromatographic test was positive in 11 of 11 patients with confirmed Leishmania infection and negative in 103 of 103 subjects who either had other documented diseases or were healthy controls, showing 100% sensitivity and 100% specificity.

Animals↗

Development of immunoglobulin G enzyme-linked immunosorbent assay for the serodiagnosis of severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a novel SARS-associated coronavirus (SARS-CoV). The clinical characteristics are high fever, rapidly progressive diffuse pneumonitis and respiratory distress. It is highly infectious through intimate contact or direct contact with infectious body fluids. Outbreaks within communities and hospitals have been reported. Development of rapid and reliable diagnostic tools is urgently needed. We developed an immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), using whole virus antigen of SARS-CoV. Eighty-six serum samples collected from patients who were hospitalized for other causes were examined to determine the cut-off O.D. value. The cut-off O.D. value was defined as 0.175 by calculating the mean O.D. value of the 86 sera plus 3 standard deviations. To determine the sensitivity and specificity of the ELISA, 56 positive sera and 204 negative sera were tested. The sensitivity was 96.4% and the specificity was 100%. The results suggest that the IgG ELISA using whole virus antigen of SARS-CoV has a high sensitivity and specificity in detecting SARS IgG antibodies. This IgG ELISA is a powerful tool for serodiagnosis of SARS.

Antigens, Viral↗

The use of murine monoclonal antibodies without purification of antigen in the serodiagnosis of tuberculosis.

A serum diagnostic test for tuberculosis has been devised on the basis of competitive inhibition by human sera of the binding of 125I-labelled murine monoclonal antibodies (Mabs) to a solid-phase bound pressate of M. tuberculosis. Five monoclonal antibodies binding to distinct antigenic determinants of the organism were used as structural probes which conferred their stringent combining site specificities to the polyclonal mixture of human antibodies. Sera from patients but not from healthy controls competed effectively with the binding of 125I-labelled Mabs to M. tuberculosis-coated polyvinyl plates. This inhibition technique eliminated the need for elaborate purification of antigen used in previous serological methods. Some Mabs gave considerably more positive results than others. The best combination of tests used 2 Mabs and yielded a positive result in 71% of 41 patients with smear-positive pulmonary tuberculosis. This approach is applicable in principle to the serodiagnosis of other human bacterial diseases.

Animals↗