SERODIAGNOSIS OF CLONORCHIASIS BY ENZYME—LINKED IMMUNOSORBENT ASSAY WITH HRP—SPA

In thes paper the authors used the Horseradish peroxidase labelledstaphylococcal protein A(HRP—SPA)in ELISA,for the detection of Clo-norchis sinensis infection.Serum tests were made on 116 confirmed cases ofclonorchiasis,103(88.8%)of them showed positive,while only 6(4.4%)werepositive among 138 healthy people.Samples were collected on filter paperstrips,111(95.7%)cases were positive among 116 comfirmed cases tested,but only 2(1.5%)were positive out of 138 healthy persons.The resultswere similar to those obtained by sheep antihuman IgG.Animal experimentalso showed that the SPA—ELISA can be used for the diagnosis ofclonorchiasis.In an endemic area,stool egg positive rate was 8.8%(62/703).whenchecked with SPA—ELISA,the rate of conformity in both filter paperstrips and stool examinations was 90.3(56/62).Among 641 serum testsfrom individuals negative in stool examinations,only 35(5.5%)reactedpositively.The authors suggested—that SPA—ELISA with soluble Clo-norchis antigens could be used in a large scale seroepidemiological surveyin endemic areas.

New insights on serodiagnosis of trichinellosis during window period:early diagnostic antigens from Trichinella spiralis intestinal worms

The clinical diagnosis of trichinellosis is difficult because its clinical manifestations are nonspecific.Detection of anti-Trichinella IgG by ELISA using T.spiralis muscle larval excretory-secretory(ES)antigens is the most commonly used serological method for diagnosis of trichinellosis,but the main disadvantage is false negativity during the early stage of infection.There is an obvious window period between Trichinella infection and antibody positivity.During the intestinal stage of Trichinella infection,the ES antigens of intestinal worms(intestinal infective larvae and adults)are exposed to host’s immune system at the earliest time and elicit the production of specific anti-Trichinella antibodies.Anti-Trichinella IgG antibodies in infected mice were detectable by ELISA with ES antigens of intestinal worms as soon as 8-10 days post infection(dpi),but ELISA with muscle larval ES antigens did not permit detection of infected mice before 12 dpi.Therefore,the new early antigens from T.spiralis intestinal worms should be screened,identified and characterized for early serodiagnosis of trichinellosis.

Antigenicity of severe fever with thrombocytopenia syndrome virus nucleocapsid protein and its potential application in the virus serodiagnosis

Dear Editor,Severe fever with thrombocytopenia syndrome virus(SFTSV)is a newly identified viral pathogen of the genus Phlebovirus in the family Bunyaviridae(Sun et al.,2012).SFTSV was first identified from patient serum samples in China(Li et al.,2013;Ning et al.,2015).SFTSV can cause a severe hemorrhagic fever-like disease with a reported case fatality rate ranging from 2.5%

Construction and Expression of Tp0453 Recombinant Protein of Treponema pallidum and Development of Indirect ELISA for Diagnosinq Syphilis

Objectives： To clone and express Tp0453 outer membrane protein of Treponema pallidum, and to evaluate its significance in the serodiagnosis of syphilis. Methods： The immuno-dominant epitope of Tp0453 gene was amplified from the complete genome of T.pallidum by polymerase chain reactions （PCR）, subcloned into the expression vector Pqe32 to generate recombinant plasmid Pqe32/Tp0453, and was then expressed in E. coli M15. The fusion protein was purified with Ni-NTA affinity purification. Indirect ELISA was developed to detect human serum IgG antibody to T. pallidum. Results： The recombinant Tp0453 protein was successfully expressed and purified. The recombinant protein had a molecular weight of approximately 32KDa.Indirect ELISA to the recombinant protein was developed.Sixty control sera were tested by ELISA and yielded a sensitivity of 100% （30/30） and a specificity of 100% （30/30）. While testing for T. pallidum in human sera, the sensitivity and specificity of ELISA were 96.8% and 100%, respectively, when compared with TPPA test results. The concordance of results between the ELISA test and the TPPA test was 98.2%. Conclusion： The recombinant Tp0453 outer membrane protein elicited a strong immunoreaction to anti-T.pallidum IgG antibody and has great potential use in ELISA for the serodiagnosis of syphilis.

Helicobacter pylori infection and gastrointestina hormones:a review

INTRODUCTIONHelicobacter pylori(Hp)infection is closely relatedto gastrointestinal hormones and involves theformation of gastritis,gastric carcinoma and pepticulcer.Its pathogenesis relevant

Transfusion transmitted virus infection in general populations and patients with various liver diseases in south China

INTRODUCTIONAlthough several specific detecting methods hadbeen applied to determine the hepatitis virus,therewas a lot of cryptogenic hepatitis without anyknown hepatitis infectious marker.Theprevalence of hepatitis G virus (HGV) (also knownas GB-C virus) infection has been reported to be 5%-13% in patients with non-A-E hepatitis andcirrhosis,however,there is little evidencesuggesting that HGV causes hepatitis in human.

Detection of H pylori infection by ELISA and Western blot techniques and evaluation of anti CagA seropositivity in adult Turkish dyspeptic patients

AIM: To detect H pylori infection and to evaluate the anti CagA seropositivity in adult Turkish dyspeptic patients. METHODS: We evaluated anti-H pylori IgA, IgG and anti-CagA antibodies using commercial enzyme-linked immunoassay (ELISA) and Western blot in dyspeptic Turkish patients. H pylori status was determined by histology and rapid urease testing. RESULTS: Fifty-six patients were entered. Forty-eight (85.7%) out of the 56 patients were positive for H pylori. H pylori IgG seropositivity was 82.1%, IgA seropositivity 48.2%. CagA ELISA showed that IgG was positive in 50% and IgA in 30.4% of those with H pylori infections. Western blot showed that IgG seropositivity was 80.4% and IgA seropositivity 33.9%. Western blot detected IgG antibodies with reactivity to CagA in 50%, VacA in 62.5%, UreB in 87.5%, UreA in 80.4%, and OMP in 57.1%. None of the tests had a sensitivity and specifi city above 80%. CONCLUSION: None of these commercial tests seems clinically useful for H pylori detection in adult dyspeptic patients, while Western blot can give seropositivity and determine anti-CagA, VacA virulence factor status of Turkish dyspeptic patients in the Izmir region.

Evaluation of Usefulness of Three Serological Tests Using Native Crude Antigen in Diagnosis of Hepatic Cystic Echinococcosis Patients

Objective: To evaluate three different serological tests [Indirect Hemaglutination (IHA), Enzyme Linked Immunosorbent Assay (ELISA) and Western Blotting (WB)] using native crude antigen for diagnosis of hepatic cystic echinococcosis (HCE) patients. Materials and Methods: Sheep hydatid fluid (HF) was collected from fertile cysts obtained from a slaughterhouse and used as an antigen. Forty patients who were attended the Dr. Ersin Arslan Training and Research Hospital in Gaziantep, Turkey, were investigated. Serum samples were obtained from surgically confirmed CE patients. Healthy Turkish people and 16 patients with other helminthic infections were included as a control group. Results: Of the 40 analyzed patients, 10 (25%) were men and 30 (75%) were female. The average age was 46.97 years (s.d.;18.95). The majority of the patients had a single cystic lesion situated in one lobe of the liver (usually in the right lobe) (55%), 32.5% of patients had two cystic lesions and 12.5% of patients had multiple cyst formations with various numbers. In all cases, ultrasound (US) examinations were positive and the size of cysts was between 2.1 - 12.7 cm. Twenty-three patients of the total 40 patients were classified according to the WHO classification system based on US findings. According to the results of WB analysis, molecular weights of 8 kDa (80%), 12 kDa (80%), 22 - 24 kDa (97.5%), 26 kDa (97.5%), 34 kDa (100%), 36 - 38 kDa (90%), 45 - 50 - 55 kDa (97.5%), and 60 - 75 kDa (97.5%) bands were identified. But 34, 50, and 55 kDa bands were also found in other helminthic diseases. Conclusion: The specificity and sensitivity of three serological tests (IHA, ELISA and WB) using crude antigen were compared by diagnosing hepatic cystic echinococcosis patients. IHA and ELISA showed high sensitivity but low specificity. Western blotting showed low sensitivity but high specificity.

Determination of serum fibrosis indexes in patients with chronic hepatitis and its significance

Objectives To study the relationship between serum levels of hyaluronic acid (HA), type Ⅲ procollagen (PCⅢ), laminin (LN), type Ⅳ collagen (Ⅳ-C) and hepatic fibrosis and to determine their value in clinical practice. Methods 2600 serum samples from chronic hepatitis patients were assayed for fibrosis indexes including HA, PCⅢ, LN and Ⅳ-C with RIA. Liver biopsy was performed in 280 of those patients and the biopsy material was examined histopathologically. The inflammation grade of the liver, stage of fibrosis and degree of chronic hepatitis were recorded and were compared with fibrotic indexes. Results Among 2600 chronic hepatitis patients, every fibrotic index had a significant correlation with the inflammation grade, fibrosis staging and the degree of chronic hepatitis (P<0.01). The coefficient correlation of the results of histopathological examinations to HA was 0.544, 0.548 and 0.468 respectively, that to PCⅢ, 0.495, 0.424 and 0.335, that to LN, 0.214, 0.204 and 0.184, and that to Ⅳ-C, 0.406, 0.404 and 0.412, respectively. Conclusions Serum fibrosis indexes are fairly well correlated with the inflammation grade of the liver, fibrosis staging and the degree of chronic hepatitis. However, as diagnostic markers, they should be considered in combination with liver function tests, ultrasonography and clinical manifestations.

Schistosoma japonicum: construction of phage display antibody library and its application in the immunodiagnosis of infection

Background A monoclonal antibody would be an effective tool for the detection of circulating antigens in the serum of patients with schistosomiasis, but the traditional way of producing monoclonal antibodies is not cost-effective. The objective of this study was to find a new method for the large-scale production of monoclonal antibodies against Schistosoma japonicum (Sj).Methods A phage display antibody library for Sj was constructed. To obtain a single-chain variable fragment antibody (scFv) against Sj, the library was screened with metabolic antigens from adult Sj worms (Sj-MAg) using enzyme-linked immunosorbent assay. The soluble scFvs select ed were used to detect Sj antigens in the serum of acute and chronic schistosomiasis patients.Results Six positive clones with good reactivity to Sj-MAg were obtained from the phage display antibody library of about 1.07×10 6 individual clones. Only two of these six clones bound specifically to Sj-MAg and were chosen for further analysis. Specific soluble anti-Sj-MAg scFvs were produced by inducing the 2 clones with isopropyl-D-thiogalactopyranoside. The characteristics of the scFvs were then determined. The results of Western blot showed that these scFvs could bind to Sj-MAg specifically an d had a molecular weight of about 31 kD. When testing serum from schistosomiasis patients with one of the two specific scFvs, its sensitivity was found to be 60% and 37% in acute and chronic patients, respectively, with a specificity of 90%. When the two specific scFvs were combined, their sensitivity was found to be 75% and 57% in acute and chronic patients, respectively, with a specificity of 85%.Conclusions The results indicate that the scFvs are potentially useful for the diagnosis of schistosomiasis. The library construct ion also provides a useful tool for the further screening of other antibodies for both diagnostic and immunotherapeutic applications and for epitope analysis and vaccine design.

Cloning, Expression, and Homology Modeling of GroEL Protein from Leptospira interrogans Serovar Autumnalis Strain N2

Leptospirosis is an infectious bacterial disease caused by Leptospira species. In this study, we cloned and se- quenced the gene encoding the immunodominant protein GroEL from L. interrogans serovar Autumnalis strain N2, which was isolated from the urine of a patient during an outbreak of leptospirosis in Chennai, India. This groEL gene encodes a protein of 60 kDa with a high degree of homology （99% similarity） to those of other leptospiral serovars. Recombinant GroEL was overexpressed in Escherichia coli. lmmunoblot analysis indi- cated that the sera from confirmed leptospirosis patients showed strong reactivity with the recombinant GroEL while no reactivity was observed with the sera from seronegative control patient. In addition, the 3D structure of GroEL was constructed using chaperonin complex cpn60 from Thermus thermophilus as template and vali- dated. The results indicated a Z-score of -8.35, which is in good agreement with the expected value for a pro- tein. The superposition of the Ca traces of cpn60 structure and predicted structure of leptospiral GroEL indicates good agreement of secondary structure elements with an RMSD value of 1.5A. Further study is necessary to evaluate GroEL for serological diagnosis of leptospirosis and for its potential as a vaccine component.