scholarly journals Evaluation of a Commercially Available Recombinant-Protein Enzyme-Linked Immunosorbent Assay for Detection of Antibodies Produced in Scrub Typhus Rickettsial Infections

2000 ◽  
Vol 38 (7) ◽  
pp. 2701-2705 ◽  
Author(s):  
Meagan V. Land ◽  
Wei-Mei Ching ◽  
Gregory A. Dasch ◽  
Zhiwen Zhang ◽  
Daryl J. Kelly ◽  
...  

The 56-kDa major outer membrane protein antigen of Orientia tsutsugamuchi is the immunodominant antigen in human scrub typhus (ST) infections. An enzyme-linked immunosorbent assay (ELISA) using a recombinant 56-kDa protein (r56) to detect specific immunoglobulin M (IgM) produced in ST infections was developed, and its performance was evaluated using sera from patients with active ST (n = 59), spotted fever (SF) (n = 31), and murine typhus (MT) (n = 6) and from those without rickettsial infection (n = 52). The r56 ELISA was compared to an ELISA using native whole cell lysate ofO. tsutsugamushi Karp or O. tsutsugamushiGilliam as antigens. The performance of the assays using r56 was similar to that of those using native antigens. Using indirect immunoperoxidase (IIP) as the reference test, sensitivities were 86, 88, and 88% while specificities were 84, 90, and 87% in the three assays. Furthermore, cross-reactivity in confirmed cases of SF and MT was low (5.4, 2.7, and 2.7% respectively). The additional use of IgG in the r56 ELISA gave improved performance (sensitivity, 80%; specificity, 96%; cross-reactivity in SF and MT, 2.7%). The detection of high levels of IgG in some IgM-negative patients illustrates the importance of including a test for IgG in the detection of secondary or reactivated infections, since many of these patients were from regions in Thailand where these infections are endemic.

2003 ◽  
Vol 10 (3) ◽  
pp. 394-398 ◽  
Author(s):  
Won-Jong Jang ◽  
Myung-Suk Huh ◽  
Kyung-Hee Park ◽  
Myung-Sik Choi ◽  
Ik-Sang Kim

ABSTRACT To differentiate scrub typhus from other acute febrile diseases, a rapid and reliable serological diagnosis is important. We developed an immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) for diagnosis of recent Orientia tsutsugamushi infections in humans. The 56-kDa major outer membrane protein of O. tsutsugamushi is well known as the most immunodominant antigen in scrub typhus. The test is based on the use of the biotinylated recombinant 56-kDa protein of O. tsutsugamushi Boryong, Bor56, which was expressed as a fusion protein with a maltose-binding protein in Escherichia coli. In the test, the serum IgM antibodies were captured by anti-human IgM antibodies coated onto a microtiter plate. The captured IgM antibodies were revealed through sequential addition of biotinylated Bor56 antigen and peroxidase-conjugated streptavidin to the plate. The IgM capture ELISA was compared with the immunofluorescence antibody assay (IFA) by testing 176 serum samples from patients with diagnosed cases of rickettsial disease and patients with other acute febrile diseases. Of the 81 IgG IFA-positive samples, 78 tested positive (sensitivity, 96.3%) and all 31 IgM IFA-positive samples tested positive (sensitivity, 100%) by the IgM capture ELISA. The specificity of the IgM capture ELISA was 99%, and 1 of the 95 IFA-negative samples was positive in the assay. These results strongly suggest that IgM capture ELISA using the recombinant Bor56 antigen is a reliable and detailed method for the detection of early O. tsutsugamushi infection.


1979 ◽  
Vol 9 (1) ◽  
pp. 38-48 ◽  
Author(s):  
G A Dasch ◽  
S Halle ◽  
A L Bourgeois

A microtiter enzyme-linked immunosorbent assay (ELISA) has been developed for the titration of antibodies against scrub typhus in human and animal sera. Scrub typhus rickettsiae were grown in monolayers of irradiated mouse LM3 cells and separated from host cell materials by differential centrifugation, filtration through a glass filter (AP-20, Millipore Corp.), and isopycnic banding in Renografin density gradients. The scrub typhus ELISA antigens were obtained from the purified viable rickettsiae by French pressure cell disruption and addition of 0.2% Formalin to the soluble extract. Antisera prepared in rabbits against the prototype Karp, the Kato, and the Gilliam strains of scrub typhus were used to standardize the ELISA and to compare its sensitivity and specificity to that of the indirect fluorescent antibody test (IFA). ELISA titers were measured as the greatest serum dilution showing an optical density 0.25 above controls or by the optical density achieved at a fixed serum dilution. The IFA and ELISA end point titers were quite similar, and all three measures of titer had comparable specificity for the strains of scrub typhus. No cross-reactions between the typhus and scrub typhus wera were observed by ELISA. Both the immunoglobulin M (IgM) and IgG antibody titers of 12 sequential sera from four patients with scrub typhus were obtained by IFA and ELISA. The IFA and ELISA end point titers for IgM and IgG had correlation coefficients of 0.91 and 0.97, respectively, whereas the ELISA optical density values at a serum dilution of 1:100 had slightly lower correlations with IFA titers (0.80 and 0.94). Early rising IgM titers followed by rising IgG titers were demonstrated by ELISA in three patients with primary scrub typhus infections, whereas the IgG response predominated in a patient with a reinfection. It is concluded that the ELISA for scrub typhus is a very satisfactory alternative to the IFA test.


2006 ◽  
Vol 13 (10) ◽  
pp. 1166-1169 ◽  
Author(s):  
Stuart D. Blacksell ◽  
Lee Smythe ◽  
Rattanaphone Phetsouvanh ◽  
Michael Dohnt ◽  
Rudy Hartskeerl ◽  
...  

ABSTRACT The diagnostic utility of immunochromatographic (Leptotek) and enzyme-linked immunosorbent assay (ELISA; Panbio) tests for the detection of Leptospira immunoglobulin M antibodies was assessed in febrile adults admitted in Vientiane, Laos. Both tests demonstrated poor diagnostic accuracy using admission serum (Leptotek sensitivity of 47.3% and specificity of 75.5%: ELISA sensitivity of 60.9% and specificity of 65.6%) compared to the Leptospira “gold standard” microscopic agglutination test.


2006 ◽  
Vol 44 (9) ◽  
pp. 3432-3434 ◽  
Author(s):  
M. Giacchino ◽  
N. Chiapello ◽  
S. Bezzio ◽  
F. Fagioli ◽  
P. Saracco ◽  
...  

1986 ◽  
Vol 113 (2) ◽  
pp. 255-260 ◽  
Author(s):  
Andrzej Gardas ◽  
Kathleen L. Rives

Abstract. A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for the detection of autoantibodies reacting with thyroid plasma membrane antigens has been established. Autoantibodies reacting with thyroid plasma membrane antigens were detected by the ELISA in 95% of untreated hyperthyroid Graves', 68% of antithyroid drug-treated Graves' up to four months of the therapy, in 62% of Hashimoto's thyroiditis and in 8.9% of toxic nodular goitre. The ELISA was negative in 100% healthy blood donors, 100% non-toxic nodular goitre, in 12 patients with rheumatoid arthritis, 18 patients with scleroderma and 94% of patients with systemic lupus erythematosus. The mean value of autoantibodies titre was higher in untreated hyperthyroid Graves' (1:84 000) and lowest in positive patients with autoimmune disease of non-thyroid origin (1:4000). The cross-reactivity of antimicrosomal antigen antibodies was below 10%; there was no influence of antithyroglobulin antibodies on the ELISA; and most of the autoantibodies react with plasma membrane antigens different from the TSH binding sites.


1990 ◽  
Vol 68 (7) ◽  
pp. 1578-1588 ◽  
Author(s):  
Brian T. Luck ◽  
Colette Breuil ◽  
David L. Brown

An enzyme-linked immunosorbent assay (ELISA) was used to detect a sap-staining fungus, Ophiostoma piceae, and a biological-control agent, Gliocladium roseum, grown in liquid culture and in wood. A polyclonal serum prepared against whole cell fragments from broken mycelia of O. piceae detected O. piceae in liquid culture at 0.25 μg dry weight/mL; however, there was moderate cross-reactivity with G. roseum. Antiserum adsorbed on G. roseum had almost no reactivity with G. roseum but still reacted strongly with O. piceae. The specificity of these sera was verified, and the antigenic sites were localized, by immunogold labeling and electron microscopy. These studies confirmed that the adsorbed serum could differentiate between G. roseum and O. piceae and showed that the cell wall was the most reactive cellular component. These results are discussed in relation to the development of immunological probes for the detection of sap-staining and biological control fungi. Key words: polyclonal serum, enzyme-linked immunosorbent assay, immunogold labeling, sap-staining and biological control fungi, electron microscopy.


2021 ◽  
Vol 12 ◽  
Author(s):  
Bochao Liu ◽  
Ze Wu ◽  
Chaolan Liang ◽  
Jinhui Lu ◽  
Jinfeng Li ◽  
...  

Since December 2019, a novel coronavirus (SARS-CoV-2) has resulted in a global pandemic of coronavirus disease (COVID-19). Although viral nucleic acid test (NAT) has been applied predominantly to detect SARS-CoV-2 RNA for confirmation diagnosis of COVID-19, an urgent need for alternative, rapid, and sensitive immunoassays is required for primary screening of virus. In this study, we developed a smartphone-based nanozyme-linked immunosorbent assay (SP-NLISA) for detecting the specific nucleocapsid phosphoprotein (NP) of SARS-CoV-2 in 37 serum samples from 20 COVID-19 patients who were diagnosed by NAT previously. By using SP-NLISA, 28/37 (75.7%) serum samples were detected for NP antigens and no cross-reactivity with blood donors’ control samples collected from different areas of China. In a control assay using the conventional enzyme-linked immunosorbent assay (ELISA), only 7/37 (18.91%) serum samples were detected for NP antigens and no cross-reactivity with control samples. SP-NLISA could be used for rapid detection of SARS-CoV-2 NP antigen in primary screening of SARS-CoV-2 infected individuals.


2003 ◽  
Vol 10 (3) ◽  
pp. 439-442 ◽  
Author(s):  
F. Roodbari ◽  
M. H. Roustai ◽  
A. Mostafaie ◽  
H. Soleimanjdahi ◽  
R. Sarrami Foroshani ◽  
...  

ABSTRACT Measles is a highly contagious respiratory virus infection, with typical clinical symptoms including maculopapular rash, fever, cough, coryza, and conjunctivitis. Despite implementation of widespread vaccination programs throughout the world, the rates of global morbidity and mortality are still considerable. This study was performed to design a reliable indirect enzyme-linked immunosorbent assay (ELISA) to measure measles-specific immunoglobulin M (IgM). First, human IgM was purified, and then an anti-IgM antibody was produced in rabbits and purified in a multistep process. The rabbit IgG against human IgM was conjugated with peroxidase. Measles virus-infected Vero cells produced viral antigen. One hundred serum samples from infants of 9 to 18 months of age, mostly vaccinated, were evaluated for determining the presence of specific IgM antibodies against measles virus. The samples were also evaluated for neutralizing antibodies against measles virus by a microneutralization test (MNT). By comparing the results of the ELISA with those of MNT, it was demonstrated that ELISA had a sensitivity and specificity of 100 and 92%, respectively. On the other hand, when the results obtained by our ELISA system were compared with those of an imported measles virus IgM ELISA kit (EIAgen; Adaltis Italia SPa, Bologna, Italy), a high level of agreement was shown (k = 0.926).


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