CD1 antigen presenting molecules are expressed in mature lympho-hematopoietic cells. Recently, we found that CD1c-restricted T cells recognized the methyl lysophosphatidic acid (mLPA) as self-lipid antigen and efficiently killed CD1c-expressing acute leukemia blasts. mLPA is an ether-lipid, which hallmarks peroxisome-derived biosynthesis, and was found accumulated in acute leukemia cells, whereas it was poorly present in normal hematopoietic cells. Nothing is known about the control of mLPA synthesis in malignant versus normal myeloid/lymphoid cells. This is critical to understand the pathophysiology of CD1 self-reactive T cell responses, as well as to improve leukemia recognition by CD1c-restricted T cells. We are currently trying to assess the role of different enzymes that may be implicated in mLPA biosynthesis, and are also found upregulated in most human tumors and involved in maintaining the malignant phenotype: 1. Alkylglycerone phosphate synthase (AGPS), the peroxisomal enzyme specifically responsible for ether-lipid synthesis; 2. Phospholipase A1/A2, which are involved in lysophospholipid generation; 3. Diacylglycerol kinase α (DGKα), a switch enzyme that can phosphorylate ether-lysoglycerolipids to generate ether-phospholipids. The expression of these enzymes was specifically knocked-down by lentivirus-mediated shRNA transfer, or their activity was inhibited by pharmacological treatments. Preliminary data were obtained with DGKα. Efficient and stable protein knock-down was obtained in Molt4 ALL cells, without affecting CD1c expression, which resulted in a significantly reduced recognition by mLPA-specific T cells. Interference of DGKα and the other enzymes is currently being investigated in Molt4 and THP1 acute leukemia cell lines.