A highly sensitive and specific time resolved fluorometric bridge assay for antibodies to HIV-1 and -2

Talha, Sheikh M.; Salminen, Teppo; Swaminathan, Sathyamangalam; Soukka, Tero; Pettersson, Kim; Khanna, Navin

doi:10.1016/j.jviromet.2011.01.001

Cited by 13 publications

(22 citation statements)

References 19 publications

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“…In our study, p39 and p55 bands were not observed in 46.87% and 16.82% of the HIV infections. Published results reported that gp160 and gp120 may be used as earlier antigens to detect the HIV antibody [28, 31–33]. In Saah et al study [28], the gpl20/160band wasdetected more early than gp41 band in HIV infectionsat the early phase,and 20 of the 23 gp41-negative cases were identifiedas havinganti-envelope antibodies (gpl20/160).…”

Section: Discussionmentioning

confidence: 99%

The characteristics of screening and confirmatory test results for HIV in Xi’an, China

et al. 2017

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ObjectivesIndividuals with recent or acute HIV infection are more infectious than those with established infection. Our objective was to analyze the characteristics of detection among HIV infections in Xi'an.MethodsA 4th-generation kit (Architect HIV Ag/Ab Combo) and three 3rd-generationEIA kits (WanTai, XinChuang and Livzon) were used for HIV screening. Overall, 665 individuals were identified as positive and were tested by western blotting (WB). The characteristics of the screening and confirmatory tests were analyzed, including the band patterns, the early detection performance and the false-positive rates.ResultsIn total, 561 of the 665 patients were confirmed as having HIV-1 infection, and no HIV-2 specific band was observed. Among these 561 WB-positive cases, reactivity to greater than or equal to 9 antigens was the most commonly observed pattern (83.18%), and the absence of reactivity to p17, p31 and gp41 was detected in 6.44%, 5.9% and 2.86% of the cases, respectively. Two cases were positive by the 4th-generation assay but negative by the 3rd-generation assay for HIV screening and had seroconversion. The false-positive rate of the Architect HIV Ag/Ab Combo (22.01%) was significantly higher than those of WanTai (9.88%), XinChuang (10.87%) and Livzon (8.93%), p<0.05.ConclusionHIV infection in Xi'an is mainly caused by HIV-1, and individuals are rarely identified at the early phase. Although the false-positive rate of the 4th-generation assay was higher than that of the 3rd-generation assay, it is still recommended for use as the initial HIV screening test for high-risk individuals. In Xi’an, a 3rd-generation assay for screening could be considered.

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Section: Discussionmentioning

confidence: 99%

The characteristics of screening and confirmatory test results for HIV in Xi’an, China

et al. 2017

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“…The r-Tp antigen, henceforth termed as Tp15-17-47, was a designer fusion antigen of three Tp membrane proteins namely, Tp15, Tp17 and Tp47, respectively, with flexible tetra-glycyl (G 4 ) residues expressing in between the three proteins. This synthetic gene was inserted into pET-32a(+) at Bam HI/ Sal I restriction sites, in-frame with the vector-encoded thioredoxin (Trx) gene and 6x-His tag encoding sequence to express r-Trx-Tp15-17-47 (henceforth termed as r-Tp15-17-47), and into pTrx-BAP vector [17], [18] in-frame with the vector encoded Trx (thioredoxin)-6x-His tag-BAP (biotin acceptor peptide) sequences at the amino terminus, to express the r-Trx-BAP-Tp15-17-47 (henceforth termed as r-Bio-Tp15-17-47) antigen. The resultant plasmids were transformed separately into E. coli BL21(DE3) cells, and induced to express with 1 mM IPTG (isopropyl-β-d-thiogalactopyranoside; Qiagen, Hilden, Germany).…”

Section: Methodsmentioning

confidence: 99%

“…The buffer of r-Tp15-17-47 was changed to 50 mM sodium carbonate buffer, pH 9.6 using Nucleic Acid Purification (NAP) Sephadex G-25 columns (GE Healthcare, Uppsala, Sweden). The coating of r-Tp15-17-47 on Eu-nanoparticles was performed essentially as described before [18]. r-Tp15-17-47 coated Eu-nanoparticles were stored in 2 mM Tris-HCl, pH 9.0 supplemented with 0.1% BSA and 0.01% sodium azide at 4°C, covered from light.…”

Section: Methodsmentioning

confidence: 99%

Europium Nanoparticle-Based High Performing Immunoassay for the Screening of Treponemal Antibodies

et al. 2013

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Treponema pallidum subspecies pallidum (Tp) is the causative agent of syphilis which mainly spreads through sexual contact, blood transfusion and perinatal route. In order to curtail the spread of the infection and to clinically manage the disease, timely, accurate and reliable diagnosis is very important. We have developed an immunoassay for the detection of treponemal antibodies in human serum or plasma samples. In vivo biotinylated and non-biotinylated versions of the recombinant antigen were designed by the fusion of three Tp-specific antigens namely Tp15, Tp17 and Tp47. These fusion antigens were expressed in E. coli and purified using single-step metal affinity chromatography. Biotinylated fusion antigen immobilized on streptavidin coated plate was used to capture the treponemal antibodies and the non-biotinylated antigen coated on europium nanoparticles was used as tracer. Assays with two different incubation times of 10 min and 1 h were developed, and following the incubation the europium fluorescence was measured using time-resolved fluorometry. The developed time-resolved fluorometric (TRF) immunoassays were evaluated with in-house and commercial serum/plasma sample panels. For well-established treponemal antibodies positive or negative samples, the sensitivity of TRF immunoassay with 10 min incubation time was 97.4%, and of TRF immunoassay with 1 h incubation time was 98.7%, and the specificities of both the TRF immunoassays were 99.2%. For the samples with discordant results with the reference assays, both the TRF immunoassays showed better specificity than the Enzygnost syphilis enzyme immunoassay as a screening test. The two different incubation times did not have any significant effect on the signal to cutoff (S/Co) ratios obtained with the two immunoassays (p = 0.06). Our results indicate that the developed immunoassay with a short incubation time of 10 min has the potential to be used in clinical laboratories and in blood-bank settings as a screening test for treponemal antibodies.

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“…Antibody screening assays relying on other methods than EIA or immunoprecipitation are currently in development, with the goal to enhance specificity and to have a higher throughput (Talha et al 2011). …”

Section: Screening Assaysmentioning

confidence: 99%

HIV-2: Testing Specificities

Ruelle¹

2012

HIV Testing

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A highly sensitive and specific time resolved fluorometric bridge assay for antibodies to HIV-1 and -2

Cited by 13 publications

References 19 publications

The characteristics of screening and confirmatory test results for HIV in Xi’an, China

The characteristics of screening and confirmatory test results for HIV in Xi’an, China

Europium Nanoparticle-Based High Performing Immunoassay for the Screening of Treponemal Antibodies

HIV-2: Testing Specificities

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