Biomaterials to study tolerance immune induction kinetics

摘要 我们计划探索免疫突触的动力学，因为它与耐受的产生有关，使用 由聚合物缩醛葡聚糖(Ac-DEX)制备的纳米/微米粒子(Ps)。之前，我们已经展示了 Ac-DEX颗粒包裹髓鞘碱性蛋白(MBP)治疗对临床评分的影响 地塞米松(DXM)，使用C57BL/6小鼠实验性自身免疫性脑脊髓炎(EAE)模型。 我们继续这项研究，并说明了Ac-DEX颗粒包裹蛋白质脂蛋白(PLP)和 雷帕霉素在SJL复发和缓解的EAE模型中完全降低临床评分至基线 在疾病发作后给药。这两种EAE模型的临床评分降低的程度都是 与其他已发表的抗原特异性EAE治疗方法相比，Ac-DEX颗粒系统的作用更大 已使用粒子系统。我们的粒子系统是独一无二的，因为它依赖于高度可调的聚合物Ac-DEX。 AC-DEX是将药物输送到吞噬细胞的理想药物，因为它对酸敏感，并且具有显著的 吞噬小体在低酸度(~pH 5)时降解增加。除此之外，它还具有可调的降级 价格从几小时到几个月不等，这是与常用聚酯(例如 聚乳酸-羟基乙酸(PLGA))的降解率约为几个月。此外，Ac-DEX是独一无二的 来自聚酯，因为它的降解产物是pH中性的，并且不会改变局部 PH值或对损坏敏感的有效载荷。我们已经证明了AC-DEX粒子的降解率对两者都有影响 传统疫苗的抗体和细胞反应，并假设产生耐受性的效果相似。 因此，我们假设Ac-DEX颗粒通过诱导Treg来促进抗原特异性免疫耐受。 Ac-DEX的环缩醛覆盖影响降解速率，调节免疫突触。我们 有三个具体的目标来解决这个假设。目标1集中在聚合物和颗粒的配方上。 MS代表抗原和模型抗原OVA都将被包裹。粒子参数 类似的大小和装载量将被确定。将制造具有不同环缩醛覆盖度的AC-DEX聚合物 在广泛的时间范围内降解。目的2着重于体外和体内研究，以了解免疫 突触以及它与颗粒降解时间的关系。评估的指标将是 可诱导T调节细胞(ITregs)。此外，我们将使用延迟型超敏反应来优化系统 (DTH)炎症模型。颗粒降解和公差的产生之间的关系将是 最优化。在目标3中，将在MS和Tregs表达的模型中对优化的配方进行评估 还将进行其他免疫学鉴定。这项工作的总体目标是对Ac-Ac进行评估。 地塞米松颗粒系统作为抗原特异性治疗多发性硬化症并了解其释放的影响 耐受剂(如抗原和RAPA)对抗原特异性免疫耐受的产生。

ABSTRACT We plan to explore the kinetics of the immune synapse, as it relates to generation of tolerance, using nano/microparticles (Ps) fabricated from the polymer acetalated dextran (Ac-DEX). Previously, we have shown attenuation of clinical score with treatment of Ac-DEX particles encapsulating myelin basic protein (MBP) and dexamethasone (DXM), using a C57Bl/6 mouse model of experimental autoimmune encephalomyelitis (EAE). We continued this research and illustrated that Ac-DEX particles encapsulating proteolipid protein (PLP) and rapamycin (Rapa) in a SJL relapse and remitting model of EAE completely reduced clinical score to baseline when given after disease onset. The degree of reduction of clinical score for both of these EAE models was greater for the Ac-DEX particles systems than observed in other published antigen-specific EAE treatments that used particle systems. Our particle system is unique because it relies on the highly tunable polymer Ac-DEX. Ac-DEX is ideal for delivery of agents to phagocytic cells because it is acid-sensitive and has significantly increased degradation in the low acid (~pH 5) of the phagosome. In addition to this it has tunable degradation rates that can range from hours to months, which is a unique range from commonly used polyesters (e.g. poly(lactic-co-glycolic acid) (PLGA)) that have degradation on the order of months. Moreover, Ac-DEX is unique from polyesters because its degradation products are pH neutral, and do not have the potential to shift the local pH or damage sensitive payloads. We have shown that Ac-DEX particles have degradation rates that affect both antibody and cellular response for traditional vaccine and hypothesize similar effects for generation of tolerance. Therefore, we hypothesize that Ac-DEX particles promote antigen specific immune tolerance by inducing Tregs and that the cyclic acetal coverage of Ac-DEX impact degradation rate and modulate the immune synapse. We have three specific aims to address this hypothesis. Aim 1 is focused on formulation of the polymer and particles. Both a MS representative antigen as well as the model antigen OVA will be encapsulated. Particle parameters like size and loading will be determined. Ac-DEX polymer with various cyclic acetal coverages will be fabricated to degrade over a broad range of times. Aim 2 focuses on in vitro and in vivo studies to understand the immune synapse and how that relates to particle degradation times. The metrics for evaluation will be generation of inducible T-regulatory cells (iTregs). Furthermore, we will optimize systems using a delayed type hypersensitivity (DTH) model of inflammation. The relationship between particle degradation and generation of tolerance will be optimized. In Aim 3, the optimized formulation will be evaluated in a model of MS and expression of Tregs, as well as other immunological characterizations will be carried out. The overall goal of this work is to evaluate the Ac- DEX particles systems as an antigen-specific treatment for MS and to understand the influence of release of tolerance agents (e.g. antigen and Rapa) on the generation of antigen specific immune tolerance.