Tuberculin Skin Testing Boosts Interferon Gamma Responses to DIVA Reagents in Mycobacterium bovis-Infected Cattle.
Mycobacterium bovisBCG vaccination sensitizes cattle to bovine tuberculin, which compromises the use of the current bovine tuberculosis (TB) surveillance tests. Although the performance of a blood test (that utilizes antigens expressed byMycobacterium bovisbut not by BCG) capable of discriminating infected from vaccinated animals (DIVA interferon gamma test [DIT]) has been evaluated in naturally infected TB field reactors, there is a need to perform similar analysis in a BCG-vaccinatedM. bovis-infected population. Furthermore, we explored different scenarios under which a DIT may be implemented alongside BCG vaccination: (i) serial testing to resolve potential false-positive skin test results or (ii) a standalone test to replace the single intradermal comparative cervical tuberculin (SICCT) skin test. Our results demonstrated significantly better relative test sensitivity when the DIT was evaluated in a serial test scenario. Direct comparison of pre- and post-skin test blood samples revealed that the SICCT test induced significant boosting of the gamma interferon response inM. bovis-infected animals to both the ESAT-6-CFP-10 and Rv3615c peptide cocktails that comprise the DIT, which persisted for the ESAT-6-CFP-10 reagent for at least 14 days. Importantly, no similar boosting effects were observed in noninfected BCG vaccinates, suggesting that DIVA blood testing after a recent skin test would have minimal impact on test specificity.
TB Immunology and Vaccinology, Department of Bacteriology, Animal and Plant Health Agency, New Haw, Addlestone, Surrey, United Kingdom Gareth.Jones@apha.gsi.gov.uk.
Gareth J
GJ
Jones
TB Immunology and Vaccinology, Department of Bacteriology, Animal and Plant Health Agency, New Haw, Addlestone, Surrey, United Kingdom.
Mick
M
Coad
TB Immunology and Vaccinology, Department of Bacteriology, Animal and Plant Health Agency, New Haw, Addlestone, Surrey, United Kingdom.
Bhagwati
B
Khatri
AEVA-SERVET S.L., Madrid, Spain.|Centro de Vigilancia Sanitaria Veterinaria (VISAVET), Universidad Complutense, Madrid, Spain.
Javier
J
Bezos
AgResearch, Hopkirk Research Institute, Palmerston North, New Zealand.
Natalie A
NA
Parlane
AgResearch, Hopkirk Research Institute, Palmerston North, New Zealand.
Bryce M
BM
Buddle
TB Immunology and Vaccinology, Department of Bacteriology, Animal and Plant Health Agency, New Haw, Addlestone, Surrey, United Kingdom.
Bernardo
B
Villarreal-Ramos
TB Immunology and Vaccinology, Department of Bacteriology, Animal and Plant Health Agency, New Haw, Addlestone, Surrey, United Kingdom.
R Glyn
RG
Hewinson
TB Immunology and Vaccinology, Department of Bacteriology, Animal and Plant Health Agency, New Haw, Addlestone, Surrey, United Kingdom.
H Martin
HM
Vordermeier
D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001500:BCG Vaccine / Q000276:immunology; D002417:Cattle; D009163:Mycobacterium bovis; D014374:Tuberculin Test / Q000379:methods*; D014380:Tuberculosis, Bovine / Q000276:immunology* / Q000517:prevention & control
D000942:Antigens, Bacterial; D001500:BCG Vaccine
DIVA; Mycobacterium bovis; blood test; bovine tuberculosis; gamma interferon; tuberculin skin test