Moreover, 25-OCH<sub>3</sub>-PPD significantly inhibited glucose-regulated protein 78 (GRP78; the major ER stress marker) expression in TM-induced ER stress in HepG2 and HEK293T cells, suggesting that 25-OCH<sub>3</sub>-PPD could attenuate ER stress in these cells.
Cell-mediated immunity was characterized in whole blood samples as the differential release of interferon-gamma in response to bovine purified protein derivative (PPDb) and avian PPD (PPDa) as well as the release of this cytokine in response to the <i>M. bovis</i> proteins 6 kDa early secretory antigenic target (ESAT-6)/10 kDa culture filtrate protein (CFP-10).
The tuberculin skin test (TST), the Quantiferon (QFT) and a prolonged lymphocyte stimulation test using either ESAT-6/CFP-10 (LST-EC) or PPD (LST-PPD) were evaluated in a cohort of 495 individuals, suspected to have LTBI, in a low endemic country.