Mycobacterium tuberculosis antigens Mtb32A and Mtb39A (Mtb32A and Mtb39A)

Mycobacterium tuberculosis antigens Mtb32A and Mtb39A are immunodominant proteins used as the primary components of the M72 (M72/AS01E) subunit vaccine candidate. Mtb32A (Rv0125) is a secreted serine protease of the S1C family that is highly conserved across various M. tuberculosis strains and is thought to contribute to bacterial virulence through proteolysis. Mtb39A (Rv1196) is a member of the PPE family of proteins (PPE18) that is membrane-associated and involved in immune evasion by inhibiting MHC class II antigen presentation in macrophages. In the context of the M72 vaccine, these two antigens are expressed as a recombinant fusion protein designed to elicit a robust Th1-mediated immune response, specifically activating CD4+ T cells to produce IFN-gamma and TNF-alpha. Clinical trials have demonstrated that targeting these antigens can provide approximately 50-54% protection against the progression of latent tuberculosis to active pulmonary disease in adults. The antigens are typically formulated with the AS01E adjuvant system to enhance their immunogenicity, and they remain a focal point of global efforts to develop a more effective replacement or supplement for the BCG vaccine.

Other names

M72 antigenMtb32AMtb39ARv0125Rv1196PepAPPE18Ra32Ra39Serine protease PepAPPE family protein PPE18

Induction of antigen-specific Th1-polarized CD4+ T-cell responses and humoral immunity to prevent progression of latent Mycobacterium tuberculosis infection to active pulmonary disease.