[ODP5B] b. Methods in Detection and Identification of Clinical Microbes

[ODP-093] Evaluation of IgG levels to 12 antigens in a Mycobacterium tuberculosis-infected Asian elephant

○Satoshi Ishikawa^1,2, Erina Inouchi¹, Satomi Suga², Yasuhiko Mukai², Haruka Kobayashi¹, Yuriko Ozeki¹, Akihito Nishiyama¹, Yoshitaka Tateishi¹, Sohkichi Matsumoto¹ (¹Dep. Bacteriol., Niigata Univ. Med., ²Fukuyama Zoo)

Mycobacterium tuberculosis infects wide variety of mammalian species. Especially in Asian elephants (Elephas maximus), tuberculosis (TB) had been reported worldwide, not only in captivity, but also in the wild. Sputum of them cannot be collected when needed and X-rays or CT scans are not available because of their huge body. So, how to detect and monitor the TB patients is the critical issue for elephants. In recent years, many studies had been carried out on immunological testing methods, but the examined antigens were limited. We experienced the Japanese first case of TB treatment in an elephant at Fukuyama zoo, and the sera collected over 16 years had been cryopreserved. With these sera, the IgG levels to 12 antigens were semi-quantified, and the high values to 4 antigens, PPD, ESAT6/CFP10, MPB83 and Ag85B were detected. Thus, the IgG levels against these 4 antigens were monitored longitudinally, and IgG levels of ESAT6/CFP10 were stable and high, regardless of onset and treatment. On the other hand, IgG levels of Ag85B were largely responsive to onset and treatment. And, IgG levels of PPD and MPB83 showed intermediate responses. These results suggested the immunodominanity of ESAT6/CFP10 and its usefulness to infection detection. Furthermore, Ag85B had the potential to be a new marker for elephant TB to detect the development and to monitor the treatment effectivity.