A new recombinant F1 antigen as a cost and time-effective tool for plague diagnosis

Tavares, Diego H. C.; Bezerra, Matheus Filgueira; Magalhães, Franklin Barbalho; Cavalcanti, Thaíse Y.V.L.; Xavier, Camila Cavalcanti; Leal, Nilma Cintra; Almeida, Alzira Maria Paiva de; Reis, Christian Robson de Souza

doi:10.1016/j.mimet.2020.105903

Cited by 8 publications

(8 citation statements)

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“…While the protocol here established requires 750 ng of F1 antigen per tested sample (using triplicates), HA spends 20,000 ng of F1 per tested sample (considering the standard eight dilutions according to Chu [10], resulting in the use of approximately twenty-seven times more antigen per sample. This difference can be particularly relevant for plague diagnosis given the complexity and costs of producing and purifying F1 from extensive Y. pestis culturing in biosafety level 3 (BSL3) laboratories [23].…”

Section: Discussionmentioning

confidence: 99%

“…Sera from rabbits immunized with formol-killed Y. pestis and other pathogenic Yersinia strains (whole-cells immunization) or with the purified F1 antigen, produced as previously described [23] for positive control in routine diagnosis and were kindly provided by the SRP. From the 37 positive control sera, 14 were from rabbits exposed to the reference EV76 or A1122 Y. pestis strains in independent experiments, 18 were from rabbits exposed to diverse Brazilian Y. pestis strains from the Fiocruz-CYP (http://cyp.fiocruz.br) bacterial cultures collection and five were from rabbits exposed to the purified F1 antigen (three native F1 and two recombinant F1, expressed in E. coli) [23]. Additionally, to evaluate whether the ELISA test would present cross-reaction with other Yersiniae, five rabbits immunized with distinct isolates of Yersinia pseudotuberculosis and two with Yersinia enterocolitica were included.…”

Section: Rabbit Immunizationmentioning

confidence: 99%

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A new multi-species Protein A-ELISA assay for plague diagnosis in humans and other mammal hosts

Bezerra

Xavier

Almeida

et al. 2021

Preprint

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Background: The Hemagglutination assay (HA) is widely used in plague diagnosis, however, it has a subjective interpretation and demands high amounts of antigen and other immunobiological supplies. Conventional IgG-ELISA is limited by the need of specific conjugates for multiple plague hosts. Methods: Thus, we developed an ELISA Protein A-peroxidase method to detect anti-F1 antibodies across several species, including humans. To determine the cut-off and performance rates, HA results from 288 samples (81 rabbits, 64 humans, 66 rodents and 77 dogs) were used as reference. Results: Optimal conditions were found with 250ng/well of F1 and 1:500 serum dilution. Protein A-ELISA showed high repeatability and reproducibility. The positive/negative OD ratios were higher in Protein A-ELISA and there was no significant cross-reaction with other pathogenic yersiniae. The overall sensitivity/specificity, area under the curve and Kappa rates for Protein A-ELISA were 93.9/98.9%; 0.993 and 0.938, respectively. Similar results were observed in each species separately. There was a strong agreement between Protein A and IgG assays (kappa=0.973) in independent analysis (n=487). Conclusions: Altogether, the Protein A-ELISA showed high performance when compared both to HA and IgG-ELISA, with a polyvalent single protocol that requires reduced amounts of antigen and can be employed to any plague hosts.

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Section: Discussionmentioning

confidence: 99%

Section: Rabbit Immunizationmentioning

confidence: 99%

A new multi-species Protein A-ELISA assay for plague diagnosis in humans and other mammal hosts

Bezerra

Xavier

Almeida

et al. 2021

Preprint

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Section: Methodsmentioning

confidence: 99%

Evaluation of a multi-species Protein A-ELISA assay for plague serologic diagnosis in humans and other mammal hosts

et al. 2022

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Background The Hemagglutination assay (HA) is widely used in plague diagnosis, however, it has a subjective interpretation and demands high amounts of antigen and other immunobiological supplies. On the other hand, the conventional Anti-IgG ELISA is limited by the need of specific conjugates for multiple plague hosts, which leaves a gap for new diagnostic methods able to cover both the diagnosis of human cases and the epidemiological surveillance of multiple sentinel species. Methods We developed an ELISA Protein A-peroxidase method to detect anti-F1 antibodies across several species, including humans. To determine the cut-off and performance rates, HA results from 288 samples (81 rabbits, 64 humans, 66 rodents and 77 dogs) were used as reference. Next, we evaluated the agreement between Protein A-ELISA and Anti-IgG ELISA in an expanded sample set (n = 487). Results Optimal conditions were found with 250ng/well of F1 and 1:500 serum dilution. Protein A-ELISA showed high repeatability and reproducibility. We observed good correlation rates between the Protein A and IgG ELISAs optical densities and a higher positive/negative OD ratio for the Protein A-ELISA method. The overall sensitivity, specificity and area under the curve for Protein A-ELISA were 94%, 99% and 0.99, respectively. Similar results were observed for each species separately. In the analysis of the expanded sample set, there was a strong agreement between Protein A and IgG assays (kappa = 0.97). Furthermore, there was no cross-reaction with other common infectious diseases, such as dengue, Zika, Chagas disease, tuberculosis (humans) and ehrlichiosis, anaplasmosis and leishmaniasis (dogs). Conclusions Altogether, the Protein A-ELISA showed high performance when compared both to HA and Anti-IgG ELISA, with a polyvalent single protocol that requires reduced amounts of antigen and can be employed to any plague hosts.

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“…The 25 positive control sera were derived from rabbits immunized with formol-killed Y. pestis or with the purified F1 antigen, as previously described (Tavares et al, 2020). Three of those were from rabbits immunized with the reference EV76 or A1122 Y. pestis strains in independent experiments, 18 were immunized with diverse Brazilian Y. pestis strains from the Fiocruz-CYP bacterial culture collection maintained at the Aggeu Magalhães Institute (http://cyp.fiocruz.br), and four were immunized with the F1 antigen.…”

Section: Methodsmentioning

confidence: 99%

Performance assessment of a new indirect rapid diagnostic test for plague detection in humans and other mammalian hosts

Bezerra

Santos

Rocha

et al. 2021

Preprint

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Plague is a flea-borne zoonosis that affects a wide range of mammals and still causes outbreaks in human populations yearly across several countries. While crucial for proper treatment, early diagnosis is still a major challenge in low- and middle-income countries due to poor access to laboratory infrastructure in rural areas. To tackle this issue, we developed and evaluated a new F1-based rapid diagnostic test (RDT) as an alternative method for plague diagnosis in humans and other mammals in the field. In this study, 187 serum samples from humans, dogs, rodents and rabbits were retrospectively assessed using the Plague RDT method. To calculate its performance rates, results were confronted to those obtained by hemagglutination (HA) and ELISA, considered as the reference standards. Remarkably, the results from RDT were in full agreement with those from the ELISA and HA assays, resulting in 100% (CI 95% = 95.5-100%) of sensitivity and 100% (CI 95% = 96.6-100%) of specificity. Accordingly, the Cohens Kappa test coefficient was 1.00 (almost perfect agreement). Moreover, the RDT showed no cross-reaction when tested with sera from individuals positive to other pathogens, such as Yersinia pseudotuberculosis, Yersinia enterocolitica, Anaplasma platys, Erliquia canis and Leishmania infantum. Although preliminary, this study brings consistent proof-of-concept results with high performance rates of the Plague RDT when compared to other methods well-established in the plague routine serodiagnosis. Although further human and animal population-based studies will be necessary to validate these findings, the data presented here show that the Plague RDT is highly sensitive and specific, polyvalent to several mammal species and simple to use in field surveillance or point-of-care situations with instant results.

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A new recombinant F1 antigen as a cost and time-effective tool for plague diagnosis

Cited by 8 publications

References 10 publications

A new multi-species Protein A-ELISA assay for plague diagnosis in humans and other mammal hosts

A new multi-species Protein A-ELISA assay for plague diagnosis in humans and other mammal hosts

Evaluation of a multi-species Protein A-ELISA assay for plague serologic diagnosis in humans and other mammal hosts

Performance assessment of a new indirect rapid diagnostic test for plague detection in humans and other mammalian hosts

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