Identification of bovine tuberculosis biomarkers to detect tuberculin skin test and IFNã release assay false negative cattle.

KLEPP, LAURA; EIRIN, MARIA EMILIA; GARBACCIO, S.; SORIA, MARIO; BIGI, F.; BLANCO, FEDERICO

RESEARCH IN VETERINARY SCIENCE

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2019

0034-5288

Bovine tuberculosis (bTB) is an important animal and zoonotic disease, which causes severe economic losses. ThemainfocusofthisstudywastoassessthepredictivepowerofpreviouslyidentifiedbiomarkersofbTBin infectedanimalsthatwerenegativetothetuberculinskintest(TST).Westudied16animalswithbTB,inwhich the disease was confirmed by necropsy, and 16healthy animals. The level of expression of ten biomarkers (CXCL9, THBS1, MMP9, IL-22, CXCL10, IFNã,IL-17, FYVE, CD14, IL-1R) was evaluated by RT-qPCR upon stimulation or not of peripheral blood mononuclear cells with PPDb (purified protein derivative of bovine tuberculin).Inthisassay,CXCL9,THBS1,MMP9,IL-22andIFNãchangedtheirexpressionleveldependingonthe bTB status. In addition, we evaluated different biomarker candidates simultaneously to infer the animal condition.Byperformingananalysiswithclassificationtrees,wefoundthatthesturdiestcombinationwasIL-22, IFNã and IL-1R. On the other hand, CXCL10, IFNã and IL-22´s expression distinguished between bTB positive animalsthatwerenegativetoTST(TSTfalsenegativeanimals)andthebTBnegativegroups.Thus,thesebiomarkers are promising candidates to be tested as an ancillary diagnostic assay. In addition, the expression of CXCL10andIL-22exhibitedalsosignificantdifferencesbetweenthebTBpositiveanimalsthatwereundetectable byIFNãreleaseassay(IGRA)andTSTtests(TSTandIGRAfalsenegativeanimals)andthebTBnegativegroups. Therefore,CXCL10andIL-22constitutecandidatebiomarkersthatcouldcomplementthetwomostwidelyused diagnostictests.