Potential for rapid antibody detection to identify tuberculous cattle with non-reactive tuberculin skin test results

Abstract

BackgroundBovine tuberculosis (TB) control programs generally rely on the tuberculin skin test (TST) for ante-mortem detection of Mycobacterium bovis-infected cattle.ResultsPresent findings demonstrate that a rapid antibody test based on Dual-Path Platform (DPP®) technology, when applied 1-3 weeks after TST, detected 9 of 11 and 34 of 52 TST non-reactive yet M. bovis-infected cattle from the US and GB, respectively. The specificity of the assay ranged from 98.9% (n = 92, US) to 96.0% (n = 50, GB) with samples from TB-free herds. Multi-antigen print immunoassay (MAPIA) revealed the presence of antibodies to multiple antigens of M. bovis in sera from TST non-reactors diagnosed with TB.ConclusionsThus, use of serologic assays in series with TST can identify a significant number of TST non-reactive tuberculous cattle for more efficient removal from TB-affected herds.

Identification of Novel Antigens Recognized by Serum Antibodies in Bovine Tuberculosis

“…bovis, including 10 polyepitope fusions developed in our previous studies on human TB serology. Serum samples were obtained from 31 cattle that had been aerosol inoculated with M. bovis strain 95-1315 or 10-7428 in four independent experiments (serially collected during infection) and from 11 tuberculous cattle with naturally acquired disease that were tuberculin skin test nonreactors (15). An emphasis was placed on antigen candidates capable of eliciting relatively early antibody responses and/or showing complementary reactivity to the Rv2875 (MPT70) and Rv2873 (MPT83) proteins, known to be predominantly recognized by antibodies in M. bovis infection (16,17).…”

“…In contrast to the intradermal tuberculin test, serology does not require multiple interventions, is much less subjective for interpretation, and does not interfere with the immune status of the tested animals. Importantly, serological assays can detect cattle with M. bovis infection that are anergic to CMI-based tests (15,18,19). Despite the attractive operational advantages of serology, numerous attempts to develop a reliable antibody test for M. bovis infection in cattle have been disappointing (9,11).…”

“…In Michigan and Texas, 11 tuberculous cattle were identified to be CFT nonreactors. Disease in these animals was confirmed by the presence of gross lesions and positive results by histopathology, mycobacterial culture, and/or IS6110 PCR, as previously described (15). The negative-control group included 51 samples obtained prior to experimental infection from cattle in the NADC studies and 40 serum samples collected from tuberculin skin test nonreactors in two TB-free herds.…”

“…The intradermal tuberculin test has suboptimal sensitivity and inconsistent performance (1, 9, 10), while the available blood-based assays, such as the Thermo Fisher Scientific Bovigam TB kit or the Idexx M. bovis antibody (Ab) test, lack the required accuracy and show a significant variability when used in different geographic areas (11-13). Given the ease of sample collection and the test procedure, antibody detection assays may be useful to identify M. bovis-infected cattle (1,14,15), but the existing methods require improvement.The primary goal of the present study was to identify novel seroreactive antigens of M. bovis. Using a multiantigen print immunoassay (MAPIA) and well-characterized serum samples serially collected from cattle with experimental or naturally acquired M. bovis infection, we screened a panel of 101 recombinant proteins of M. tuberculosis, including 10 polyepitope fusions.…”

“…The intradermal tuberculin test has suboptimal sensitivity and inconsistent performance (1, 9, 10), while the available blood-based assays, such as the Thermo Fisher Scientific Bovigam TB kit or the Idexx M. bovis antibody (Ab) test, lack the required accuracy and show a significant variability when used in different geographic areas (11-13). Given the ease of sample collection and the test procedure, antibody detection assays may be useful to identify M. bovis-infected cattle (1,14,15), but the existing methods require improvement.…”