Proteomic characterization of a second-generation version of the BCGΔBCG1419c vaccine candidate by means of electrospray-ionization quadrupole time-of-flight mass spectrometry

Abstract

Tuberculosis (TB) is the most important infectious disease worldwide, based on the number of new cases and deaths reported by the World Health Organization. Several vaccine candidates against TB have been characterized at the preclinical and clinical levels. The BCGΔBCG1419c vaccine candidate, which lacks the BCG1419c gene that encodes for a c-di-GMP phosphodiesterase, provides improved efficacy against chronic TB, reactivation from latent-like infection, and against TB in the presence of type 2 diabetes in murine models. We previously reported that compared to wild type BCG, BCGΔBCG1419c changed several proteins. Here, using a label-free proteomic approach, we confirmed that a novel, second-generation version of BCGΔBCG1419c maintains changes in antigenic proteins already reported, including differences in secreted proteins, and also found that it modifies its production of proteins involved in redox and nitrogen/protein metabolism, compared with wild type BCG. This work contributes to the proteomic characterization of a novel vaccine candidate that is effective against chronic TB.

Vaccination with BCGΔBCG1419c protects against pulmonary and extrapulmonary TB and is safer than BCG

“…Based on these findings, we developed a second-generation version of BCGΔBCG1419c, devoid of antibiotic markers. Changes in the production of cellular and secreted proteins by this novel BCGΔBCG1419c compared with parental BCG were recently reported 11 , and found to match changes in antigenic proteins reported for the Hyg R first-generation mutant 12 . Using the antibiotic-less version of BCGΔBCG1419c, here we compared its in vitro growth, its replication in murine macrophages, its safety in immunocompetent hosts (BALB/c and C57BL/6 mice, and Hartley guinea pigs) and immunocompromised hosts (athymic nu/nu mice), to that of parental BCG Pasteur.…”

“…In this work, we observed a similar in vitro growth profile to its parental BCG. In addition, we recently reported that this novel version of BCGΔBCG1419c maintain changes in antigenic proteins compared with BCG 11 , therefore fostering our interest in its preclinical characterization. Among these changes in antigenic proteins, compared with wild type BCG, the BCGΔBCG1419c vaccine candidate increased secretion of GroEL1, DnaK and GroES 11 , which might contribute to an increased recognition by immune cells prompting a more efficient clearance of BCGΔBCG1419c in vivo (Fig.…”

“…Mycobacterium bovis BCG Pasteur ATCC 35734 (hereafter referred to as BCG), or its isogenic derivative, second generation M. bovis BCGΔBCG1419c 11 were cultured in Middlebrook 7H9 broth supplemented with 0.2% glycerol, 10% OADC, and 0.05% Tween 80, at 37 °C, 5% CO 2 , 100 rpm, up to an OD600nm ≈ 0.8, and used for safety studies in mice and guinea pigs, evaluation of antibody response in guinea pigs, RNA isolation as described 10 and real time qPCR assays to determine relative expression of the sigA and BCG1419c genes to that of rrs as recently reported 33 . For evaluation of efficacy in guinea pigs, BCG and BCGΔBCG1419c were cultured in Proskauer and Beck (P&B) medium with 0.1% Tween 80 to mid-log phase.…”

Evaluation of early innate and adaptive immune responses to the TB vaccine Mycobacterium bovis BCG and vaccine candidate BCGΔBCG1419c

“…These STING agonists have shown potential use as novel vaccine adjuvants, as evidenced by their immunostimulatory properties, due to their ability to increase antigen-specific T cell and humoral responses 52 , 53 . Because of the deletion of the c-di-GMP phosphodiesterase-encoding gene BCG1419c 54 , 55 we expect the BCGΔBCG1419c vaccine candidate to produce more c-di-GMP, therefore modulating the type I IFN response to possibly increase its efficacy against TB. Further to this, BCGΔBCG1419c has a modified proteomic repertoire compared with parental BCG, including changes in cellular and secreted antigenic proteins 54 which could also lead to a differential immune response which ultimately impact, in a positive manner, protection against pulmonary TB.…”

BCGΔBCG1419c increased memory CD8+ T cell-associated immunogenicity and mitigated pulmonary inflammation compared with BCG in a model of chronic tuberculosis

“…Based on these results, we developed a second-generation version of BCGΔBCG1419c, which is devoid of Hyg r , now in BCG Pasteur ATCC 35734. The antibiotic-less BCGΔBCG1419c maintains the differential production of cellular antigenic proteins first described for this vaccine candidate 21 , while it also increases the secretion of Tuf, GroEL1, DnaK and GroES compared with that of parental BCG 22 . Moreover, the new BCGΔBCG1419c was safer than parental BCG, as evidenced by the attenuated features both in vitro and in vivo 23 .…”