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Farzaneh M, Derakhshandeh A, Al-Farha AABA, Petrovski K, Hemmatzadeh F. A novel phage-displayed MilA ELISA for detection of antibodies against Myc. bovis in bovine milk. J Appl Microbiol 2022; 133:1496-1505. [PMID: 35686656 PMCID: PMC9545076 DOI: 10.1111/jam.15655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/29/2022] [Accepted: 06/04/2022] [Indexed: 12/01/2022]
Abstract
AIMS The aim of this study was to assess a phage-displayed MilA protein of Myc. bovis in an indirect ELISA for the detection of Myc. bovis antibodies in milk samples. METHODS AND RESULTS The desired sequence of milA gene was synthesized and cloned into pCANTAB-F12 phagemid vector. The expression of the MilA on the phage surface was confirmed by Western blotting. The recombinant phage was used in the development of an indirect ELISA to detect Myc. bovis antibodies in milk samples. There was a significant agreement between the results of phage-based ELISA and recombinant GST-MilA ELISA for the detection of Myc. bovis antibodies in milk samples. CONCLUSIONS The inexpensive and convenient phage-based ELISA can be used instead of recombinant protein/peptide ELISA as an initial screening of Myc. bovis-associated mastitis. SIGNIFICANCE AND IMPACT OF STUDY Mastitis associated with Myc. bovis is a continuous and serious problem in the dairy industry. Sero-monitoring of Myc. bovis infection cases are one of the key factors for surveillance of the infections in dairy farms. Despite the existence of some commercially serological assays for Myc. bovis antibodies, they have some limitations regarding their sensitivity and availability. The development of accurate diagnosis tools could contribute to control programmes of Myc. bovis-associated mastitis in the dairy herds.
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Suo B, He J, Wu C, Wang D. Comparison of Different Laboratory Methods for Clinical Detection of Brucella Infection. Bull Exp Biol Med 2021; 172:223-227. [PMID: 34853970 DOI: 10.1007/s10517-021-05367-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 11/30/2022]
Abstract
The rapidity, accuracy, and detection abilities of different laboratory methods (tube agglutination test (SAT), indirect ELISA, fluorescence polarization test (FPA), and blood culture methods) to detect Brucella in the laboratory. The study included 95 patients with documented and 42 patients with suspected brucellosis and 56 healthy control subjects. For the tests, the positive rates of Brucella infection detection in the confirmed group were significantly higher than in group with suspected infection (p<0.01) and in healthy controls (p<0.01). There was no significant difference between indirect ELISA and FPA in detecting antibodies to Brucella in acute (χ2=0.335), subacute (χ2=0.660), and chronic cases (χ2=5.332). Among the detection methods, indirect ELISA showed the highest sensitivity (98.9%), specificity (100%), and Youden index (0.989). The sensitivity and specificity of FPA were 96.8 and 96.4%, respectively. In order to easily and rapidly diagnose brucellosis in clinical practice, a combination of detection methods is recommended, in which Brucella antibodies are screened by FPA and then confirmed by indirect ELISA.
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Mamo T, Yimer L. Serological Investigation of Newcastle Disease in Selected Districts of Buno Bedelle Zone, Ethiopia. VETERINARY MEDICINE-RESEARCH AND REPORTS 2021; 12:253-259. [PMID: 34616667 PMCID: PMC8488029 DOI: 10.2147/vmrr.s327892] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 09/21/2021] [Indexed: 12/29/2022]
Abstract
Purpose Newcastle disease causes considerable loss in the poultry industry worldwide and its outbreaks are regularly reported from all continents of the world, including Ethiopia. The investigation was conducted from October 2020 to June 2021 to determine the prevalence of Newcastle disease (ND) in districts selected from Buno Bedele zone, Western Oromia. Methods The study design used was a cross-sectional type. For this study, a total of 480 serum samples were collected as per sample collection guideline from randomly selected chickens that were apparently healthy and had no history of vaccination against Newcastle disease. Indirect ELISA was performed and all data were analyzed using SPSS statistical software. Results From serological investigation, overall seroprevalence of Newcastle disease was 30%. Seroprevalence of Newcastle disease was 34.94%, 22.22%, and 31.76% in Didessa, Chora, and Gachi districts, respectively. Among computed risk factors, breed showed statistically significant difference and the odds of infection were lower in adult than in young chickens. Similarly, the odds of infection with Newcastle disease virus were significantly higher in crossbred than in locally bred backyard chickens. Conclusion This study revealed Newcastle disease was prevalent in the study areas; therefore, regular investigation of Newcastle disease should be conducted along with detailed studies on molecular characterization of circulating field strains in the area.
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HIGH PREVALENCE OF CIRCULATING ANTIBODIES TO RENIBACTERIUM SALMONINARUM IN SPAWNING ONCORHYNCHUS SPP. FROM LAKE MICHIGAN, USA. J Wildl Dis 2021; 57:19-26. [PMID: 33635967 DOI: 10.7589/2019-04-098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 12/11/2019] [Indexed: 11/20/2022]
Abstract
Bacterial kidney disease, caused by Renibacterium salmoninarum, threatens salmonids worldwide. Following devastating mortality episodes in Oncorhynchus spp. in Lake Michigan, US, in the 1980s and infection rates >90%, pathogen prevalence has steadily declined to <5% over three decades in the three state-managed stocks. In this study, we sought to determine if the declining infection rates were associated with heightened circulating antibodies in state-managed Oncorhynchus spp. residing in the Lake Michigan watershed. A single-dilution, indirect enzyme-linked immunosorbent assay (ELISA) was modified to detect circulating antibodies against R. salmoninarum. Baseline values were delineated from naive chinook salmon (Oncorhynchus tshawytscha) and rainbow trout (Oncorhynchus mykiss). The assay was first used to assess primary antibody production over a 4-wk period in chinook salmon experimentally infected with R. salmoninarum. Mean antibody response was detected as early as 2 wk postinfection and continued to increase to the end of the observation period. The modified ELISA was then used to detect antibodies in serum samples collected from feral adult chinook salmon, coho salmon (Oncorhynchus kisutch), and steelhead trout (O. mykiss) returning to spawn at Lake Michigan weirs in 2009 and 2013. Results demonstrated that about 80% of feral Oncorhynchus spp. had measurable titers of circulating antibodies to R. salmoninarum. The relative ease and reasonable costs of this modified ELISA makes it a valuable serosurveillance tool for assessing the humoral immune status of feral salmonid populations.
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Mazziotta C, Lanzillotti C, Torreggiani E, Oton-Gonzalez L, Iaquinta MR, Mazzoni E, Gaboriaud P, Touzé A, Silvagni E, Govoni M, Martini F, Tognon M, Rotondo JC. Serum Antibodies Against the Oncogenic Merkel Cell Polyomavirus Detected by an Innovative Immunological Assay With Mimotopes in Healthy Subjects. Front Immunol 2021; 12:676627. [PMID: 34168646 PMCID: PMC8217635 DOI: 10.3389/fimmu.2021.676627] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/20/2021] [Indexed: 12/22/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV), a small DNA tumor virus, has been detected in Merkel cell carcinoma (MCC) and in normal tissues. Since MCPyV infection occurs in both MCC-affected patients and healthy subjects (HS), innovative immunoassays for detecting antibodies (abs) against MCPyV are required. Herein, sera from HS were analyzed with a novel indirect ELISA using two synthetic peptides mimicking MCPyV capsid protein epitopes of VP1 and VP2. Synthetic peptides were designed to recognize IgGs against MCPyV VP mimotopes using a computer-assisted approach. The assay was set up evaluating its performance in detecting IgGs anti-MCPyV on MCPyV-positive (n=65) and -negative (n=67) control sera. Then, the ELISA was extended to sera (n=548) from HS aged 18-65 yrs old. Age-specific MCPyV-seroprevalence was investigated. Performance evaluation indicated that the assay showed 80% sensitivity, 91% specificity and 83.9% accuracy, with positive and negative predictive values of 94.3% and 71%, respectively. The ratio expected/obtained data agreement was 86%, with a Cohen's kappa of 0.72. Receiver-operating characteristic (ROC) curves analysis indicated that the areas under the curves (AUCs) for the two peptides were 0.82 and 0.74, respectively. Intra-/inter-run variations were below 9%. The overall prevalence of serum IgGs anti-MCPyV in HS was 62.9% (345/548). Age-specific MCPyV-seroprevalence was 63.1% (82/130), 56.7% (68/120), 64.5% (91/141), and 66.2% (104/157) in HS aged 18-30, 31-40, 41-50 and 51-65 yrs old, respectively (p>0.05). Performance evaluation suggests that our indirect ELISA is reliable in detecting IgGs anti-MCPyV. Our immunological data indicate that MCPyV infection occurs asymptomatically, at a relatively high prevalence, in humans.
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Ding H, Wen Y, Xu Z, Zhou B, Tlili C, Tian Y, Wang Z, Ning Y, Xin J. Development of an ELISA for distinguishing convalescent sera with Mycoplasma hyopneumoniae infection from hyperimmune sera responses to bacterin vaccination in pigs. Vet Med Sci 2021; 7:1831-1840. [PMID: 34021737 PMCID: PMC8464267 DOI: 10.1002/vms3.539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 12/16/2022] Open
Abstract
Vaccination with inactivated bacterin is the most popular and practical measure to control enzootic pneumonia. After immunisation with inactivated bacterin, Mycoplasma hyopneumoniae colonised on the respiratory tract and lung stimulates the humoural immune responses and produces IgG and IgA antibodies. ELISA is a widely used serological method to detect M. hyopneumoniae antibodies. However, commercial IgG‐ELISA kit cannot distinguish between inactivated bacterin‐induced hyperimmune sera and convalescent sera stimulated by natural infection. SIgA‐ELISA method needs to collect nasal swabs, but collecting nasal swabs is not easy to operate. Establishment of a discriminative ELISA detecting humoural IgG from convalescent sera but not hyperimmune sera facilitates to evaluate the natural infection of M. hyopneumoniae after inactivated bacterin vaccination. We expressed and purified a recombinant protein named Mhp366‐N which contains an epitope recognised by the convalescent sera but not hyperimmune sera. The developed discriminative IgG‐ELISA could discriminate between inactivated bacterin‐induced hyperimmune sera and convalescent sera and was reproducible, sensitive and specific to M. hyopneumoniae antibody produced by natural infection. Compared to SIgA‐ELISA method, discriminative IgG‐ELISA was more convenient to detect IgG antibody from sera than IgA from nasal swabs, although it has limited sensitivity in the early stages of infection. Additionally, to some extent, it has a potential to avoid the interference of maternally derived IgG antibodies. The established discriminative IgG‐ELISA was efficient to judge the serological IgG antibodies induced from natural infection or inactivated vaccine stimulation and provided a useful method to investigate and evaluate the live organism infection after the application of inactivated bacterin.
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Yuan Y, Yu L, Jin Z, Wang Y, Gao M, Ding H, Zhuo X, Zhu X, Gao F, Zheng X, Ying G, Xu X, Kong Q, Lu S, Lv H. Predictive Analysis of the Neutralization Activity in Convalescent Plasmas From COVID-19 Recovered Patients in Zhejiang Province, China, January-March, 2020. Front Cell Infect Microbiol 2021; 11:650487. [PMID: 33796489 PMCID: PMC8008148 DOI: 10.3389/fcimb.2021.650487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/19/2021] [Indexed: 12/23/2022] Open
Abstract
Background Convalescent plasma (CP) transfusion is considered to be the priority therapeutic option for COVID-19 inpatients when no specific drugs are available for emerging infections. An alternative, simple, and sensitive method is urgently needed for clinical use to detect neutralization activity of the CP to avoid the use of inconvenient micro-neutralization assay. Method This study aims to explore optimal index in predicting the COVID-19 CP neutralization activity (neutralizing antibody titers, NAb titers) in an indirect ELISA format. Fifty-seven COVID-19-recovered patients plasma samples were subjected to anti-SARS-CoV-2 RBD, S1, and N protein IgG antibody by indirect ELISA. Results ELISA-RBD exhibited high specificity (96.2%) and ELISA-N had high sensitivity (100%); while ELISA-S1 had low sensitivity (86.0%) and specificity (73.1%). Furthermore, ELISA-RBD IgG titers and pseudovirus-based NAb titers correlated significantly, with R2 of 0.2564 (P < 0.0001). Conclusion ELISA-RBD could be a substitute for the neutralization assay in resource-limited situations to screen potential plasma donors for further plasma infusion therapy.
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Ali MZ, Shaon MTW, Moula MM, Bary MA, Al Momen Sabuj A, Khaled SA, Bhuiyan ZA, Giasuddin M. First report on the seroprevalence of avian encephalomyelitis virus antibody in Sonali (cross-bred) chickens in Bogura, Bangladesh. J Adv Vet Anim Res 2021; 8:78-83. [PMID: 33860016 PMCID: PMC8043337 DOI: 10.5455/javar.2021.h488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 10/05/2020] [Accepted: 10/06/2020] [Indexed: 11/03/2022] Open
Abstract
Objectives The study intended to detect the presence and distribution of avian encephalomyelitis virus (AEV)-specific antibodies in Sonali (cross-bred) parent chickens regarding farm location, flock size, and age in Bogura district of Bangladesh, a Sonali chicken belt. Materials and methods A total of 275 Sonali parent chickens' blood samples were collected randomly from 39 flocks during laying age with a healthy and non-vaccination history against AEV. Blood samples were collected aseptically from the wing veins of chickens using 3-ml syringes and sera were separated. Then, the sera were transferred to the laboratory by maintaining a cool chain. Indirect enzyme-linked immunosorbent assay was used to detect the specific antibodies against AEV present in the sera samples. Results Overall, 70.18% of the chickens were found seropositive for AEV antibodies. Based on the location, the highest seropositivity was recorded in Bogura Sadar [91.30%, confidence intervals (CI) 79.21%-97.58%], and the lowest was in the Adomdighi sub-district (45.45%, CI 29.49%-63.08%). For flock size, AEV seropositivity was significantly (p < 0.05) higher in the large flock (82.22%, CI 72.74%-89.48%). Regarding age groups, the seropositivity of AEV was significantly (p < 0.05) increased with chickens' age. Higher seropositivity was noted in chickens aged >51 weeks (89.32%, CI 81.69%-94.55%). Conclusion The results indicate that AEV is circulating in the environment, and chickens were exposed to the field strain of AEV. To the best of our knowledge, this is the first report on AEV in chickens in Bangladesh. Proper vaccination and standard farm biosecurity practice could minimize AEV infection in chickens. A detailed epidemiology study, detection, and characterization of the AEV would be essential for effective AEV infection control.
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Shi L, Tian Z, Yang J, Gao S, Du J, Zhao Y, Liu Z, Guan G, Liu G, Luo J, Yin H. [Comparison of the antigenicity of African swine fever virus p35 protein as diagnostic antigen]. SHENG WU GONG CHENG XUE BAO = CHINESE JOURNAL OF BIOTECHNOLOGY 2021; 37:187-195. [PMID: 33501800 DOI: 10.13345/j.cjb.200359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to screen African swine fever virus (ASFV) diagnostic antigen with the best enzyme linked immunosorbent assay (ELISA) reactivity. By establishing the ELISA method, the diagnostic antigen of ASFV p30 protein expressed by baculovirus-insect cell expression system as reference, we explored the antigenic properties and diagnostic potential of ASFV p35 protein expressed by prokaryotic expression system as a diagnostic antigen. The results of Western blotting and immunofluorescence show that the molecular weight of the recombinant p35 protein and p30 protein obtained was 40 kDa and 30 kDa, respectively, and these two proteins had good immuno-reactivity with ASFV positive serum. Recombinant p30 and p35 proteins were used as diagnostic antigens to establish ELISA, and the sensitivity and repeatability of these methods were tested. The results show that although the detection sensitivity of the p30-ELISA established in this study was higher than that of the p35-ELISA, the sensitivity of p35-ELISA was 95.8%, and variations in intra- and inter-assay repeatability of the two methods were less than 10%. The coincidence rate between the p35-ELISA and the imported kit was 97.2%. Results show that p35-ELISA was sensitive and stable, and could detect specific antibodies against ASFV.
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Bhartiya NM, Husain AA, Daginawala HF, Singh L, Kashyap RS. Development of an Immunodiagnostic Test for Screening Human Brucellosis Cases Using the Whole-Cell Antigens of Brucella abortus. Malays J Med Sci 2021; 27:15-26. [PMID: 33447131 PMCID: PMC7785268 DOI: 10.21315/mjms2020.27.6.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 09/21/2017] [Indexed: 11/23/2022] Open
Abstract
Background Human brucellosis is an important zoonotic disease of public health and often remains neglected owing to lack of sensitive and efficient diagnostic methods. This study evaluates diagnostic utility of in-house designed enzyme-linked immunosorbent assay (ELISA) using whole-cell antigens of Brucella abortus (B. abortus) S19 against the commercially available kits. Methods A prospective cohort study involving different populations within the Vidarbha regions of Maharashtra, India was conducted through camps organised from May 2009 to October 2015. A total of 568 serum samples were collected from high-risk people recruited as study cohorts based on inclusion criteria, additional risk factors and clinical symptoms. Samples were evaluated by indirect ELISA using the whole-cell antigens of B. abortus. The results were compared with the commercially available IgG detection ELISA kit to ascertain the specificity and sensitivity of the developed test. Results Fever, body ache, joint pain, lower back pain, loss of appetite and weight loss were major symptoms associated with the disease. With the cut-off of > 0.8, the positivity of brucellosis infection was at 12.32% (70/568) compared to 9.33% (53/568) as detected by the commercial kit. The in-house developed ELISA method yielded a sensitivity of 87.5% and specificity of 99.18% as compared to the commercial kits (sensitivity −80.30% and specificity −99.6%). Discussion The B. abortus S19-derived whole-cell protein-based ELISA is rapid and cost-effective and can be used for screening brucellosis infection in lieu of the commercially available ELISA kits.
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Moghaddam P, Zahmatkesh A, Bagheri M, Mahravani H. Are Epitopic Sites of 3AB and 3D Nonstructural Proteins Sufficient for Detection of Foot and Mouth Disease? Viral Immunol 2020; 34:79-85. [PMID: 33296262 DOI: 10.1089/vim.2020.0144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An efficient method for detection of foot and mouth disease (FMD) and, particularly, differentiation of vaccinated from infected animals is the use of nonstructural (NS) proteins as antigens in Enzyme-Linked Immunosorbent Assay (ELISA) Kits. In this study, only epitopic regions of 3AB and 3D NS proteins were used for recombinant protein production, as a cost-effective method instead of peptide synthesis, for application in in-house ELISA diagnostic kits. Specific primers were designed according to the antigenic regions of 3AB (C-terminus of 3A and the whole 3B) and 3D (N-terminus) proteins, and the polymerase chain reaction (PCR) amplification was performed. Purified amplicons were cloned into pET21a (+) vectors and then transformed into Escherichia coli (BL21). Thereafter, bacteria were induced with 1 mM isopropyl β-d-1-thiogalactopyranoside (IPTG) for expression of antigenic proteins. Antigenic 3AB protein was expressed in soluble form, but 3D protein was extracted from the bacterial lysate. Protein expression was confirmed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analyses. An indirect ELISA was developed for each protein, and the diagnostic sensitivity and specificity were determined. The 3AB-ELISA showed higher sensitivity and specificity than 3D-ELISA (95.24% and 100%, compared with 90.48% and 88.71%, respectively). The epitopic 3AB-ELISA developed here can be used for detection and differentiation of FMD infected from vaccinated animals, but the epitopic 3D-ELISA showed lower efficiency in screening for FMD status.
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Qin Y, Sha R, Feng Y, Huang Y. Comparison of double antigen sandwich and indirect enzyme-linked immunosorbent assay for the diagnosis of hepatitis C virus antibodies. J Clin Lab Anal 2020; 34:e23481. [PMID: 33245583 PMCID: PMC7676215 DOI: 10.1002/jcla.23481] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/10/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The aim of this study is to compare double-antigen sandwich enzyme-linked immunosorbent assay (ELISA) and indirect ELISA in the diagnosis of hepatitis C virus(HCV)infection. METHODS AND MATERIALS A total of 176 samples from the Tumor Hospital Affiliated to Xin Jiang Medical University were utilized to comparison. All serum samples were tested using double-antigen sandwich ELISA and indirect ELISA. Cohen's kappa statistics were used to assess the agreement between the two assays, and multivariate analysis was used to evaluate risk factors for the discordance between the double-antigen ELISA and indirect ELISA. RESULTS The positivities of indirect ELISA (Beijing Wantai), double-antigen sandwich ELISA (Beijing Wantai), and indirect ELISA (Beijing Jinhao) were 74.43%, 68.75%, and 73.30%, respectively. The agreement between the indirect ELISA (Beijing Wantai) and double-antigen sandwich ELISA (Beijing Wantai) was high (κ = 0.829;P < .001), and the agreement between the double-antigen sandwich ELISA (Beijing Wantai) and indirect ELISA (Beijing Jinhao) was high (κ = 0.847;P < .001). Variables associated with discordant results between the double-antigen sandwich and indirect ELISA in multivariate analysis were as follows: female (OR:1.462; P < .05), age (<35 years old; OR:3.667; P < .05), and cancer (suffer from malignant tumor; OR:3.621; P < .05). CONCLUSION In detection of HCV, high agreement was found between the double-antigen sandwich ELISA and indirect ELISA. Female, younger age, and suffer from malignant tumor were significant risk factors for the discordance. Based on double-antigen sandwich ELISA has distinct methodological advantages over indirect ELISA. It is recommended for the diagnosis of HCV infection.
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Validation of a Novel ELISA for the Diagnosis of Hemorrhagic Septicemia in Dairy Cattle from Thailand Using a Bayesian Approach. Vet Sci 2020; 7:vetsci7040163. [PMID: 33126576 PMCID: PMC7711448 DOI: 10.3390/vetsci7040163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 10/21/2020] [Accepted: 10/26/2020] [Indexed: 11/19/2022] Open
Abstract
The objective of this study was to estimate sensitivity (Se) and specificity (Sp) of a novel enzyme-linked immunosorbent assay (ELISA) test (using a coating antigen from Pasteurella multocida M-1404 via heat extraction) and an indirect hemagglutination (IHA) test for detection of Hemorrhagic septicemia (HS) in dairy cows, under Thai conditions, using a Bayesian approach. Dairy cow sera with a total of 1236 samples from 44 farms were tested with the two tests to detect immune responses against the HS. Percentages of positive samples for the ELISA and IHA tests were 73% (901/1236) and 70% (860/1236), respectively. Estimated sensitivity and estimated specificity of the ELISA test were 90.5% (95% posterior probability interval (PPI) = 83.2–95.4%) and 70.8% (95% PPI = 60.8–79.8%), respectively. Additionally, estimates for the Se and Sp values of the IHA test were 77.0% (95% PPI = 70.8–84.1%) and 51.1% (PPI = 36.8–66.3%), respectively. The estimated prevalence of the disease was 71.7% (95% PPI = 62.7–82.6%). These results demonstrate that the ELISA test can be a useful tool for the detection of the presence of an antibody against the HS in dairy cows. Notably, the cows in this area indicated a high percentage of exposure to Pasteurella multocida.
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Chen Q, Rong J, Li G, Xu B, Wang X, Hu J, Rong M, Li H. Establishment of a Rep' protein antibody detection method to distinguish natural infection with PCV2 from subunit vaccine immunization. J Med Microbiol 2020; 69:1183-1196. [PMID: 32812860 DOI: 10.1099/jmm.0.001230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Introduction. PCV2 is a DNA virus that exists widely in pigs and has caused great economic losses to the pig industry worldwide. In the existing commercial PCV2 enzyme-linked immunosorbent assay (ELISA) kits both natural infection with PCV2 and vaccine immunization produce results that are positive for PCV2 Cap antibodies and therefore they cannot diagnose PCV2 infection in immunized pig farms.Aim. To establish a PCV2 non-structural protein antibody detection method that distinguishes between antibodies resulting from natural prior exposure (infection) and those induced by subunit vaccine immunization.Methodology. Based on the non-structural Rep' protein, we established an indirect ELISA (iELISA) using sera from guinea pigs and piglets.Results. The results for iELISA for guinea pig serum showed that animals vaccinated with a whole-virus inactivated PCV2 vaccine had 100 % (10/10) Cap antibody positivity and 100 % (10/10) Rep' antibody positivity. Guinea pigs vaccinated with a recombinant subunit PCV2 vaccine had 100 % (10/10) Cap antibody positivity, while no (0/10) guinea pigs were Rep' antibody-positive. The combined detection results for the Rep' iELISA and a PCV2 Antibody Test kit (Commercial) showed that pigs vaccinated with a whole-virus inactivated PCV2 vaccine or PCV2 SD/2017 had 100 % (5/5) Cap antibody positivity and 100 % (5/5) Rep' antibody positivity. Pigs vaccinated with a recombinant subunit PCV2 vaccine had 100 % (5/5) Cap antibody positivity, while no (0/10) pigs were Rep' antibody-positive.Conclusion. This paper describes an effective iELISA method that can distinguish natural infection with PCV2 (Cap and Rep positive) or inoculation with a whole-virus inactivated vaccine (Cap and Rep positive) from subunit vaccine immunization (Cap-positive, Rep-negative). These comparative assays could be very useful in the control of PCV2 in pig herds.
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Wei W, Shen N, Xiao J, Tao Y, Luo Y, Angel C, Gu X, Xie Y, He R, Jing B, Peng X, Yang G. Expression Analysis and Serodiagnostic Potential of Microneme Proteins 1 and 3 in Eimeria stiedai. Genes (Basel) 2020; 11:E725. [PMID: 32610686 PMCID: PMC7397282 DOI: 10.3390/genes11070725] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 06/26/2020] [Accepted: 06/27/2020] [Indexed: 01/21/2023] Open
Abstract
Eimeria stiedai is an apicomplexan protozoan parasite that invades the liver and bile duct epithelial cells in rabbits and causes severe hepatic coccidiosis, resulting in significant economic losses in the domestic rabbit industry. Hepatic coccidiosis lacks the typical clinical symptoms and there is a lack of effective premortem tools to timely diagnose this disease. Therefore, in the present study we cloned and expressed the two microneme proteins i.e., microneme protein 1 (EsMIC1) and microneme protein 3 (EsMIC3) from E. stiedai and used them as recombinant antigens to develop a serodiagnostic method for an effective diagnosis of hepatic coccidiosis. The cDNAs encoding EsMIC1 and EsMIC3 were cloned and the mRNA expression levels of these two genes at different developmental stages of E. stiedai were determined by quantitative real-time PCR analysis (qRT-PCR). The immunoreactivity of recombinant EsMIC1 (rEsMIC1) and EsMIC3 (rEsMIC3) proteins were detected by Western blotting, and indirect enzyme-linked immunosorbent assays (ELISAs) based on these two recombinant antigens were established to evaluate their serodiagnostic potential. Our results showed that the proteins encoded by the ORFs of EsMIC1 (711 bp) and EsMIC3 (891 bp) were approximately 25.89 and 32.39 kDa in predicted molecular weight, respectively. Both EsMIC1 and EsMIC3 showed the highest mRNA expression levels in the merozoites stage of E. stiedai. Western blotting analysis revealed that both recombinant proteins were recognized by E. stiedai positive sera, and the indirect ELISAs using rEsMIC1 and rEsMIC3 were developed based on their good immunoreactivity, with 100% (48/48) sensitivity and 97.9% (47/48) specificity for rEsMIC1 with 100% (48/48) sensitivity and 100% (48/48) specificity for rEsMIC3, respectively. Moreover, rEsMIC1- and rEsMIC3-based indirect ELISA were able to detect corresponding antibodies in sera at days 6, 8, and 10 post E. stiedai infection, with the highest positive diagnostic rate (62.5% (30/48) for rEsMIC1 and 66.7% (32/48) for rEsMIC3) observed at day 10 post infection. Therefore, both EsMIC1 and EsMIC3 can be used as potential serodiagnostic candidate antigens for hepatic coccidiosis caused by E. stiedai.
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Romanelli PR, de Matos AMRN, Pinto-Ferreira F, Caldart ET, Mareze M, Matos RLN, Freire RL, Mitsuka-Breganó R, Headley SA, Minho AP, da Rocha Cavalcante AC, Okano W, Kohek Júnior I, Rodrigues RO, Navarro IT. Seroepidemiology of ovine toxoplasmosis and neosporosis in breeding rams from Rio Grande do Sul, Brazil. Transbound Emerg Dis 2020; 67 Suppl 2:208-211. [PMID: 32597025 DOI: 10.1111/tbed.13593] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This study determined the prevalence of ovine toxoplasmosis and neosporosis and the risk factors associated with the development of these diseases in breeding rams from the State of Rio Grande do Sul (RS), Southern Brazil. Serum samples (n = 1,800) from breeding rams maintained on 705 sheep farms from seven mesoregions were evaluated serologically to detect anti-IgG Toxoplasma gondii by indirect ELISA and anti-IgG Neospora caninum by the indirect immunofluorescence assay (IFA). The prevalence of T. gondii was 33.05% (595/1,800); seropositivity to N. caninum was 18.44% (332/1,800). Additionally, there was simultaneous seropositivity (8.94%;161/1,800) to N. caninum and T. gondii. The variables size of the property (<500 ha) (Prevalence Ratio, PR = 1.36); breeding system (semi-intensive/intensive) (PR = 1.23); and natural mounting without control (PR = 1.50) were considered as risk factors for the occurrence of T. gondii. Size of the property (<500 ha) (PR = 1.58) and natural mounting without control (PR = 2.32) were risk factors associated with the prevalence of N. caninum in rams. Additionally, separation of ewes prior to parturition was considered as a protective factor for the occurrence of T. gondii (PR = 0.82) and N. caninum (PR = 0.74). These results demonstrated that these two parasitic disease agents are endemic in rams throughout all regions of RS.
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Wang Z, Shi Y, Wang Y, Zhao L, Cui X, Wen S, Liu H, Cui W, Chen H, Ge J. Detection of Antibodies Against Canine Circovirus in Naturally and Experimentally Infected Canines by Recombinant Capsid Enzyme-Linked Immunosorbent Assay. Front Vet Sci 2020; 7:294. [PMID: 32548131 PMCID: PMC7270207 DOI: 10.3389/fvets.2020.00294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/29/2020] [Indexed: 11/30/2022] Open
Abstract
Canine circovirus (CanineCV), a new pathogen, was found to be associated with canine hemorrhagic diarrhea, vasculitis, granulomatous lymphadenitis, and acute gastroenteritis. Although CanineCV was highly positive rate in diarrhea cases, its pathogenicity remains controversial. In this study, the seroprevalence and associated risk factors of CanineCV infection among domestic dogs in northeastern China was investigated by an indirect enzyme-linked immunosorbent assay (iELISA) based on recombinant capsid protein. Results revealed the proposed iELISA had no cross-reactivity with other related pathogens, and yielded good diagnostic values. Then, to evaluate the rCap iELISA, this study applied it to detect antibodies against CanineCV in 1,047 clinical serum samples obtained from northeastern China in 2016–2017. Results showed the positive rates in the five cities of Jilin, Liaoning, and Heilongjiang provinces ranged from 22.22 to 42.29%. Statistical analysis shows a significant difference in age between dogs <3 months old with respect to the >1-year-old dogs (p = 0.005), that is, the CanineCV infection was more frequently identified from older dogs. In the artificially infected experiment, the dogs developed seroconversion after 9 or 12 days and the main way of virus excretion was through feces. More interestingly, among the 32 ELISA-positive serum samples, 34.75% samples tested positive for the CanineCV DNA by qPCR, far higher than that in ELISA-negative serum samples (5.26%, 2/38). This report is the first to demonstrate that CanineCV infection is common in the dog population in northeastern China. The results showed obvious differences in the positive rate associated with diarrhea, age, but not with different cities. This study also provide basis for evaluating the pathogenic potential of CanineCV. But, the pathogenicity, the relationship between antibody level and immune protection, and the harmful effects of this virus remain to be established.
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Wanganurakkul S, Smith DR, Chintapitaksakul L, Assavalapsakul W. Effective production of recombinant Δ60VP1 chicken anemia virus protein in Escherichia coli and its application to a serodiagnostic indirect ELISA. J Virol Methods 2020; 282:113887. [PMID: 32445874 DOI: 10.1016/j.jviromet.2020.113887] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/05/2020] [Accepted: 05/17/2020] [Indexed: 01/01/2023]
Abstract
Chicken anemia virus (CAV) causes severe anemia and immunosuppression in chickens. VP1 is the main capsid protein, and is suitable for diagnostic kit development, however, it has 24 arginine residues in the first forty N-terminal amino acids of the protein causing toxicity to bacteria leading to reduced prokaryotic expression. In this study, a 60 amino acid N-terminally truncated VP1 (Δ60VP1) which removes the toxic region was expressed in Escherichia coli and the resultant insoluble recombinant protein was purified by Ni-NTA affinity chromatography with anionic denaturing detergents. The high amounts of purified Δ60VP1 produced (150 mg/L) retained appropriate antigenicity and the antigen was used to develop an indirect enzyme-linked immunosorbent assay (ELISA) for serological diagnosis of CAV. One hundred fifty-two chicken serum samples (n = 152) were evaluated using the newly developed Δ60VP1 indirect ELISA (cutoff value = 7.58 % S/P). The sensitivity and specificity of the Δ60VP1 indirect ELISA were 87.50 % and 95.31 %, respectively, while the agreement between the Δ60VP1 indirect ELISA and the commercial IDEXX CAV ELISA was 90.79 % (kappa = 0.814). In this study, we have developed an alternative VP1 production platform in E. coli by truncating the N-terminal 60 amino acids (Δ60VP1) and using anionic denaturing detergents during the purification to successfully solubilize the insoluble Δ60VP1. The antigen was purified with high yield and good immunoreactivity, and an indirect ELISA was developed. The assay could potentially be applied to large-scale CAV serosurveillance.
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Liang Y, Song H, Wu M, Xie Y, Gu X, He R, Lai W, Jing B, Peng X, Yang G. Preliminary Evaluation of Recombinant EPC1 and TPx for Serological Diagnosis of Animal Cystic Echinococcosis. Front Cell Infect Microbiol 2020; 10:177. [PMID: 32426296 PMCID: PMC7203340 DOI: 10.3389/fcimb.2020.00177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/03/2020] [Indexed: 11/13/2022] Open
Abstract
Animal cystic echinococcosis (CE) is one of the most important helminthic diseases and affects many mammalian intermediate hosts. Practical and effective diagnosis is crucial for animal CE control. Two different recombinant antigens derived from Echinococcus granulosus, Echinococcus protoscolex calcium binding protein 1 (rEg-EPC1) and thioredoxin peroxidase (rEg-TPx), were evaluated in this study to detect the specific immunoglobulin G (IgG) in sheep and goat with CE by the indirect enzyme-linked immunosorbent assays. The diagnostic effect of the above-listed proteins was determined to their sensitivity and specificity and compared with hydatid cyst fluid, two previously reported immunogenic recombinant proteins (dihydrofolate reductase and P29), and two commercial kits available in China. Of these, the best diagnostic results were obtained in the anti-TPx IgG ELISA, with 92.6% sensitivity, 98.8% specificity, and no cross-reactivity with anti-Eg95 IgG. Recombinant E. granulosus thioredoxin peroxidase shows good potential for serological diagnosis of animal cystic echinococcosis.
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Panadero R, López CM, Remesar S, Cabanelas E, Varas G, Markina F, Díaz P, García-Dios D, Prieto A, Fernández G, Díez-Baños P, Morrondo P. Temporal and spatial spread of Hypoderma actaeon infection in roe deer from peninsular Spain determined by an indirect enzyme-linked immunosorbent assay. MEDICAL AND VETERINARY ENTOMOLOGY 2020; 34:44-48. [PMID: 31444796 DOI: 10.1111/mve.12404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/05/2019] [Accepted: 08/06/2019] [Indexed: 06/10/2023]
Abstract
The host switching of Hypoderma actaeon (Diptera: Oestridae), a specific parasite of red deer (Cervus elaphus), towards roe deer (Capreolus capreolus) has been recently reported in Spain. To provide information about the temporal and spatial spreading of H. actaeon infection in roe deer, 244 serum samples from animals hunted in Spain between 2013 and 2018 were analysed by an indirect enzyme-linked immunosorbent assay. The overall seropositivity was 13.9%. Seropositivity was higher in continental (27.7%) and mountainous (12%) areas from central Spain, followed by southern-Mediterranean (11.2%) and northern-oceanic regions (3.5%). Differences were significant between central-continental and northern-oceanic regions (P = 0.003). No differences were found according to the sex and age of roe deer (P > 0.05). In 2013, all seropositive animals were concentrated in two distant areas in central and southern Spain, suggesting that the host switch could have occurred independently in both regions. Changes in the pattern of distribution of red deer and roe deer could have favoured the spreading of this myiasis towards roe deer, indicating that roe deer may become infested by H. actaeon in areas where both cervids coexist at high densities.
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Tan Y, Dong G, Niu J, Guo Y, Yi S, Sun M, Wang K, Hu G. Development of an indirect ELISA based on glycoprotein B gene for detecting of Feline herpesvirus type 1. Pol J Vet Sci 2020; 22:631-633. [PMID: 31560479 DOI: 10.24425/pjvs.2019.129971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The study was aimed to develop an indirect enzyme-linked immunosorbent assay (ELISA), which can detect specifically Feline herpesvirus type 1 (FHV-1). The primers were designed based on the conserved sequence of FHV-1 glycoprotein B gene. The recombinant protein with reactogenicity was purified as coating antigen of the assay. The indirect ELISA, characterized by high sensitivity showed no cross-reaction with two types of feline virus, had detection limit at 1:2000 dilution. The positive rate of the assay, according to the determined cutoff value (0.25), was basically consistent with Feline Herpes Virus Antibody ELISA kit. In conclusion, the indirect ELISA with high repeatability and reproducibility can be used for detecting FHV-1, and can provide necessary support to related research.
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Böröcz K, Csizmadia Z, Markovics Á, Farkas N, Najbauer J, Berki T, Németh P. Application of a fast and cost-effective 'three-in-one' MMR ELISA as a tool for surveying anti-MMR humoral immunity: the Hungarian experience. Epidemiol Infect 2020; 148:e17. [PMID: 32014073 PMCID: PMC7019553 DOI: 10.1017/s0950268819002280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/30/2019] [Accepted: 12/18/2019] [Indexed: 12/27/2022] Open
Abstract
In Hungary, between February 2017 and July 2019, 70 confirmed measles cases were reported, raising questions about the adequacy of population-level immunity. Although the assumed vaccination coverage is ≥99%, in a recent study, we detected potential gaps in the anti-measles humoral immunity. In Hungary, according to a decree by the Ministry of Public Welfare, beginning from 2021, the healthcare provider should conduct a serosurvey of anti-measles protection levels of healthcare professionals. To facilitate the compliance with this requirement, we developed a quick 'three-in-one' or 'triple' MMR (measles, mumps and rubella) indirect ELISA (IgG); an assay format that is currently not available commercially. High throughput applicability of the 'three-in-one' ELISA was verified using 1736 sera from routine laboratory residual samples, using an automated platform (Siemens BEP 2000 Advance). Assay verification was performed by comparing the full antigen repertoire-based 'target' assay with in-house 'control' assays using recombinant viral antigen coatings, and by validated commercially available kits. Indirect immunofluorescence was used as an independent reference method. Data were analysed using OriginLab, IBM SPSS, RStudio and MedCalc. In case of measles, we combined our current results with previously published data (Ntotal measles = 3523). Evaluation of anti-mumps and anti-rubella humoral antibody levels was based on the measurement of 1736 samples. The lowest anti-measles seropositivity (79.3%) was detected in sera of individuals vaccinated between 1978 and 1987. Considering the antigen-specific seropositivity ratios of all samples measured, anti-measles, -mumps and -rubella IgG antibody titres were adequate in 89.84%, 91.82% and 92.28%, respectively. Based on the virus-specific herd immunity threshold (HIT) values (HITMeasles = 92-95%, HITMumps = 75-86%, HITRubella = 83-86), it can be stated that regarding anti-measles immunity, certain age clusters of the population may have inadequate levels of humoral immunity. Despite the potential gaps in herd immunity, the use of MMR vaccine remains an effective and low-cost approach for the prevention of measles, mumps and rubella infections.
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Zhang S, Yang J, Wang Z, Chen L, Diao Y, Tang Y. Research Note: Development of an ELISA to distinguish between goose parvovirus infection and vaccine immunization antibodies. Poult Sci 2020; 99:1332-1340. [PMID: 32111309 PMCID: PMC7587739 DOI: 10.1016/j.psj.2019.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 09/06/2019] [Indexed: 11/30/2022] Open
Abstract
Goose parvovirus (GPV) leads to a huge loss in the poultry industry, and early diagnosis is required to prevent the disease from spreading. At present, there are a variety of detection methods for GPV infection, and the ELISA method has the advantages of simple and rapid operation. However, most ELISA methods for detecting GPV can only detect the antibody level of the sample, but cannot distinguish between the GPV infection and vaccine immunization antibodies. Therefore, this study has a wider application value by establishing the detection method based on the structure and non-structural protein of the virus. The GPV non-structural (NS1) and structure (VP3) fusion proteins were used as coating antigens to establish 2 indirect ELISA methods, and the detection conditions were optimized. A series of experiments proved that the detection method has good specificity, sensitivity, and repeatability. The test results of 120 immune sera samples and 145 natural infection serum samples showed that the positive rates of immunized serum were 9.17% (NS1) and 88.33% (VP3), and the positive rates of natural infection were 88.97% (NS1) and 86.21% (VP3), which distinguish between the GPV infection and vaccine immunization antibodies. The establishment of 2 indirect ELISA methods using NS1 and VP3 proteins as inclusion antigens provides a new method for detecting GPV infection and inactivated immune antibodies, which lays a foundation for the serological diagnosis and epidemiological monitoring of GPV.
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Development and Potential Application of Ras Domain Containing Protein from Haemonchus contortus for Diagnosis of Goat Infection. Animals (Basel) 2020; 10:ani10010138. [PMID: 31952259 PMCID: PMC7022636 DOI: 10.3390/ani10010138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 01/05/2020] [Accepted: 01/10/2020] [Indexed: 02/07/2023] Open
Abstract
Haemonchus contortus is an important gastrointestinal nematode of small ruminants that causes significant mortality in goats worldwide. Diagnosis of this infection mainly depends on the evaluation of clinical signs and fecal examination. However, limitations often occur in early or mild infections. For this purpose, serological diagnosis seems to be more accurate and reliable. Ras domain-containing protein (Ras) is one of H. contortus's excretory and secretory products (ESPs) that can be isolated from different larval stages of the nematode. In this study, the recombinant H. contortus Ras domain-containing protein (rHcRas) was expressed and purified and its diagnostic potential was evaluated. Reactions between rHcRas and goat sera were tested using Western blotting (WB). The results showed that rHcRas could be recognized by sera as early as 14 days post infection (DPI), and antibodies against rHcRas in infected goats could be maintained for over 89 days. No reaction was found between rHcRas and antibodies against Trichinella spiralis, Fasciola hepatica, or Toxoplasma gondii. An indirect enzyme-linked immunosorbent assay (ELISA) was produced based on rHcRas. The optimal coating antigen (157 ng of rHcRas/well) and serum dilutions (1:50) were determined via checkerboard titration. Indirect ELISA based on rHcRas showed 87.5% sensitivity and 90.6% specificity. The cut-off values for this experiment were determined to be 0.324 (positive) and 0.273 (negative), respectively, and the variation coefficient (CV) was less than 15%. The results of the indirect ELISA in-field examination showed that 17.6% (9/51) of the goats were infected with H. contortus, higher than the fecal examination results (15.7%, 8/51). When compared the results of the indirect ELISA and necropsy testing, 98.0% (50/51) consistency was found. These results indicated that rHcRas was a potential antigen for the diagnosis of H. contortus infection in goats.
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Adhesion-Regulating Molecule from Haemonchus contortus: Potential Antigen for Diagnosis of Early Infection in Goats. Pathogens 2019; 9:pathogens9010034. [PMID: 31905914 PMCID: PMC7168579 DOI: 10.3390/pathogens9010034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/22/2019] [Accepted: 12/27/2019] [Indexed: 11/16/2022] Open
Abstract
Haemonchus contortus, a blood-sucking nematode of ruminants, causes large economic losses worldwide. Diagnosis of infection mainly depends on the evaluation of clinical signs and fecal examination. However, this has limitations for the diagnosis of early or light infections, where serological diagnosis seems to be more accurate and reliable. In this study, the recombinant H. contortus adhesion-regulating molecule protein (rHCADRM) was expressed and purified, and its diagnostic potential was evaluated. Serum samples from goats experimentally infected with H. contortus (n = 5) were collected at 0 (before infection, negative control), 7, 14, 21, 35, 49, 63, 85, and 103 days post-infection (DPI). The reactions between rHcADRM and goat serum were tested using Western blot (WB) analysis. The results show that rHcADRM can be recognized in the serum as early as 14 DPI, and the antibody against rHcADRM in infected goat could be maintained for over 89 days. No reaction was found between rHcADRM and antibodies against Trichinella spiralis, Fasciola hepatica, or Toxoplasma gondii. An indirect enzyme-linked immune sorbent assay (ELISA) was developed based on rHcADRM. The optimal coating antigen (279 ng of rHcADRM/well) and serum dilutions (1:50) were determined by checkerboard titration. A total of 64 serum samples, including 32 from H. contortus infection goats and 32 from helminth-free goats, were used to determine the positive (0.362) and negative (0.306) cut-off values for the ELISA. The results show this serological diagnosis method is highly sensitive (90.6%) and specific (93.75%). The coefficient of variation within run and between runs was less than 11%. To apply this indirect ELISA during field examination, 51 serum samples were randomly collected from goat farms and tested using this method. The result showed that 19.6% (10/51) of goats were infected with H. contortus, which was 100% consistent with the necropsy result, higher than that of fecal examination (15.7%, 8/51). These results indicate that rHcADRM could be a potential antigen for diagnosis of H. contortus infection in goats.
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