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Single-Dose Vaccine Carrier for Modulation of Immune Response Mechanisms

Single-Dose Vaccine Carrier for Modulation of Immune Response Mechanisms. Matt J. Kipper 1 , Jennifer Wilson 2 , Michael Wannemuehler 2 , and Balaji Narasimhan 1 1 Department of Chemical Engineering, Iowa State University

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Single-Dose Vaccine Carrier for Modulation of Immune Response Mechanisms

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  1. Single-Dose Vaccine Carrier for Modulation of Immune Response Mechanisms Matt J. Kipper1, Jennifer Wilson2, Michael Wannemuehler2, and Balaji Narasimhan1 1Department of Chemical Engineering, Iowa State University 2Department of Veterinary Microbiology and Preventive Medicine, Iowa State University 68a – AIChE Annual Meeting, November 9, 2004

  2. Controlled Release • Single dose • Tailored release kinetics • Targeted to specific organs tissues or cells Controlled Release Improves on Conventional Administration Schedules Toxicity Therapeutic Range Concentration No Activity Time • Conventional • Poor patient compliance • Poor concentration control • Overdose potential

  3. Many Controlled Release Formulations have been Marketed

  4. Hydrolytically labile Polyanhydrides are Excellent Candidates for Controlled Release Hydrophobic  Surface erosion Poly[1,6-bis (p-carboxyphenoxy)hexane] Poly(CPH) Biocompatible degradation products  -COOH Mutually incompatible Poly(Sebacic anhydride) Poly(SA) Narasimhan and Kipper, Adv. Chem. Eng. (2004)

  5. Bulk Erosion Combined Polymer Chemistry and Microstructure Affects Erosion and Release Kinetics Surface Erosion Cumulative Mass Released Time Tailored release kinetics Shen, Kipper, Dziadul, Lim, Narasimhan, J. Controlled Release (2002)

  6. Current Vaccine Administration Schedules are Non-Ideal • >700,000 neonatal deaths world-wide from tetanus • Conventional injection schedules • Many injections • Patient compliance • Controlled release technology • Single injection • Multiple formulations • NIH Lists Single Dose Vaccines as #1 Grand Challenge in Global Health http://www.grandchallengesgh.org/

  7. Controlled Release Formulations Offer Several Advantages for Vaccines • Polyester-based (PLGA) single-dose vaccines • Protective immunity possible w/single-dose (Corradin, O’Hagan) • Antibody titer and isotype/subclass similar to that in alum-based systems (Corradin) • Acidic/aqueous microenvironment reduces antigenicity (Schwendeman, Langer) • Polyanhydrides • Hydrophobic microenvironment • Protein stabilization • Modulated release kinetics • Reduced acidity • No studies with vaccine formulations

  8. Two Immune Response Mechanisms Offer Different Protection TCR Circulation B Cell Th1 Th1 Secreted Antibody Humoral (Th1) response MHC II Pathogen Migration to draining lymph node TCR Circulation Th2 Th2 DC Cytotoxic T Cell MHC I MHC I Cellular (Th2) response Infected Cell

  9. Research Paradigm Polymer/APC Interactions Hydrophobic Hydrolyzable Surface Erosion Cytokine Profile Antigen Stabilization Immune Activation Controlled Release Novel Adjuvants for Single-Dose Vaccines

  10. Goal Engineer tetanus toxoid (TT)-loaded polyanhydride microspheres and study in vivo immune response

  11. Emulsify, add 4ml of silicon oil (dropwise) saturated with MeCl2 Add to 300ml of n-heptane, stir three hours to allow MeCl2 to evaporate Continue emulsifying, to form outer emulsion Filter, rinse, dry Microspheres Fabricated by W/O/O Double Emulsion 100mg polymer in 4ml MeCl2 5mg protein in 100ml water

  12. Non-Porous Microspheres Provide Extended Release Kinetics 20:80 • Microspheres incubated in 0.1M phosphate buffer (pH 7.4) • TT antigen concentration determined by BCA assay 50:50

  13. Polyanhydride Microspheres Induce Dose-Dependent Inhibition • 3 C3He/OuJ mice per group • IM injection (right quadriceps) • Unencapsulated TT and blank 20:80 CPH:SA microspheres • 50% cottonseed oil/saline emulsion • ELISA for TT-specific IgG at 1:400 dilution

  14. TT-Loaded Microspheres Provide Immunity • 5 C3He/OuJ mice per group • Injected IM (right quadriceps) with 2% loaded TT-loaded microspheres (0.5mg) and/or bolus of unencapsulated TT (0.5mg) • Bled weekly from saphenous vein • TT-specific IgG antibody titer determined by ELISA

  15. TT-Loaded Microspheres Provide Immunity 20:80 CPH:SA 50:50 CPH:SA + Bolus only Blank microspheres Blank plus bolus TT microspheres TT microspheres plus bolus xEquivalent dose of TT

  16. 20:80TT Microspheres Provide High-Avidity Antibody • 10–week serum samples tested by ELISA • Sodium thiocyanate dissociates antibody from TT • Avidity index is maximum molarity of NaSCN that results in <50% dissociation in 20-minute incubation

  17. VIII – 20:80 blank w/bolus IX – 20:80TT X – 20:80TT w/bolus XII – 50:50 blank w/bolus XIII – 50:50TT XIV – 50:50TT w/bolus XV – Equivalent TT dose 20:80 CPH:SA Microspheres Provide High-Avidity Antibody 20:80 CPH:SA provides high titer and high avidity  protective immunity

  18. Immune Response Pathway can be Tuned by Microsphere Formulation • IgG1 and IGg2a isotypes determined by ELISA • Ratio of OD at 1:400 dilution • IgG2a = Th1 • IgG1 = Th2 20:80 50:50

  19. Migration to lymph node not delayed Inflammatory cytokine context results in balanced response DCs IL-12 Unencapsulated immunogen Migration to lymph node not delayed DC Antigen-driven (TH2) response How do 20:80 Microspheres Mediate Immune Response? Inflammatory cues wane Antigen-driven (TH2) response Migration to lymph node delayed by hydrophobic adjuvant Microspheres degrade, releasing antigen DC Immunogen-loaded microspheres

  20. Summary • Low polymer doses provide adjuvant effect • TT-Loaded microspheres provide immunity • Preserved antigenicity • Sustained exposure to antigen provides secondary immune response • Antibody titers and avidity show efficacy in single-dose formulation • Immune response mechanism can be modulated by altering formulation

  21. Acknowledgements Institute for Combinatorial Discovery, Iowa State University

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