CTSD and infection: Of the seventeen proteins unique to the PMG, seven increased their expression levels after feeding (D-3-phosphoglycerate dehydrogenase; putative sulfotransferase; putative multicopper oxidase; multicopper oxidase; salivary platelet aggregation inhibitor 1; putative cathepsin l-like cysteine protease, and peptidase A1 domain-containing protein) [7], while cathepsin D did so after infection with T. cruzi [48].