Abstract: The invention relates to a manipulated professional antigen presenting cell (APC) having increased expression of a CD1 type II molecule, preferably at least a CD1d molecule, relative to a control non manipulated cell. The invention further relates to the use of PPARg modulators in the preparation of a pharmaceutical composition or kit for the treatment of a disease treatable by activation of CD1d restricted T-cells, e.g. in autoimmune diseases, allergies, post-transplant conditions or infectious diseases, or in the treatment of a neoplastic disease, e.g. skin cancer, hematological tumors, colorectal carcinoma, and therapeutic compositions and kits therefor. Furthermore, the invention relates to methods of manipulating professional APCs and kits therefor.