CHARACTERIZATION OF A SUSTAINED-RELEASE DELIVERY SYSTEM FOR COMBINED CYTOKINE PEPTIDE VACCINATION USING A POLY-N-ACETYL GLUCOSAMINE-BASED POLYMER MATRIX/

Identification of tumor-associated antigens (TAAs) and their class I M HC-restricted epitopes now allows for the rational design of peptide-b ased cancer vaccines, A biocompatible system capable of sustained rele ase of biologically relevant levels of cytokine and TAA peptide could provide a more effective microenvironment for antigen presentation, Ou r goal was to test a sustained-release cytokine/TAA peptide-based form ulation using a highly purified polysaccharide [poly-N-acetyl glucosam ine (p-GlcNAc)] polymer, Granulocyte-macrophage colony-stimulating fac tor (GM-CSF; 100 mu g) and MART-1((27-35)) peptide (128 mu g in DMSO) were formulated into p-GlcNAc. Peptide release was assayed in vitro us ing interleukin 2 production from previously characterized MART-1((27- 35))-specific Jurkat T cells (JRT22), GM-CSF release was assayed via E LISA and proliferation of M-07e (GM-CSF-dependent) cells, Local bioava ilability of MART-1((27-35)) peptide for uptake and presentation by an tigen-presenting cells was demonstrated for up to 6 days (>0.5 mu g/ml ). More than 1.0 mu g/ml GM-CSF was concomitantly released over the sa me period, Biocompatibility and local tissue response to p-GlcNAc rele asing murine GM-CSF was determined in C57BL/6 mice via s.c. injection using murine GM-CSF (0.2 mu g/ml) in 200 mu l of a 2.5% polymer gel, S ignificant lymphocytic and eosinophilic infiltration was observed 27 d ays after injection with polymer containing murine GM-CSF, The results of our studies show that this biocompatible system is capable of a su stained concomitant release of biologically active peptide and cytokin e into the local microenvironment. These findings support further stud ies to validate a p-GlcNAc delivery system vehicle for a cytokine/TAA peptide-based cancer vaccine.