CONTROLLED-RELEASE OF PEPTIDES AND PROTEINS FROM BIODEGRADABLE POLYESTER MICROSPHERES - AN APPROACH FOR TREATING INFECTIOUS-DISEASES AND MALIGNANCIES

An approach to enhance the immunogenicity of peptide-based vaccines fo r malaria and the immunoregulatory activity of recombinant human inter leukin-la (IL-1) is described. The approach involves the encapsulation of these molecules in, and their controlled release from, biodegradab le polyester microspheres of lactic and glycolic acids (PLGA). The mic rospheres are prepared by the modified solvent evaporation method base d on a double emulsion. Two types of microspheres composed of PLGA (75 :25 lactic/glycolic acid) and of different MW were constructed for eac h molecule. The release characteristics of these molecules from these microspheres were evaluated using spectroscopy and bioactivity assays. In vivo studies established the feasibility of PLGA carriers as an im munization vehicle for malaria peptide-based vaccines; the induced imm une responses in mice were stronger than those obtained with peptide i n complete Freund's adjuvant. In addition, these studies provide preli minary evidence that PLGA microspheres with encapsulated IL-1 can be u sed as a new strategy for the efficient delivery of this cytokine to t umor sites in immunotherapy.