Background & aims: Systemic treatment of Crohn's disease patients using recombinant interleukin (rIL)-10 has not resulted in significant therapeutic benefit presumably because of limited bioavailability and unexpected proinflammatory effects of high-dose rIL-10. Ex vivo gene transfer of the interleukin (IL)-10 gene to gut-homing CD4(+) cells may lead to improved long-term management.
Methods: Peripheral blood mononuclear cells (PBMCs) were transduced with a retroviral vector containing the IL-10 and green fluorescent protein (GFP) gene or a control vector containing GFP only. Transduced CD4(+) cells were sorted and maintained in culture for phenotypic and functional analysis.
Results: Stimulated IL-10-GFP CD4(+) cells produced significantly higher levels of IL-10 than control cells for at least 4 months. The IL-10 transgene was biologically active and decreased proliferation of IL-10-GFP CD4(+) cells as well as expression of major histocompatibility class (MHC) class II, proliferation of autologous responder cells, and IL-12 production by dendritic cells (DCs). The majority of transduced CD4(+) cells had a gut-homing potential because they expressed the mucosal integrin alpha4beta7, and displayed efficient binding to MAdCAM-1-expressing cells in vitro.
Conclusions: Transduction of peripheral blood CD4(+) lymphocytes with IL-10 results in a regulatory phenotype. The use of regulatory gut-homing human CD4(+) cells may provide a novel approach to local delivery of immunomodulatory signals to the intestine in Crohn's disease.