Early antibody responses to lipid antigens in red deer infected with Mycobacterium bovis

The problem: Early and rapid diagnosis of bovine tuberculosis remains an issue of great interest. Aim: The aim of this study was to evaluate the use of synthetic lipid antigens for diagnosis of tuberculosis in red deer ( Cervus elaphus ). The proposition: Synthetic mycolic acid derivatives, identical to components of mycobacterial cells, bind to antibodies to lipids produced in active human tuberculosis. Experimental infection studies in red deer ( Cervus elaphus ) allow the evaluation of such antigens for the serodiagnosis of bovine tuberculosis. Results: Antibody levels in plasma from deer experimentally infected with Mycobacterium bovis were evaluated in ELISA using synthetic antigens based on several classes of mycolic acid, using protein G as conjugate. All antigens gave significantly increased responses 60 days post-infection, when all animals had active disease. A significantly increased response was also observed with four antigens 15 days after infection. Conclusion: ELISA using synthetic lipid antigens not only detects antibodies in the plasma of deer experimentally infected with M. bovis , but a strong response occurs early in the infection. With a full analysis of responses with naturally infected animals, this may offer a useful supplement to current diagnostic methods. • The cells of each mycobacterium contain a characteristic complex mixture of mycolic acid derivatives. • Natural mixtures of mycolic acid derivatives bind to antibodies to lipids developed in some diseases caused by mycobacteria. • Deer experimentally infected with Mycobacterium bovis all showed disease lesions at slaughter after 60 days. • ELISA using synthetic mycolic acid derivatives detects binding to antibodies in the plasma of these animals after 60 days. • Strong antibody binding responses were seen with several synthetic antigens even 15 days after infection.