J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, JG56 BMS Building, P.O. Box 116131, Gainesville, FL 32611-6131, USA.
Acta Biomater. 2010 Sep;6(9):3491-8. doi: 10.1016/j.actbio.2010.03.006. Epub 2010 Mar 11.
Well-designed biomaterial polymer particle-based vaccines will optimally promote immune cell antigen-presenting behavior while minimizing adverse inflammatory responses to the particles and encapsulated drugs or adjuvants. It is important in the design of particle-based vaccines to consider possible harmful effects of immune response on tissue at the vaccination site. Intravital microscopy with rodent dorsal skin window chambers enables in vivo serial observations in the same animal, and such models which have been used to study angiogenesis and macrophage response to implanted biomaterials may also be useful for the development of particle-based vaccines. To our knowledge there have been no reports where intravital microscopy has documented real-time immune cell localization and potentially harmful co-localized tissue effects. In this proof-of-principle study we used fluorescence and spectral imaging intravital microscopy of mouse window chambers to measure macrophage localization and co-localized tissue microvessel hemoglobin saturation changes in response to an immunogenic stimulus from polymer particles loaded with lipopolysaccharide (LPS) serving as a model vaccine/adjuvant system. We observed greater and faster macrophage localization to stronger inflammatory stimuli from LPS-loaded particle doses, a trend of decreased microvessel oxygenation with increased macrophage accumulation and, in an extreme case, complete microvessel collapse accompanied by tissue necrosis. Our technique may be useful for optimizing design of particle-based vaccines and may give insight into the use of hemoglobin saturation as a biomarker of tissue inflammation for clinical investigations of particle-based vaccines.
精心设计的基于生物材料聚合物颗粒的疫苗将最佳地促进免疫细胞的抗原呈递行为，同时将颗粒和包封的药物或佐剂的不良反应最小化。在基于颗粒的疫苗设计中，重要的是要考虑免疫反应对接种部位组织可能产生的有害影响。使用啮齿动物背部皮肤窗室的活体显微镜可以在同一动物体内进行体内连续观察，并且这些模型已被用于研究血管生成和巨噬细胞对植入生物材料的反应，也可能对基于颗粒的疫苗的开发有用。据我们所知，还没有报道活体显微镜记录了免疫细胞的实时定位和潜在的有害组织共定位效应。在这项原理验证研究中，我们使用荧光和光谱活体显微镜对小鼠窗室进行成像，以测量载有脂多糖（LPS）的聚合物颗粒作为模型疫苗/佐剂系统引发免疫反应时巨噬细胞的定位和共定位组织微血管血红蛋白饱和度的变化。我们观察到，来自 LPS 负载颗粒剂量的更强炎症刺激引起的巨噬细胞定位更大且更快，随着巨噬细胞积累的增加，微血管氧合作用呈下降趋势，在极端情况下，微血管完全塌陷并伴有组织坏死。我们的技术可能有助于优化基于颗粒的疫苗的设计，并深入了解血红蛋白饱和度作为组织炎症的生物标志物，用于基于颗粒的疫苗的临床研究。
