Abstract
Tuberculosis (TB) is ranked among the top 10 causes of death worldwide. New biomarker-based serodiagnostics and vaccines are unmet needs stalling disease control. Antigen 60 (A60) is a thermostable mycobacterial complex typically purified from Bacillus Calmette-Guérin (BCG) vaccine. A60 was historically evaluated for TB serodiagnostic and vaccine potential with variable findings. Despite containing immunogenic proteins, A60 has yet to be proteomically characterized. Here, commercial A60 was (1) trypsin-digested in-solution, analyzed by LC-MS/MS, searched against M. tuberculosis H37Rv and M.bovis BCG Uniprot databases; (2) analyzed using STRING to predict protein–protein interactions; and (3) probed with anti-TB monoclonal antibodies and patient immunoglobulin G (IgG) on Western blot to evaluate antigenicity. We detected 778 proteins in two A60 samples (440 proteins shared), including DnaK, LprG, LpqH, and GroEL1/2, reportedly present in mycobacterial extracellular vesicles (EV). Of these, 107 were also reported in EVs of M. tuberculosis, and 27 key proteins had significant protein–protein interaction, with clustering for chaperonins, ribosomal proteins, and proteins for ligand transport (LpqH and LprG). On Western blot, 7/8 TB and 1/8 non-TB sera samples had reactivity against 37–50 kDa proteins, while LpqH, GroEL2, and PstS1 were strongly detected. In conclusion, A60 comprises numerous proteins, including EV proteins, with predicted biological interactions, which may have implications on biomarker and vaccine development.
Highlights
IntroductionMycobacterium tuberculosis complex (MTB) are the causative agents of tuberculosis, and consist of several related pathogenic mycobacteria including M. africanum, M. caprae and M.bovis [2]
Tuberculosis (TB) persists as a top global cause of death, in low-income areas [1].Mycobacterium tuberculosis complex (MTB) are the causative agents of tuberculosis, and consist of several related pathogenic mycobacteria including M. africanum, M. caprae and M.bovis [2].The latter typically infects cattle and its attenuated strain, Bacillus Calmette-Guérin (BCG), has been used as a live TB vaccine since 1921 [3]
100 μg protein from two samples of commercially acquired Antigen 60 (A60) batch AT071002 (PBC Maes, Strasbourg, France) (A60 S1, A60 S2), which has been described as the peak exclusion fraction of lysate from log-phase grown BCG run through a Sepharose 6B size exclusion chromatography column (SEC) [34], were subjected to in-solution digestion using trypsin on separate days
Summary
Mycobacterium tuberculosis complex (MTB) are the causative agents of tuberculosis, and consist of several related pathogenic mycobacteria including M. africanum, M. caprae and M.bovis [2]. The latter typically infects cattle and its attenuated strain, Bacillus Calmette-Guérin (BCG), has been used as a live TB vaccine since 1921 [3]. The BCG affords poor protection for adults and is incompatible with immunocompromised individuals [4]. High priority research targets include discovery and development of antigen preparations for accurate biomarker-based non-sputum assays and improved vaccines that can be used to protect adults and immunocompromised/human-immunodeficiency virus (HIV)-infected individuals [8,10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
