PO 8518 Latent tuberculosis infection detection by IGRA using mycobacterium tuberculosis alternative desaturase A1 immune-dominant antigen

Background Despite an efficient treatment and a widely-used vaccine, one third of the world’s population is estimated to be latently infected (LTBI) with Mycobacterium tuberculosis (Mtb) and are at risk of progressing to contagious active tuberculosis. New TB vaccines and improved detection of LTBI are therefore urgently required for global TB control. As a first step towards these goals, a better understanding of host recognition and response to immunogenic Mtb antigens is needed. Methods In this study, interferon-γ release in response to the immunodominant antigens ESAT-6, TB10.4, Ag85A, Rv2031 and DesA1 was assessed by ELISPOT on PBMC from 55 newly diagnosed pulmonary TB patients, 121 of their household contacts and 123 matched community controls, enrolled in a high-burden area. Results ESAT-6 and PPD ELISPOT responses were higher in the TB patient group compared to both contacts and controls (p Conclusion The present study therefore identifies DesA1 as an immunodominant antigen with the potential to contribute to improved immunodiagnosis.