Underlying Mechanisms of Protection Involved in Immunocloak.

Background: We have previously reported on a novel organ-specific immunomodifying therapy that provides protection from early allograft rejection in the absence of systemic immunosuppressive drugs. This novel therapy is a nanobarrier membrane called ImmunoCloak, consisting of a matrix of laminin, proteoglycans, fibronectin, and collagens. The membrane "immunocloaks" the luminal surfaces within the renal vasculature by covering the point of contact between donor vascular endothelial cells and the recipient's immune cells, without adversely affecting renal function. The resulting nonthrombogenic and nonimmunogenic apical surface significantly delays the onset of rejection fivefold over untreated controls. Currently, our focus is to elucidate the mechanisms of protection provided by placement of the membrane.

Methods: The mechanisms underlying the protective effect of the ImmunoCloak treatment was evaluated using human peripheral blood mononuclear cells and by testing for antigen presentation by cytokine/chemokine analysis using the Luminex platform, T cell allogeneic responses were measured by flow cytometry, and diapedesis was assessed using transwell plates.

Results: We now report that ImmunoCloak interrupts antigen presentation thereby preventing early T cell activation and interferes with diapedesis. There was significant inhibition in the synthesis of proinflammatory cytokines with a concordant blockade of T cell-mediated responses. The placement of the ImmunoCloak also significantly reduced leukocyte migration through the endothelial cell layer by 93%.

Conclusions: Eliminating the need for nephrotoxic immunosuppressive drugs during the early posttransplant period could help to ameliorate the severity of delayed graft function and could provide a path to using more ischemically damaged renal allografts.