Antisense oligodeoxynucleotides prevent acute cardiac allograft rejection via a novel, nontoxic, highly efficient transfection method

Background We hypothesized that ex vivo donor allograft transfection with a ntisense oligodeoxynucleotide (AS ODN) would inhibit the expression of inte rcellular adhesion molecule (ICAM)-1, an important mediator of T-cell adhes ion and costimulation, and therefore suppress acute cardiac rejection, Methods, Hearts were transfected ex vivo with AS, reverse AS ODN, or saline by applying 3 atm pressure for 45 min at 4 degrees C, Grafts were then tra nsplanted into allogenic recipients +/- treatment with leukocyte function-a ssociated antigen (LFA)-1 monoclonal antibody (mAb) (1.5 mg/kg intravenousl y), cyclosporine (2.5 mg/kg/day p,o,), or rapamycin (0.025 mg/kg/day intrap eritoneally), Reperfusion injury was assessed in grafts harvested at early time points using the myeloperoxidase, %wet weight, and %contraction band n ecrosis assays; transfection efficiency was assessed using fluorescent micr oscopy; and efficacy of ICAM-1 blockade was assessed using immunohistochemi stry. Other grafts were followed until rejection with donor/third-party ski n grafting, adoptive transfer, and interleukin 2 infusion studies in select ed recipients. Results. Transfection was highly efficient (fluorescein isothiocyanate-ODN in 48+/-5% of total myocardial nuclei), nontoxic, and reduced the ICAM-1-po sitive area to 53+/-14% versus having no effect on MHC class I expression ( n=4), The incidence of survival >60 days after AS ODN + LFA-1 monoclonal an tibody was 75%, significantly higher than other regimens, Conclusion. AS ODN hyperbaric transfection proved highly efficient, effecti ve at ICAM-1 blockade, and induced cardiac allograft tolerance when combine d with LFA-1 monoclonal antibody. This highly targeted alteration of allogr aft immunogenicity may have an important role in future immunosuppressive s trategies.