scholarly journals Evaluation of an Enzyme-Linked Immunosorbent Assay Using Recombinant Major Surface Protein 5 for Serological Diagnosis of Bovine Anaplasmosis in Venezuela

1998 ◽  
Vol 5 (2) ◽  
pp. 259-262 ◽  
Author(s):  
Armando Reyna-Bello ◽  
Axel Cloeckaert ◽  
Nieves Vizcaíno ◽  
Mary I. Gonzatti ◽  
Pedro M. Aso ◽  
...  

ABSTRACT An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the serological diagnosis of bovine anaplasmosis with purified recombinant major surface protein 5 (MSP5) of Anaplasma marginale produced in Escherichia coli. Serum antibody responses against MSP5 were detected in calves experimentally infected with A. marginale as early as 21 days postinfection and reached maximum titers at 28 days postinfection. The MSP5 ELISA performed with serum samples taken from field cattle from different regions of Venezuela showed a seroprevalence of 47%, which seems to be in accordance with the reported epidemiological status of bovine anaplasmosis in Venezuela. Positive results obtained in the MSP5 ELISA were further confirmed by immunoblotting, with the recombinant MSP5 as the antigen. Thus, these results confirmed the importance of MSP5 as a suitable antigen for the serological diagnosis of bovine anaplasmosis.

1998 ◽  
Vol 36 (3) ◽  
pp. 777-782 ◽  
Author(s):  
Susana Torioni de Echaide ◽  
Donald P. Knowles ◽  
Travis C. McGuire ◽  
Guy H. Palmer ◽  
Carlos E. Suarez ◽  
...  

A competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5 (rMSP5-cELISA) of Anaplasma marginale was validated in a naturally infected cattle herd in an area of eastern Oregon where A. marginale is endemic. The true positive and negative A. marginale infection status of 235 randomly selected cattle was determined by using a nested PCR (nPCR) coupled with msp5 sequence analysis and hybridization. Judgment of the reliability of the nPCR and hybridization for detection of persistent infections was based on three observations. First, the nPCR was able to detect as few as 30 infected erythrocytes per ml. Second, the nPCR was able to consistently detect low levels of rickettsemia in seven carrier cattle experimentally infected with A. marginale. Third, msp5sequence analysis showed >95% identity among 30 nPCR amplicons from cattle naturally infected with field strains of A. marginale. The nPCR and hybridization identified 151 infected and 84 uninfected cattle among the 235 animals tested. With a cutoff point of 28%, the rMSP5-cELISA showed a sensitivity of 96% and a specificity of 95%. These results indicate that the rMSP5-cELISA can sensitively and specifically detect cattle with naturally acquired persistent A. marginale infections and suggest that it is an excellent assay for epidemiological studies, eradication programs, and regulation of international cattle movement.


Author(s):  
J.J.N. Ngeranwa ◽  
S.P. Shompole ◽  
E.H. Venter ◽  
A. Wambugu ◽  
J.E. Crafford ◽  
...  

The seroprevalence of Anaplasma antibodies in wildlife (eland, blue wildebeest, kongoni, impala, Thomson's gazelle, Grant's gazelle, giraffe and plains zebra) and domestic animal (cattle, sheep and goat) populations was studied in wildlife / livestock interface areas of Kenya. Serum samples were analyzed by competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA), using a recombinant antigen (MSP-5) from Anaplasma marginale surface membrane. A monoclonal antibody, FC-16, was used as the primary antibody, while anti-mouse conjugated to horseradish peroxidase was used as the secondary antibody. The results indicate a high seroprevalence in both wildlife and livestock populations, in contrast to earlier reports from Kenya, which indicated a low seroprevalence. The differences are attributed to the accurate analytical method used (CI-ELISA), as compared with agglutination techniques, clinical signs and microscopy employed by the earlier workers.


2007 ◽  
Vol 14 (3) ◽  
pp. 262-268 ◽  
Author(s):  
N. I. Strik ◽  
A. R. Alleman ◽  
A. F. Barbet ◽  
H. L. Sorenson ◽  
H. L. Wamsley ◽  
...  

ABSTRACT Major surface protein 5 (Msp5) of Anaplasma marginale is highly conserved in the genus Anaplasma and the antigen used in a commercially available competitive enzyme-linked immunosorbent assay (cELISA) for serologic identification of cattle with anaplasmosis. This study analyzes the degrees of conservation of Msp5 among various isolates of Anaplasma phagocytophilum and the extent of serologic cross-reactivity between recombinant Msp5 (rMsp5) of Anaplasma marginale and A. phagocytophilum. The msp5 genes from various isolates of A. phagocytophilum were sequenced and compared. rMsp5 proteins of A. phagocytophilum and A. marginale were used separately in an indirect ELISA to detect cross-reactivity in serum samples from humans and dogs infected with A. phagocytophilum and cattle infected with A. marginale. Serum samples were also tested with a commercially available competitive ELISA that uses monoclonal antibody ANAF16C1. There were 100% sequence identities in the msp5 genes among all of the A. phagocytophilum isolates from the United States and a horse isolate from Sweden. Sheep isolates from Norway and dog isolates from Sweden were 99% identical to one another but differed in 17 base pairs from the United States isolates and the horse isolate. Serologic cross-reactivity was identified when serum samples from cattle infected with A. marginale were reacted with rMsp5 of A. phagocytophilum and when serum samples from humans and dogs infected with A. phagocytophilum were reacted with rMsp5 of A. marginale in an indirect-ELISA format. Serum samples from dogs or humans infected with A. phagocytophilum did not cross-react with rMsp5 of A. marginale when tested with the commercially available cELISA. These results suggest that rMsp5 of A. phagocytophilum is highly conserved among United States and European isolates and that serologic distinction between A. phagocytophilum and A. marginale infections cannot be accomplished if rMsp5 from either organism is used in an indirect ELISA.


2019 ◽  
Vol 32 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Macarena Sarli ◽  
Carolina S. Thompson ◽  
María B. Novoa ◽  
Beatriz S. Valentini ◽  
Mariano Mastropaolo ◽  
...  

Bovine anaplasmosis is a worldwide infectious disease caused by the intraerythrocytic bacterium Anaplasma marginale, which is transmitted by ticks and fomites. A. centrale is a less virulent subspecies used as a live vaccine in cohorts of 8- to 10-mo-old calves that did not naturally reach enzootic stability. We developed 3 variants of a double-antigen sandwich ELISA (dasELISA) using a recombinant major surface protein 5 (MSP5) from A. marginale (dasELISAm) or from A. centrale (dasELISAc) or using MSP5 from both organisms (dasELISAmc). Each dasELISA was tested for the detection of antibodies against A. marginale and A. centrale. The tests were validated using serum samples from cattle not infected with Anaplasma spp. ( n = 388), infected with A. marginale ( n = 436), and vaccinated with A. centrale ( n = 358), confirmed by nested PCR. A total of 462 samples were compared with a commercial competitive ELISA (cELISA). For dasELISAm, dasELISAc, and dasELISAmc, specificities were 98.7%, 98.7%, and 97.4%, and overall sensitivities were 92.6%, 85.7%, and 97.4%, respectively. For A. marginale–infected and A. centrale–vaccinated cattle, sensitivities were 97.7% and 86.3% for dasELISAm, and 77.7% and 95.5% for dasELISAc, respectively. Sensitivity of dasELISAmc was similar for both groups (>96%). The agreement rate between dasELISAmc and cELISA was 96.3% (κ = 0.92); the former test allowed earlier detection of seroconversion of vaccinated cattle than did cELISA. Based on these results, the test could be used to 1) determine the enzootic stability or instability of anaplasmosis in calves, 2) conduct epidemiologic studies, and 3) evaluate the immunogenicity of A. centrale live vaccine.


2000 ◽  
Vol 12 (2) ◽  
pp. 136-141 ◽  
Author(s):  
Ashok K. Singh

Serum samples from cats and pigs were analyzed by the solid-phase chemiluminescent enzyme immunoassay (SPCEI), enzyme-linked immunosorbent assay (ELISA), and indirect latex agglutination (ILA) methods. The SPCEI and ILA methods accurately analyzed Toxoplasma IgG (T-IgG) in both clinical and spiked samples from pigs and cats. The ELISA method accurately analyzed T-IgG in spiked samples from cats and pigs or clinical samples from pigs, but it did not accurately analyze T-IgG in clinical samples from cats. The antibody used in the ELISA kit did not cross-react with cat T-IgG. The SPCEI method that uses a stand-alone automated analyzer provided quantitative analysis, whereas the ELISA and ILA methods provided qualitative or, at best, semiquantitative analysis of T-IgG. The SPCEI and ELISA methods were rapid (60–90 minutes for 30 samples), whereas the ILA method required 13–15 hours for 30 samples. Although the three methods accurately distinguished positive from negative samples, the ILA method yielded many weakly positive results that were not confirmed by either the ELISA or SPCEI method. Thus, the indirect agglutination tests may give nonspecific responses at lower T-IgG concentrations.


2008 ◽  
Vol 15 (9) ◽  
pp. 1316-1321 ◽  
Author(s):  
Will L. Goff ◽  
Wendell C. Johnson ◽  
John B. Molloy ◽  
Wayne K. Jorgensen ◽  
Susan J. Waldron ◽  
...  

ABSTRACT A competitive enzyme-linked immunosorbent assay (cELISA) based on a broadly conserved, species-specific, B-cell epitope within the C terminus of Babesia bigemina rhoptry-associated protein 1a was validated for international use. Receiver operating characteristic analysis revealed 16% inhibition as the threshold for a negative result, with an associated specificity of 98.3% and sensitivity of 94.7%. Increasing the threshold to 21% increased the specificity to 100% but modestly decreased the sensitivity to 87.2%. By using 21% inhibition, the positive predictive values ranged from 90.7% (10% prevalence) to 100% (95% prevalence) and the negative predictive values ranged from 97.0% (10% prevalence) to 48.2% (95% prevalence). The assay was able to detect serum antibody as early as 7 days after intravenous inoculation. The cELISA was distributed to five different laboratories along with a reference set of 100 defined bovine serum samples, including known positive, known negative, and field samples. The pairwise concordance among the five laboratories ranged from 100% to 97%, and all kappa values were above 0.8, indicating a high degree of reliability. Overall, the cELISA appears to have the attributes necessary for international application.


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