Year: 2006
Type: dissertation
Abstract: The effectiveness of most chemotherapeutic regimens is limited by the toxicity of\nthe therapy to normal healthy cells. Therapies to selectively modulate abnormal T cells\nbearing the interleukin 2 receptor (IL-2R) have been developed to treat diseases\nassociated with aberrant immune response. This study describes the development and\noptimization of a targeted gene or oligonucleotide therapy vehicle to IL-2R bearing T\ncells for selective elimination of these cells. In this work, a monoclonal antibody to the\nIL-2R was used to target the oligonucleotide delivery vehicle which consisted of a\npolyamidoamine dendrimer. Optimization of the delivery vehicle involves\nunderstanding the factors that govern its association with oligonucleotide, the pathway\nof IL-2R endocytic trafficking, and the stability of the oligonucleotide in the biological\nmilieu. Oligonucleotide stability in a cellular environment was examined intra- and\nextracellularly. Results showed that the rate of intracellular degradation of\noligonucleotides was much greater than extracellular degradation. Binding of\noligonucleotides to dendrimers was demonstrated as a function of dendrimer generation.\nThe total binding capacities for dendrimers differed depending upon dendrimer size and\nsurface group, whereas equilibrium binding affinity was comparable for all dendrimers\ntested. Binding of oligonucleotide delivery vehicle to the cell surface and subsequent\ninternalization was inversely related to dendrimer size, and in all cases, significantly less\nthan binding and internalization of the natural ligand for the IL-2R. Based on\nexperimental results, a kinetic model of the delivery vehicle was derived which includedthe dependence of binding and internalization on dendrimer size and surface charge and\nintracellular degradation of oligonucleotide. Based on model predictions, we show that\nlarger dendrimers carry more oligonucleotide than the smaller dendrimer vehicles, and\ndelivery is more effective with larger vehicles. This work establishes our ability to\npredict the effects of different delivery vehicle properties on oligonucleotide delivery\nand aids in the development of design criteria for new vehicles for delivery of antisense,\nsiRNA, or genes to IL-2R bearing cells.
Author: Wanida Wattanakaroon
Language: English
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2745702663