scholarly journals Antigenicity of Leishmania braziliensis Histone H1 during Cutaneous Leishmaniasis: Localization of Antigenic Determinants

2002 ◽  
Vol 9 (4) ◽  
pp. 808-811 ◽  
Author(s):  
Emma Carmelo ◽  
Enrique Martínez ◽  
Ana Cristina González ◽  
José Enrique Piñero ◽  
Manuel E. Patarroyo ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Chagas Disease ◽  
Expression System ◽  
Protein A ◽  
Histone H1 ◽  
Antigenic Determinants ◽  
Enzyme Linked Immunosorbent Assay ◽  
Leishmania Braziliensis ◽  
Serum Samples ◽  
Prokaryotic Expression System

ABSTRACT The humoral immune response against Leishmania braziliensis histone H1 by patients with cutaneous leishmaniasis is described. For this purpose, the protein was purified as a recombinant protein in a prokaryotic expression system and was assayed by enzyme-linked immunosorbent assay (ELISA) with a collection of sera from patients with cutaneous leishmaniasis and Chagas' disease. The assays showed that L. braziliensis histone H1 was recognized by 66% of the serum samples from patients with leishmaniasis and by 40% of the serum samples from patients with Chagas' disease, indicating that it acts as an immunogen during cutaneous leishmaniasis. In order to locate the linear antigenic determinants of this protein, a collection of synthetic peptides covering the L. braziliensis histone H1sequence was tested by ELISA. The experiments showed that the main antigenic determinant is located in the central region of this protein. Our results show that the recombinant L. braziliensis histone H1 is recognized by a significant percentage of serum samples from patients with cutaneous leishmaniasis, but use of this protein as a tool for the diagnosis of cutaneous leishmaniasis is hampered by the cross-reaction with sera from patients with Chagas' disease.

scholarly journals Optimization and Validation of Indirect ELISA Using Truncated TssB Protein for the Serodiagnosis of Glanders amongst Equines

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Harisankar Singha ◽  
Praveen Malik ◽  
Sachin K. Goyal ◽  
Sandip K. Khurana ◽  
Chiranjay Mukhopadhyay ◽  
...  
Keyword(s):  
Indirect Elisa ◽  
Expression System ◽  
Cross Reactivity ◽  
Amino Acid Sequences ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Diagnostic Efficacy ◽  
Diagnostic Potential ◽  
Prokaryotic Expression System ◽  
Control Serum

Objective. To express truncated TssB protein ofBurkholderia malleiand to evaluate its diagnostic efficacy for serological detection of glanders among equines.Materials and Methods. In an attempt to develop recombinant protein based enzyme-linked immunosorbent assay (ELISA), N-terminal 200 amino acid sequences ofB. malleiTssB protein—a type 6 secretory effector protein—were expressed in prokaryotic expression system. Diagnostic potential of recombinant TssB protein was evaluated in indirect ELISA using a panel of glanders positive (n=49), negative (n=30), and field serum samples (n=1811). Cross-reactivity of the assay was assessed with equine disease control serum and human melioidosis positive serum.Results. In comparison to CFT, diagnostic sensitivity and specificity of ELISA were 99.7% and 100%, respectively.Conclusions. The indirect ELISA method using the truncated TssB offered safer and more rapid and efficient means of serodiagnosis of glanders in equines. These data highlight the use of TssB as potential diagnostic antigen for serological diagnosis of glanders.

scholarly journals A novel multi-epitope recombinant protein for diagnosis of African swine fever

2020 ◽  
Author(s):  
ZHAN GAO ◽  
JUNJUN SHAO ◽  
GUANGLEI ZHANG ◽  
SUDAN GE ◽  
YANYAN CHANG ◽  
...  
Keyword(s):  
Recombinant Protein ◽  
African Swine Fever Virus ◽  
Expression System ◽  
African Swine Fever ◽  
Economic Losses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Sds Page ◽  
Prokaryotic Expression System ◽  
Swine Diseases

Abstract Background: African swine fever(ASF) is an acute, severe and highly fatal infectious disease of pigs. The disease spreads rapidly, causing huge economic losses to the pig industry in infected areas. The structural proteins p30 and p54 in African swine fever virus(ASFV) have been verified as diagnostic antigens.Methods: In this study, we constructed a novel multi-epitope fusion antigen gene based on P30 and P54 proteins, induced expression in a prokaryotic expression system and analyzed the reactivity of the recombinant fusion protein. The purified recombinant protein m35 was used as the coating antigen to establish an indirect enzyme-linked immunosorbent assay (ELISA) detection method for ASFV. 116 serum samples and positive sera of other swine diseases were detected by indirect ELISA.Results: Our results indicate that the m35 gene fragment with a length of 558bp was successfully constructed. SDS-PAGE and Western Blotting analysis showed that the protein had a band at 22kDa, proving its good reactogenicity. ROC analysis was performed to validate the assay, the area under the ROC curve is 0.9738 (95% confidence interval, 0.9336 to 1.014), and does not cross-react with other swine diseases.Conclusion: Our results show that its sensitivity and specificity were highly accurate. It is feasible to use this recombinant protein as a diagnostic antigen to distinguish ASFV infection.

scholarly journals Serological Evaluation of Specific-Antibody Levels in Patients Treated for Chronic Chagas' Disease

2007 ◽  
Vol 15 (2) ◽  
pp. 297-302 ◽  
Author(s):  
Olga Sánchez Negrette ◽  
Fernando J. Sánchez Valdéz ◽  
Carlos D. Lacunza ◽  
María Fernanda García Bustos ◽  
María Celia Mora ◽  
...  
Keyword(s):  
Chagas Disease ◽  
Treatment Effectiveness ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests ◽  
Recombinant Antigens ◽  
Antibody Titers ◽  
Laboratory Procedures ◽  
The Individual ◽  
Antibody Levels

ABSTRACT Serological tests are the main laboratory procedures used for diagnosis during the indeterminate and chronic stages of Chagas' disease. A serological regression to negativity is the main criterion used to define parasitological cure in treated patients. The aim of this work was to monitor the individual specificities of antibody levels for 3 years posttreatment in 18 adult patients. Conventional serological techniques (hemagglutination assays and enzyme-linked immunosorbent assay [ELISA]) were modified by using recombinant antigens to detect early markers of treatment effectiveness. For this purpose, serum samples were taken before and during treatment and every 6 months after treatment for at least 3 years. When hemagglutination assays were used, a decrease in antibody levels was observed in only one patient. When ELISA with serum dilutions was used, antibody clearance became much more apparent: in 77.7% (14/18) of the patients, antibody titers became negative with time. This was observed at serum dilutions of 1/320 and occurred between the 6th and the 30th months posttreatment. The immune response and the interval for a serological regression to negativity were different for each patient. For some of the recombinant antigens, only 50% (9/18) of the patients reached the serological regression to negativity. Recombinant antigen 13 might be a good marker of treatment effectiveness, since 66.6% (six of nine) of the patients presented with an early regression to negativity for specific antibodies to this antigen (P = 0.002).

scholarly journals Recombinant Dense Granular Protein (GRA5) for Detection of Human Toxoplasmosis by Western Blot

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Xiao Teng Ching ◽  
Yee Ling Lau ◽  
Mun Yik Fong ◽  
Veeranoot Nissapatorn ◽  
Hemah Andiappan
Keyword(s):  
Western Blot ◽  
Affinity Purification ◽  
Expression System ◽  
Economic Loss ◽  
Serum Samples ◽  
Serological Tests ◽  
Human Patient ◽  
Prokaryotic Expression System ◽  
Human Sera ◽  
Lysate Antigens

Toxoplasma gondiiinfects all warm-blooded animals, including humans, causing serious public health problems and great economic loss for the food industry. Commonly used serological tests require costly and hazardous preparation of wholeToxoplasmalysate antigens from tachyzoites. Here, we have evaluated an alternative method for antigen production, which involved a prokaryotic expression system. Specifically, we expressedT. gondiidense granular protein-5 (GRA5) inEscherichia coliand isolated it by affinity purification. The serodiagnostic potential of the purified recombinant GRA5 (rGRA5) was tested through Western blot analysis against 212 human patient serum samples. We found that rGRA5 protein was 100% specific for analysis of toxoplasmosis-negative human sera. Also, rGRA5 was able to detect acute and chronicT. gondiiinfections (sensitivities of 46.8% and 61.2%, resp.).

scholarly journals Comparison of Recombinant Trypanosoma cruzi Peptide Mixtures versus Multiepitope Chimeric Proteins as Sensitizing Antigens for Immunodiagnosis

2009 ◽  
Vol 16 (6) ◽  
pp. 899-905 ◽  
Author(s):  
Cecilia Camussone ◽  
Verónica Gonzalez ◽  
María S. Belluzo ◽  
Nazarena Pujato ◽  
María E. Ribone ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Serum Sample ◽  
Chagas Disease ◽  
Single Molecule ◽  
Enzyme Linked Immunosorbent Assay ◽  
Chimeric Proteins ◽  
Serum Samples ◽  
Peptide Mixtures ◽  
Positive Serum ◽  
Recombinant Peptides

ABSTRACT The aim of this work was to determine the best strategy to display antigens (Ags) on immunochemical devices to improve test selectivity and sensitivity. We comparatively evaluated five Trypanosoma cruzi antigenic recombinant peptides, chose the three more sensitive ones, built up chimeras bearing these selected Ags, and systematically compared by enzyme-linked immunosorbent assay the performance of the assortments of those peptides with that of the multiepitope constructions bearing all those peptides lineally fused. The better-performing Ags that were compared included peptides homologous to the previously described T. cruzi flagellar repetitive Ag (here named RP1), shed acute-phase Ag (RP2), B13 (RP5), and the chimeric recombinant proteins CP1 and CP2, bearing repetitions of RP1-RP2 and RP1-RP2-RP5, respectively. The diagnostic performances of these Ags were assessed for discrimination efficiency by the formula +OD/cutoff value (where +OD is the mean optical density value of the positive serum samples tested), in comparison with each other either alone, in mixtures, or as peptide-fused chimeras and with total parasite homogenate (TPH). The discrimination efficiency values obtained for CP1 and CP2 were 25% and 52% higher, respectively, than those of their individual-Ag mixtures. CP2 was the only Ag that showed enhanced discrimination efficiency between Chagas' disease-positive and -negative samples, compared with TPH. This study highlights the convenience of performing immunochemical assays using hybrid, single-molecule, chimeric Ags instead of peptide mixtures. CP2 preliminary tests rendered 98.6% sensitivity when evaluated with a 141-Chagas' disease-positive serum sample panel and 99.4% specificity when assessed with a 164-Chagas' disease-negative serum sample panel containing 15 samples from individuals infected with Leishmania spp.

scholarly journals Serodiagnosis of Anthroponotic Cutaneous Leishmaniasis (ACL) Caused by Leishmania tropica in Sanliurfa Province, Turkey, Where ACL Is Highly Endemic

2007 ◽  
Vol 14 (11) ◽  
pp. 1409-1415 ◽  
Author(s):  
Fadile Yildiz Zeyrek ◽  
Metin Korkmaz ◽  
Yusuf Özbel
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Western Blotting ◽  
Blood Donors ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Serological Tests ◽  
Western Blot Test ◽  
Conventional Elisa ◽  
Negative Controls ◽  
Positive Controls

ABSTRACT In this study, we aimed to evaluate the validity of the conventional enzyme-linked immunosorbent assay (ELISA) and the Western blotting test for the diagnosis of anthroponotic cutaneous leishmaniasis (ACL) using serum samples obtained from 51 patients with parasitologically proven nontreated CL (NonT-CL patients) and 62 patients under treatment for CL (UT-CL patients). Additionally, 29 serum samples obtained from patients with parasitologically and serologically proven visceral leishmaniasis (VL) were also used as positive controls, and serum samples from 43 blood donors were used as negative controls. All sera were diluted to the same dilution (1/100). Leishmania infantum MON-1 was used as the antigen in the conventional ELISA. The sera of 27 (93.1%) of 29 VL patients were seropositive by ELISA, while the sera of 40 (78.4%) of 51 NonT-CL patients and 43 (69.3%) of 62 UT-CL patients were seropositive by the conventional ELISA. The absorbance values of the CL patients' sera were significantly lower than the absorbance values of the VL patients' sera. Bands between 15 and 118 kDa were detected in two groups of CL patients. Among all bands, the 63-kDa band was found to be more sensitive (88.5%). When we evaluated the Western blotting results for the presence of at least one of the diagnostic antigenic bands, the sensitivity was calculated to be 99.1%. By using serological tests, a measurable antibody response was detected in most of the CL patients in Sanliurfa, Turkey. It is also noted that this response can be changed according to the sizes, types, and numbers of lesions that the patient has. The Western blot test was found to be more sensitive and valid than the conventional ELISA for the serodiagnosis of ACL. In some instances, when it is very difficult to demonstrate the presence of parasites in the smears, immunodiagnosis can be a valuable alternative for the diagnosis of ACL.

scholarly journals Cross-reactivity of antibodies in human infections by the kinetoplastid protozoa Trypanosoma cruzi, Leishmania chagasi and Leishmania (Viannia) braziliensis

1996 ◽  
Vol 38 (3) ◽  
pp. 177-185 ◽  
Author(s):  
Ana de Cássia Vexenat ◽  
Jaime M. Santana ◽  
Antonio R.L. Teixeira
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Cross Reactivity ◽  
Antigenic Determinants ◽  
Leishmania Braziliensis ◽  
Leishmania Chagasi ◽  
Mucocutaneous Leishmaniasis ◽  
Kala Azar ◽  
Homologous Antigen ◽  
Positive Results

We have detected antibodies, in the sera of Chagas disease, Kala-azar and Mucocutaneous leishmaniasis patients, that bind multiple antigens shared between the three causative agents. The Chagas disease sera showed 98 to 100% positive results by ELISA when the Leishmania braziliensis and Leishmania chagasi antigens were used, respectively. The Kala-azar sera showed 100% positive results with Trypanosoma cruzi or L. braziliensis antigens by immunofluorescence assays. The antibodies in the sera of Mucocutaneous leishmaniasis patients showed 100% positive results by ELISA assays with T. cruzi or L. chagasi antigens. Furthermore, the direct agglutination of L. chagasi promastigotes showed that 95% of Kala-azar and 35% of Mucocutaneous leishmaniasis sera agglutinated the parasite in dilutions above 1:512. In contrast, 15% of Chagas sera agglutinated the parasite in dilutions 1:16 and below. Western blot analysis showed that the Chagas sera that formed at least 24 bands with the T. cruzi also formed 13 bands with the L. chagasi and 17 bands with the L. braziliensis. The Kala-azar sera that recognized at least 29 bands with the homologous antigen also formed 14 bands with the T. cruzi and 10 bands with the L. braziliensis antigens. Finally, the Mucocutaneous leishmaniasis sera that formed at least 17 bands with the homologous antigen also formed 10 bands with the T. cruzi and four bands with the L. chagasi antigens. These results indicate the presence of common antigenic determinants in several protozoal proteins and, therefore, explain the serologic cross-reactions reported here.

scholarly journals Horseradish Peroxidase-Conjugated-Nanobody-Based cELISA For The Rapid and Sensitive Clinical Detection of African Swine Fever Virus Antibodies

2021 ◽  
Author(s):  
Huijun Zhao ◽  
Jiahui Ren ◽  
Shuya Wu ◽  
Yongkun Du ◽  
Bo Wan ◽  
...  
Keyword(s):  
Horseradish Peroxidase ◽  
Fusion Protein ◽  
Expression System ◽  
African Swine Fever ◽  
Enzyme Linked Immunosorbent Assay ◽  
Hemorrhagic Disease ◽  
Serum Samples ◽  
Promising Alternative ◽  
Technical Requirements ◽  
Pig Serum

Abstract Background: African swine fever (ASF), which is caused by the ASF virus (ASFV), is a highly contagious hemorrhagic disease that affects pigs and has the potential to cause mortality in almost 100% of domestic pigs and wild boars. Due to the lack of an effective vaccine, the control of ASF must depend on early, efficient, cost-effective detection and strict control and elimination strategies. Traditional molecular and serological testing methods are generally associated with high testing costs, complex operations and high technical requirements. As a promising alternative diagnostic tool to traditional antibodies, nanobodies (Nb) have the advantages of simpler and faster generation, good stability and solubility, and high affinity and specificity. The application of Nbs in the detection of ASFV antibodies in the serum has not yet been reported, to the best of our knowledge. Results: Using a phage display technology, one specific Nb against the ASFV p54 protein that exhibited high specificity and affinity to the protein, Nb8, was successfully screened. A HEK293T cell line stably expressing Nb8-horseradish peroxidase (HRP) fusion protein was established using the lentiviral expression system. Following the optimization of the reaction conditions, the Nb8-HRP fusion protein was successfully used to establish a competitive enzyme-linked immunosorbent assay (cELISA) to detect ASFV-specific antibodies in pig serum, for the first time. The cut-off value for the cELISA was 15.78%. A total of 209 serum samples were tested using the developed cELISA and a commercial ELISA kit. The specificity of the cELISA was 98.97%, and the limit of detection was 1:320 in inactivated ASFV antibody-positive reference serum samples, with the coincidence rate between the two methods being 98.56%. Conclusions: A specific, sensitive and repeatable cELISA was successfully developed based on the unique Nb8 as a probe, providing a promising method for the detection of anti-ASFV antibodies in clinical pig serum.

scholarly journals Modified Immunogenicity of a Mucosally Administered Antigen

2001 ◽  
Vol 8 (3) ◽  
pp. 540-544 ◽  
Author(s):  
Richard L. Gregory
Keyword(s):  
Immune System ◽  
Immunoglobulin A ◽  
Human Saliva ◽  
Mucosal Immune System ◽  
Antigenic Determinants ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Naturally Occurring ◽  
The Common

ABSTRACT Streptococcus mutans is present in the saliva of most individuals and is modified by salivary components bound to the cells. These saliva-bound S. mutans are swallowed, exposed to high levels of acidity in the stomach, and presented to the common mucosal immune system. Much effort has been directed to identifying the specific S. mutans antigens that the mucosal immune responses are directed against. However, little is known about the host-altered antigenic determinants that the mucosal immune system recognizes. The immunogenicity of gastrically intubated untreatedS. mutans cells, cells coated with whole human saliva, cells treated with HCl (pH 2.0), and saliva-coated and acid-treated cells in mice was investigated. Saliva and serum samples were assayed by enzyme linked immunosorbent assay for immunoglobulin A (IgA) and IgG antibodies, respectively, against the untreated or treated S. mutans cells. In general, the levels of salivary IgA and serum IgG antibodies to the antigen against which the mice were immunized were significantly higher (P ≤ 0.05). In addition, human saliva and serum samples from 12 subjects were assayed for naturally occurring antibody against the untreated or treated S. mutans cells. In every case, significantly higher reactivity was directed against the saliva-coated and acid-treated cells followed by the saliva-coated S. mutans. These results provide evidence for the altered immunogenicity of swallowed S. mutans in humans by coating native S. mutans antigens with salivary components and/or denaturing surface S. mutans antigens in the acidic environment of the stomach, which would lead to an immune response to modified S. mutans determinants and not to native S. mutans antigens.

Expression of Recombinant Human Cytomegalovirus Fusion Proteins pp150-pp65 Fragments and its Application

2013 ◽  
Vol 634-638 ◽  
pp. 1313-1318
Author(s):  
Yu Fen Jin ◽  
Yan Lei Li ◽  
Yan Hua ◽  
Xiao Gang Zhang ◽  
Ting Yu
Keyword(s):  
Fusion Protein ◽  
Western Blot ◽  
Human Cytomegalovirus ◽  
Colloidal Gold ◽  
Fusion Proteins ◽  
Prokaryotic Expression ◽  
Expression System ◽  
Serum Samples ◽  
Igg Antibody ◽  
Prokaryotic Expression System

Objective To evaluate the effectiveness of prokaryotic expression of fusion proteins pp150-pp65 of human cytomegalovirus (hCMV) for its application as antigen, the fusion protein of pp150-pp65 were expressed in prokaryotic expression system and purified by Ni-NTA affinity chromatography column for preparing the colloidal gold kit. Methods Using DNA from HCMV strain as template, the genes encoding pp150 and pp65 protein fragment were amplified by PCR technique, respectively. After confirmed by DNA sequence analysis, the recombinant plasmid pET28a-pp150-pp65 was transformed into E.Coil.BL21(DE3) and induced to express with IPTG. The expressed fusion protein was characterized by SDS-PAGE and western blot after purified, then we used the purified fusion protein to develop combined detection kit of IgM/IgG antibody against HCMV (colloidal gold method) with Beijing Innovita Bio-tech Co., Ltd for detecting the samples, compared with the imported kits (ELISA). Results The gene of fusion fragment pp150-pp65 was correctly amplified and the recombinant vector was successfully constructed. The purified protein with the molecular weight of 45KD had good antigenicity by western blot. The protein was subjected to assay with an ELI SA capture kit in its specific and sensitive assay based on colloidal gold nanoparticles, testing of 600 serum samples indicated that this kit had a sensitivity of 92.7%;, specificity of 83.1%, crude consistency o f 90.2%, compared to the imported HCMV-IgG kit; the sensitivity of the kit was 88.1%, specificity was 89.2%, coarse consistency was 88.5%, compared to the imported HCMV-IgM kit; Conclusion In this experiment, the HCMV antigen with high purity and specificity (pp150-pp65 recombinant protein) was prepared effectively through genetic engineering technology. Compared to imported reagents, the colloidal gold kit consisting of fusion protein in a capture assay had high sensitivity and specificity. Preliminary clinical use warrants further development and use of this kit. Furthermore, it provides a technological basis for detection of HCMV in different stages of clinical infection.

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