Interleukin-10 plasmid construction and delivery for the prevention of type 1 diabetes

Studies of animals with spontaneous autoimmune diabetes have revealed that autoreactive T cells that mediate islet beta cell destruction can be manipulated by the administration of Th-2 cytokines. In this article, the effect of interleukin-10 (IL-10) gene delivery was evaluated in vitro and in vivo with a novel IL-10 plasmid, pSI-IL-10-NF kappa B. In PSI-IL-10-NF kappa B, the expression of the IL-10 gene was driven by the SV40 promotor/enhancer. The nuclear factor kappa B (NF kappa B) binding sites were also introduced to facilitate nuclear transport of the plasmid in the cell. In vitro transfection assay with pST-IL-10-NF kappa B showed a similar expression level of IL-10 to the plasmid without NF kappa B binding sites (pSI-IL-1 0). pSI-IL-10-NF kappa B and pSI-IL-10 were intravenously injected into 5-week-old nonobese diabetic (NOD) mice using polyethylenimine (PEI) as a gene carrier. Both groups had persistent gene expression, longer than 5 weeks, and secreted the similarly high IL-10 serum levels. Interestingly, the degree of insulitis in the pSI-IL-10-NF kappa B group was improved over the pSI-IL-10 group, PEI-only group, and noninjected controls. The serum glucose levels showed that single injection of pSI-IL-10-NF kappa B prevented the development of diabetes in 100% of the pSI-IL-10-NF kappa B-injected animals (5/5), while that of pSI-IL-10 prevented diabetes in 40% of the treated animals (2/5). These results suggest that pSI-IL-10-NF kappa B with PEI can effectively reduce the incidence of insulitis and type 1 diabetes in NOD mice.