A defined antigen skin test for the diagnosis of bovine tuberculosis

Abstract

Bovine tuberculosis (bTB) is a major zoonotic disease of cattle that is endemic in much of the world, limiting livestock productivity and representing a global public health threat. Because the standard tuberculin skin test precludes implementation of Bacille Calmette-Guérin (BCG) vaccine–based control programs, we here developed and evaluated a novel peptide-based defined antigen skin test (DST) to diagnose bTB and to differentiate infected from vaccinated animals (DIVA). The results, in laboratory assays and in experimentally or naturally infected animals, demonstrate that the peptide-based DST provides DIVA capability and equal or superior performance over the extant standard tuberculin surveillance test. Together with the ease of chemical synthesis, quality control, and lower burden for regulatory approval compared with recombinant antigens, the results of our studies show that the DST considerably improves a century-old standard and enables the development and implementation of critically needed surveillance and vaccination programs to accelerate bTB control.

Evaluation of P22 Antigenic Complex for the Immuno-Diagnosis of Tuberculosis in BCG Vaccinated and Unvaccinated Goats

“…Concerning the use of the ST in solitary, the P22-based STs showed lower Se compared to both the SIT and the SICCT tests, although previous studies in dairy goat flocks, with larger samples and different epidemiological situations, have shown lower Se for SIT (65%, 95% CI: 63.3–68.2) ( 8 ) and SICCT (44.5%, 95% CI: 35–55) ( 42 ). However, the Se of the cP22-ST (74%, 95% CI: 63–83) was similar to Se observed in two previous studies using DIVA STs (based on the peptide cocktails ESAT-6, CFP-10, and Rv3616c) developed for the diagnosis of TB in cattle: 76%, 95% CI: 59–93 ( 43 ) and 75%, 95% CI: 47.7–97.7 ( 44 ). In the latter, the addition of the Rv3020c peptide improved the Se to reach 87.5% (95% CI: 61.7–98.5), being similar to the Se of sP22-ST (87%, 95% CI: 74–94) obtained in the present study.…”

A Defined Antigen Skin Test That Enables Implementation of BCG Vaccination for Control of Bovine Tuberculosis: Proof of Concept

“…However, the specificity of DST in BCG-vaccinated animals in skin tests, in bTB endemic settings, was unknown. The results of the current investigation considerably extend the prior observation of specificity of DST in BCG-vaccinated cattle in IGRA by now establishing the specificity of the DST as a skin test reagent in BCG-vaccinated and vaccine naïve calves, which is essential if DST were to be used as a DIVA diagnostic in field settings (16).…”

“…We recently developed a synthetic peptide-based DST (representing ESAT-6, CFP-10 and Rv3615c) and demonstrated its considerable sensitivity in reliably detecting M. bovis-infected animals in skin tests and in in vitro assays, while also maintaining high specificity in naïve controls (16). However, the specificity of DST in BCG-vaccinated animals in skin tests, in bTB endemic settings, was unknown.…”

“…Genomic and transcriptomic analyses have identified ESAT-6, CFP10, and Rv3615c as promising antigens for differential diagnosis of bTB (14,15). Recently, a novel defined antigen skin test (DST) consisting of peptides representing these three antigens has shown particular promise as a specific and sensitive test for the detection of bTB-infected animals in both experimental and field settings (16). While the specificity of this assay as a skin test in naïve bTB-free control animals was also previously determined, the specificity in BCG-vaccinated animals in field settings is unknown.…”

Next‐generation Theranostics: Functionalized Nanomaterials Enable Efficient Diagnosis and Therapy of Tuberculosis

“…[1] The World Health Organization (WHO) reported that there were nearly 10.4 million new cases of and 1.7 million deaths caused by TB in 2016, making it one of the most pernicious diseases. [2] Even though tremendous efforts, such as the exploitation of effective drugs [3][4][5] and development of advanced diagnostic methods, [6][7][8][9] have been implemented to combat TB in most countries, the rate of morbidity and mortality have decreased by only 2% and 3% per year, respectively. [2] DOI: 10.1002/adtp.201900189…”