Macrophage-activating lipopeptide 2 (MALP-2) is a lipopeptide Toll-like receptor (TLR)-2 and 6 agonist. It is used in immunological research to simulate Mycoplasma bacterial infections and activate immune cells. MALP-2 holds promise as a novel vaccine adjuvant due to its activation of TLRs. It also promotes vascular, bone, and wound healing.
MALP-2 has the structure S-2,3-bis(palmityloxy)-(2R)-propyl-cysteinyl-GNNDESNISFKEK and is a post-translationally modified CGNNDESNISFKEK peptide in which in the N-terminus cysteine residue sidechain is linked to a diacylglycerol moiety where the two acyl groups are both derived from palmitic acid.
MALP-2 was initially named mycoplasma-derived high-molecular-weight material (MDHM) and, as the name suggests, had originally been isolated from Mycoplasma fermentans as an amphiphilic molecule with macropage-activating properties. This discovery helped explain how Mycoplasma bacteria can provoke immune responses despite lacking a cell wall.