Simultaneous Measurement of Antigen-Stimulated Interleukin-1β and Gamma Interferon Production Enhances Test Sensitivity for the Detection of Mycobacterium bovis Infection in Cattle

Abstract

In order to identify cytokines that may be useful as candidates for inclusion in diagnostic tests for Mycobacterium bovis infection in cattle, we compared the levels of gamma interferon (IFN-␥), interleukin 1␤ (IL-1␤), IL-4, IL-10, IL-12, macrophage inflammatory protein 1␤ (MIP-1␤), and tumor necrosis factor alpha (TNF-␣) in whole-blood cultures from tuberculosis (TB) reactor animals or TB-free controls following stimulation with M. bovis-specific antigens (purified protein derivative from M. bovis [PPD-B] or ESAT-6/CFP-10). In addition to IFN-␥ responses, the production of IL-1␤ and TNF-␣ was also statistically significantly elevated in TB reactor cattle over that in uninfected controls following stimulation with PPD-B or ESAT-6/CFP-10 peptides. Thus, we evaluated whether the use of these two additional readouts could disclose further animals not detected by measuring IFN-␥ alone. To this end, receiver operating characteristic (ROC) analyses were performed to define diagnostic cutoffs for positivity for TNF-␣ and IL-1␤. These results revealed that for ESAT-6/CFP-10-induced responses, the use of all three readouts (IFN-␥, TNF-␣, and IL-1␤) in parallel increased the sensitivity of detection of M. bovis-infected animals by 11% but also resulted in a specificity decrease of 14%. However, applying only IFN-␥ and IL-1␤ in parallel resulted in a 5% increase in sensitivity without the corresponding loss of specificity. The results for PPD-B-induced responses were similar, although the loss of specificity was more pronounced, even when only IFN-␥ and IL-1␤ were used as readout systems.In conclusion, we have demonstrated that the use of an additional readout system, such as IL-1␤, can potentially complement IFN-␥ by increasing overall test sensitivity for the detection of M. bovis infection in cattle.

Immune Responses of Bison and Efficacy after Booster Vaccination with Brucella abortus Strain RB51

“…This cytokine contributes to bacterial clearance by promoting phagolysosomal maturation (15), and the downregulation of IL-1␤ appears to be an important mechanism used by many pathogenic intracellular bacteria, including Mycobacterium tuberculosis (16). Adaptive immunity may also include increases in the expression of IL-1␤, as cattle infected with Mycobacterium bovis demonstrate increased expression of IL-1␤ in whole-blood cultures in response to incubation with M. bovis antigens (17). In the present study, it was surprising that protein expression and gene transcription of IL-1␤ did not correlate in some sampling times, whereas IFN-␥ demonstrated consistent increases in both gene transcription and protein expression after the initial and booster vaccinations.…”

Interleukin-17A as a Biomarker for Bovine Tuberculosis

“…While TSTs are the mainstays for bovine TB antemortem testing, blood-based tests are attractive, as they require only a single visit to the farm, provide the opportunity for immediate repeat testing, and yield results that are less subjective than those of TSTs. Additional biomarkers have recently emerged as potential candidates for use in blood-based TB tests for humans (reviewed by Walzl et al [5] and Salgame et al [6]) and cattle, including interleukin-1␤ (IL-1␤), IL-2, tumor necrosis factor alpha (TNF-␣), nitric oxide, IL-17, and IFN-␥-induced protein 10 (IP-10) (7)(8)(9)(10)(11)(12)(13). Of these, IL-17 is particularly appealing as a biomarker for bovine TB, as IL-17A mRNA responses determined using real-time quantitative PCR (RT-qPCR) may be predictive of both vaccine efficacy (11,14,15) and lesion severity (7) when measured after vaccination and infection, respectively.…”

Evaluation of Gamma Interferon (IFN-γ)-Induced Protein 10 Responses for Detection of Cattle Infected with Mycobacterium bovis: Comparisons to IFN-γ Responses

“…Such tests include the Quantiferon-TB Gold in-tube test (Cellestis Limited, Melbourne, Australia) and T-SPOT.TB (Oxford Immunotech, Oxfordshire, United Kingdom) for humans and Bovigam (Prionics Ag, Schlieren, Switzerland) for cattle. Additional biomarkers have recently emerged as potential candidates for evaluation in antemortem TB tests for humans (reviewed by Walzl et al [31]) and cattle (e.g., interleukin-1␤ [IL-1␤], tumor necrosis factor alpha [TNF-␣], nitric oxide, and IL-17 [5,11,30,32]). Of these candidates, the monocyte-derived chemokine IFN-␥-induced protein 10 (IP-10) (also termed CXCL10) has shown particular promise (18)(19)(20).…”