Development And Primary Application Of Indirect ELISA For Detection For Specific Antibodies Against Mycobacterium Bovis

Mycobacterium bovis is the causative agent of bovine tuberculosis (bTB) in a range of animal species and human beings. The disease is chronic and can be transmitted via respiration and ingestion. Seriously diseased cows which could exhale bacteria to the environment are the main source of infection. The disease occurs worldwide but the epidemic situation became especially serious in our country in recent years following increased incidence of drug-resistant Mycobacterium bovis and increased number of farms. The spreading of bTB caused enormous economic losses to cattle raising industry in the world, and to this day the losses from bTB is greater than the losses caused by all other bovine diseases combined. More importantly, Mycobacterium bovis can infect humans and cause seriously public health concerns. So it is imperative to prevent and control bTB. Due to the lack of an effective vaccine that could prevent the infection of bovine tuberculosis, many countries adopt the "test-and-slaugter" policy without vaccination to control bTB. So an accurate and timely diagnostic method is very important for preventing and control bTB.For the detection of bTB, tuberculin skin test (TST) is the only method recommended by world organisation for animal health (Office International Des Epizooties, OIE), but the method has serious non-specific reactions and is mostly false negative for seriously diseased cows. The protein purified derivative (PPD) used for indirect enzyme-linked immunosorbent assays (ELISA) to detect antibodies against bTB had been tried, but PPD is a protein mixture that has complex components, including many antigens shared with other Mycobacterium species besides specific antigens of Mycobacterium bovis. So the cross reaction can not be avoided. Therefore, to develop a specific and sensitive diagnostic method for bTB is an urgent task for bTB control.MPB70, MPB83, CFP10 and ESAT-6 are specific antigens of Mycobacterium bovis, and have potential to be used for diagnosis of bTB as suggested by many studies. In order to provide a method that has good specificity, sensitivity, and practicability for bTB diagnbosis in veterinary practice, we developed an indirect ELISA method using the four...