中文摘要：研究通过降低poly(I:C)剂量控制poly(I:C)对非免疫旁效应细胞的刺激作用。试验将poly(I:C)组配于PLGA微球表面，并用不同浓度的PEG对该微球表面进行修饰。通过微压溶剂提取作用将模式抗原破伤风菌疫苗装载于PLGA微球内。结果表明，通过将poly(I:C)装配于PEG修饰过的PLGA微球表面能够提高poly(I:C)作为疫苗佐剂的效率和安全性。
 
外文摘要：Biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres are potential vehicles to deliver antigens for vaccination. Because they lack the full capacity to activate professional antigen presenting cells (APCs), combination with an immunostimulatory adjuvant may be considered. A candidate is the synthetic TLR3 ligand polyriboinosinic acid-polyribocytidylic acid, poly(I:C), which drives cell-mediated immunity. However, poly(I:C) has also been linked to the pathogenesis of autoimmunity, as affected by widespread stimulation of non-hematopoietic bystander cells. To address this aspect, we propose to minimize the poly(I:C) dose as well as to control the stimulation of non-immune bystander cells by poly (I:C). To facilitate the maturation of APCs with minimal poly(I:C) doses, we surface-assembled poly(I:C) onto PLGA microspheres. The microspheres' surface was further modified by poly(ethylene glycol) (PEG) coronas with varying PEG-densities. PLGA microspheres loaded with tetanus toxoid (tt) as model antigen were manufactured by microextrusion-based solvent extraction. The negatively charged PLGA(tt) microspheres were coated with polycationic poly(L-lysine) (PLL) polymers, either PLL itself or PEG-grafted PLL (PLL-g-PEG) with varying grafting ratios (g = 2.2 and g = 10.1). Stable surface assembly of poly (I:C) was achieved by subsequent incubation of polymer-coated PLGA microspheres with aqueous poly(I: C) solutions. We evaluated the immunostimulatory potential of such PLGA(tt) microsphere formulations on monocyte-derived dendritic cells (MoDCs) as well as human foreskin fibroblasts (HFFs) as model for non-hematopoietic bystander cells. Formulations with surface-assembled poly(I:C) readily activated MoDCs with respect to the expression of maturation-related surface markers, proinflammatory cytokine secretion and directed migration. When surface-assembled, poly(I:C) enhanced its immunostimulatory activity by more than one order of magnitude as compared to free poly(I:C). On fibroblasts, surface-assembled poly(I:C) upregulated class I MHC but not class II MHC. Phagocytosis of PLGA(tt) microsphere formulations by MoDCs and HFFs remained mostly unaffected by PEG-grafted PLL coatings. In contrast, high concentrations of free poly(I:C) led to a marked drop of microsphere phagocytosis by HFFs. Overall, surface assembly on PEGylated PLGA microspheres holds promise to improve both efficacy and safety of poly(I:C) as vaccine adjuvant.
外文关键词：Adjuvants； Poly(I:C)； Dendritic cells；Fibroblasts；Microspheres；Vaccine formulation
作者：Hafner, AM; Corthesy, B; Textor, M; Merkle, HP
作者单位：苏黎世联邦理工大学
期刊名称：INTERNATIONAL JOURNAL OF PHARMACEUTICS
期刊影响因子：3.994
出版年份：2016
出版刊次：11
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