(553e) Liposome Targeted Proliferation of Cytotoxic T Cells

Adoptive cell therapy (ACT) is an evolving personalized cancer immunotherapy. The approach has shown promising results in treating metastatic melanomas but has limited success in other malignancies due to: 1) lack of cytotoxic T cells found within tumor mileau, 2) the difficulty and cost associated with genetically modifying and expanding small populations of T cells ex vivo to therapeutic concentrations and 3) short term persistence of the inoculated T cells. To address these limitations, we hypothesized that liposomes can be used to deliver the T cell growth factor 'IL-2' directly to the cytotoxic T cells within the body, thereby circumventing the need for ex vivo expansion and significantly reducing the associated costs and complexities. Towards this goal, we have developed and characterized a novel approach to synthesize small unilamellar liposomes encapsulated with the desired molecules at high concentrations. We have also developed a unique thermal equilibration technique to co-load both hydrophobic and hydrophilic compounds within these liposomes at high concentrations. Utilizing this technique, liposomes containing IL-2 were created and functionalized with anti-CD8, and delivered to Tall-104 model cell line in vitro to demonstrate the efficacy of liposomal IL-2 in their proliferation and cytotoxicity against breast cancer cells.