Plays a key role in regulating innate and adaptive immune responses through human Toll-like receptor 2 (TLR2). Interacts with TLR2, leading to the subsequent activation of the mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-kappa-B) signaling pathways. Induces macrophage activation by augmenting the expression of several cell surface molecules (CD40, CD80, CD86 and MHC class II) and pro-inflammatory cytokines (TNF-alpha, IL-6 and IL-12p40) within macrophages. Also participates in adaptive immunity by directing Th1-polarised immune responses (PubMed:25586105). Stimulates specific humoral and cellular immune responses in tuberculosis (TB) patients (PubMed:17328725, PubMed:19467342, PubMed:23136116). Induces a strong IgG(1) antibody response and an increased Th1/Th2 type immune response in mice (PubMed:18426397). Interacts with human TLR2. Expressed during infection. Expressed during exponential growth in vitro. Immunodominant antigen that could be used for serological diagnosis to distinguish patients with active tuberculosis from M.bovis BCG-vaccinated individuals (PubMed:17328725, PubMed:19467342, PubMed:23136116). Candidate for development of a vaccine for the control of tuberculosis (PubMed:18426397, PubMed:25586105). Belongs to the mycobacterial PPE family.