TABLE 2

Descriptions of the Mycobacterium tuberculosis (MTB) antigens included in this review

Antigens	Synonyms	Descriptions and biological activities	References
esxA	Rv3875, ESAT-6	6 kDa early secretory antigenic target of unknown function. Elicits high level of INF-γ from memory effector cells during the first phase of a protective immune response. Component of QuantiFERON test, and absent in BCG strain.	[17, 77]
esxB	Rv3874, CFP10	10 kDa culture filtrate antigen of unknown function.	[77]
esxW	Rv3620	Putative ESAT-6 like protein 10 of unknown function.	[77]
esxV	Rv3619	Putative ESAT-6 like protein 1 of unknown function.	[77]
Rv1813c	Rv1813c	A conserved hypothetical protein of unknown function.	[78]
LAM		Components of MTB-cell wall. Inhibit IFN-γ mediated macrophage activation; T-cell proliferation, IL-12 production, neutrophil recruitment, DC activation.	[79]
fbpA	Rv3804c, Ag85a	Fibronectin binding protein A and components of Ag85 complex (Ag85a), possesses a mycolyltransferase activity (85A) required for the biogenesis of trehalose dimycolate (cord factor), main component for maintaining cell wall integrity.	[77]
fbpB	Rv1886c, Ag85b	Fibronectin binding protein B and components of Ag85 complex (Ag85b). Secreted antigen acts as mycolyltransferase (85B), which is involved in cell wall mycoloylation.	[77, 80]
fbpC	Rv0129c, Ag85c	Fibronectin binding protein C and components of Ag85 complex (Ag85c). Secreted antigen acts as mycolyltransferase (85C), which is involved in cell wall mycoloylation.	[77]
espB	Rv3881c	Secreted ESX-1 substrate protein B, EspB. A conserved alanine and glycine-rich protein of unknown function.	[77]
mpt70	Rv2875	Major secreted immunogenic protein of unknown function.	[77]
Acg	Rv2032	Acg (acr-coregulated gene). Conserved protein of unknown function.	[77]
Rv0831	Rv0831	A conserved protein of unknown function.	[77]
bfrB	Rv3841	Bacterioferritin. Intracellular molecule involved in iron storage.	[77]
Rv0831c	Rv0831c	A conserved protein of unknown role.	[77]
HspX	Rv2031c, 16/14 kDa	Heat shock protein (alpha-crystallin homolog). Stress protein induced by anoxia. Proposed role in long-term survival of the bacilli during latent infections.	[77, 79]
PstS1	Rv0934, 38kDa	Periplasmic phosphate-binding lipoprotein (PBP-1). Immunodominant antigen involved in active transport of inorganic phosphate across the membrane.	[34, 77]
Ssb	Rv0054	Helix-destabilising protein involved in DNA replication, recombination and repair.	[77]
lipC	Rv0220	Probable esterase LipC with unknown function. A lipolytic enzyme probably active in cellular metabolism.	[77]
Rv2958c	Rv2958c	Possible glycosyl transferase with unknown function. Probably involved in cellular metabolism and has a role in resistance to killing by human macrophages.	[77]
Rv2994	Rv2994	Probable conserved integral membrane protein with unknown function; could be involved in efflux system.	[77]
Rv1813c	Rv1813c	A conserved hypothetical protein of unknown function.	[81, 82]
A60		Located in the cytosol, macromolecular antigen complex, conserved in typical and atypical mycobacteria, main component of commercial ELISA kit (Anda Biologicals, Strasbourg, France).	[26]
HbhA	Rv0475	Protein regulated by iron that promotes extrapulmonary dissemination and facilitates adherence to epithelial cells. Induces mycobacterial aggregation.	[79]
Tpx	Rv1932	Probable thiol peroxidase with antioxidant activity. Could remove peroxides or H₂O₂.	[77]
Apa	Rv1860, MPT-32 45/47kDa	Alanine- and proline-rich secreted protein (fibronectin attachment protein). Could mediate bacterial attachment to host cells.	[77]
AcrA1	Rv3391	Multifunctional enzyme with acyl-CoA-reductase activity. Possibly involved in cellular metabolism.	[77]
hrp1	Rv2626c	Hypoxic response protein 1 of unknown function.	[77]
PPE17	Rv1168c	PPE of unknown function. Induces strong B-cell responses.	[4, 77]
PPE42	Rv2608	PPE family protein of unknown function.	[77]
PPE55	Rv3347c	PPE family protein of unknown function.	[77]
MDP1		A histone-like nucleoid associated protein expressed by many mycobacterial species. Could play a role in long-term survival of mycobacteria.	[17]

INF: interferon; BCG: bacille Calmette–Guérin; LAM: lipoarabinomannan; IL: interleukin; DC: dendritic cell; MDP1: mycobacterial DNA-binding protein 1; HbhA: heparin binding haemagglutinin (adhesin); Ssb: single-strand binding protein; H₂O₂: hydrogen peroxide; PPE: proline-proline-glutamic acid.