Abstract
Biodegradable microparticles (MPs) were prepared to contain dinitrophenylated bovine serum albumin (DNP-BSA) and the cytokines interleukin (IL)-5 and IL-6. The conformational integrity of these MPs was examined by scanning electron microscopy. DNP-BSA was evaluated, postentrapment, by a bicinchoninic acid assay, SDS-PAGE, isoelectric focusing, Western blotting, ELISA and spectrophotometric analysis. The bioactivity of the ILs postentrapment was measured using bioassays. Ocular-topical (OT) and intraperitoneal (IP) administration of loaded MPs induced serum IgG, tear IgA and vaginal wash (VW) IgA responses which persisted up to 45 days post secondary immunization (P2°). OT and IP delivery elicited serum IgG and tear IgA responses up to 140 days post tertiary immunization (P3°). VW IgA responses persisted up to 45 days and 140 days P3° following OT and IP delivery, respectively. Overall, the inclusion of cytokines in antigen containing MPs enhanced tear IgA antibody levels following OT delivery P2°, while elevated VW IgA responses occurred following IP delivery P2° and P3°. These data demonstrate that antigen/cytokine loaded MPs can potentiate long-term mucosal antibody responses at both target and distal effector sites as well as elicit circulating antibodies.