TLR1 and tuberculosis: Nevertheless, studies have demonstrated PPE50 immunological properties: PPE50-132 binds TLR1 on THP-1 macrophages, upregulating anti-inflammatory IL-10 responses23; PPE50-381 peptides are presented via MHCII in BCG-infected macrophages17; and PPE50/PPE51 peptides induce significant IFNγ production in PBMCs from LTBI individuals and TB patients17,18, with higher responses in LTBI.