Anti-phenolic glycolipid antibodies ininfected cattle.

, the causative agent of bovine tuberculosis (bTB), causes significant financial losses in the agricultural industry. Additionally,transmission from animals to humans can result in zoonotic TB, especially in low- and middle-income countries (LMICs), highlighting the need to enhance One Health surveillance to mitigate this threat. Antibodies directed against a major mycobacterial cell wall component of, phenolic glycolipid-I (PGL-I), have shown excellent performance in identifyinginfection in humans and animals. In this study, we therefore investigated whether antibodies againstPGL similarly represent a useful biomarker forinfection in cattle. Comparing sera from naturally-infected and the single intradermal comparative cervical tuberculin test (SICCT)-negative cattle, we assessed the potential ofPGL antibodies to identify this mycobacterial infection. Our results show that serum levels of anti-PGL IgG and -IgM in-infected cattle were significantly higher than in the SICCT-negative cattle. The sensitivity for anti-PGL IgM in infected animals was, however, moderate (44.9 %) and the false-positive rate was 6.3 % in SICCT-negative cattle. Notably, vaccination with BCG- or heat-killeddid not affect serum levels of anti-PGL IgM in cattle. Moreover, none of the 57 anti-PGL-seropositive cattle tested positive in the anti-PGL-I assay. This study shows for the first time that antiPGL antibodies can be detected in infected cattle: anti-PGL IgM is a highly specific, but moderately sensitive biomarker forinfection in cattle, showing potential for differentiate infected from vaccinated animals (DIVA). It could be a valuable component in a multi-biomarker approach for diagnosing bTB.