The current invention teaches the systemic treatment with a standard commercial polyethylenimine (PEl) preparation mixed with bacterial plasmid DNA (PEI/pDNA complexes or 'nanoparticles') induced endogenous expression of the enzyme indoleamine 2,3 dioxygenase (IDO) in lungs and lymph nodes (LNs) of treated mice. IDO induction in these tissues was detected by RT-PCR to detect IDO RNA, and HPLC analysis to detect the amino acid tryptophan (Trp, an IDO substrate) and kynurenine (Kyn, a tryptophan catabolite produced by cells expressing IDO). We have previously shown (and patented) that IDO is a potent inhibitor of innate and adaptive immune responses. However potent, effective and nontoxic inducers of IDO are not known, and would be of great benefit for research and clinical applications. Therefore, these novel findings support the hypothesis that PEl/DNA treatment is an effective method to; (a) suppress undesirable immunity that targets healthy tissues in autoimmune and allergic disease syndromes, and following transplantation of organs, tissues and cells and (b) promote immunologic tolerance to auto (self) and alto (donor) antigens that reduces the need for global immunosuppression in these clinical settings.
Case ID: GRU #2011-012