The Mycobacterium tuberculosis PPE protein Rv1168c induces stronger B cell response than Rv0256c in active TB patients

The N-terminal domain of Mycobacterium tuberculosis PPE17 (Rv1168c) protein plays a dominant role in inducing antibody responses in active TB patients

“…tuberculosis is 346 amino acids in length and is characterized by the presence of a conserved N-terminal domain of approximately 180 amino acids (S1 Fig). The expression and purification of recombinant full-length PPE17 protein (PPE17) was carried out following the methods as described by us earlier [15,22]. For purification of N-terminal domain of PPE17 (N-PPE17) protein, ORFs corresponding to 1 to 173 amino acids was amplified from BAC library contig Rv71 (C2) [kindly provided by Dr. Shekhar C. Mande, CDFD, Hyderabad] using forward The amplified products were cloned in frame with N-terminal poly-histidine tag in pRSET-A vector (Invitrogen, Carlsbad, CA, USA).…”

“…coli BL21 (DE3) pLysS cells. All these proteins were purified under native condition as described by us earlier [15, 22, 30]. Briefly, primary cultures were grown in Terrific broth (Becton Dickinson, Difco, Sparks, MD) containing ampicillin (100 μg/ml) at 37°C overnight.…”

“…Interestingly, PPE17 is reported to be surface exposed and immunogenic [28] and genes that are homologous to PPE17 are found to be absent in the non-tuberculous mycobacterial species. We reported earlier that PPE17 could discriminate patients with active TB from BCG-vaccinated healthy individuals [15,22]. Interestingly, we observed that PPE17 displayed higher sensitivity in detecting extrapulmonary and smear negative pulmonary TB cases than early secreted antigenic target 6 protein (ESAT-6) and purified protein derivative (PPD) as well as other PPE proteins [14–18,21,22].…”

“…tuberculosis proteins that can provide enough sensitivity and specificity to be used as a first-line screening tool for serodiagnosis of TB. Various studies indicate that PPE proteins induce B-cell responses in active TB patients and can be used for serodiagnosis of TB [12–22]. One of the PPE proteins, PPE17 (Rv1168c) is shown to be up-regulated in conditions that mimic the macrophage environment features [23–26].…”

“…We reported earlier that PPE17 could discriminate patients with active TB from BCG-vaccinated healthy individuals [15,22]. Interestingly, we observed that PPE17 displayed higher sensitivity in detecting extrapulmonary and smear negative pulmonary TB cases than early secreted antigenic target 6 protein (ESAT-6) and purified protein derivative (PPD) as well as other PPE proteins [14–18,21,22]. We also demonstrated that PPE17 is a potent T-cell antigen which elicited stronger gamma interferon response as compared to PPD [15].…”