Mycobacterium tuberculosis antigens Ag85B and ESAT-6 (Ag85B/ESAT-6)

Mycobacterium tuberculosis antigens Ag85B and ESAT-6 are two of the most immunodominant proteins secreted by the causative agent of tuberculosis. Ag85B (fbpB) is a mycolyltransferase essential for the synthesis of trehalose dimycolate, a major component of the mycobacterial cell wall (UniProt P9WQP3). ESAT-6 (EsxA) is a potent virulence factor that plays a critical role in disrupting the phagosomal membrane, allowing the bacteria to escape into the host cell cytosol (UniProt P9WNK5). Because these proteins are expressed early during infection and are highly recognized by the human immune system, they are frequently combined into fusion proteins for subunit vaccine development. These vaccine candidates, such as H1 or H56, aim to elicit a robust Th1-type cellular immune response to provide protective immunity or boost the efficacy of the existing BCG vaccine (PubMed: 11169414, 21402744). Clinical applications focus on both prophylactic and therapeutic strategies to control Mycobacterium tuberculosis infection.

Other names

Antigen 85BEarly secretory antigenic target 6 kDafbpBEsxAMycolyltransferase Ag85BH1 fusion protein6 kDa early secretory antigenic target

Induction of antigen-specific Th1-mediated immune response, characterized by the production of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) by CD4+ T-cells to enhance mycobacterial clearance.