| Gene therapy based on small interfering RNA (siRNA) and plasmid DNA (pDNA) is potential therapeutic agents, which can target specific genes causing disease, disease promoting, cancer or inflammation by sequence specific gene mechanism. However, there are not proper gene carriers that can deliver those therapeutic gene agents into the infected cells or cancer cells. The key required features to be a gene carrier is protecting them from degradation by nuclease before they can do their activities and delivering them to the target cells. In our study, we tried to target T-lymphocyte, CD8T cells. To target lymphocytic cells, the carrier should have further properties. For example, the carrier itself should not induce any immunogenicity. They should be able to be modified to meet the specificity requirement in order to interact with the specific T cells. There are many drug carriers have been developed, such as polymer-based carrier, lipid-based carrier, albumin-based carrier and protein-based carrier. However, we were focused on Poly (lactic-co-glycolic acid) polymer-based carrier and nanoscale (<1 mum). Because it has been used in a host of Food and Drug Administration (FDA) approved therapeutic devices and they could be easily incorporated with cationic polymers, such as polyethylenimine (PEI), polyarginine, and protamine. Their surface, Carboxylates could be cross-linked with primary amines of anti-CD8 antibodies by EDC/NHS chemical conjugation. Non-specific targeting to 293Tcells and specific targeting to CD8T cells have been studied. Cellular binding and uptake were determined by flow cytometry, fluorescence microscope, and confocal microscope. The PEI modified PLGA nanoparticles shown about 50% of GFP down regulation by carried si-GFP-RNA and sustained YFP expression by PLGA nanoparticles delivering pEYFP plasmid for 1 week. FITC tagged siRNA loading PLGA nanoparticles were conjugated to anti-CD8AB and gave the highest GFP expression in 1200Tcell (CD8) compare to 1010Tcell (CD4) for 24 hr and 48 hr incubation. The similar results have shown in the lymphocytes, 1010Tcells and 1200Tcells transfected by antiCD8-AB-PLGA nanoparticles carrying Alexa 648 flur. Hence we can conclude that PLGA nanoparticles can carry siRNA and plasmid DNA and can be chemically conjugated with antibodies which against specific cellular antigens and are promising candidate polymers for selective drug delivery systems to target specific cells in systemic delivery. |
