无机纳米佐剂的设计及其在人类冠状病毒疫苗免疫增效中的应用

近年来,人类冠状病毒的出现与传播对全球公共卫生防控带来了严重危机和巨大挑战。因此,迫切需要开发广谱的抗冠状病毒疫苗。疫苗一般具有抗原递送与免疫调节两个特点,而佐剂在疫苗免疫增效中发挥着关键作用。随着人们对金属免疫的认识增加,目前除了长期应用的铝佐剂外,其他无机金属元素及其纳米颗粒因其独特的性质发展成为具有潜力的候选佐剂。本文介绍了几种典型的无机纳米颗粒及其在抗人类冠状病毒疫苗佐剂中的应用并提出其设计要点,为后续个性化疫苗与新型无机纳米佐剂的开发提供思路。     

高分子免疫佐剂材料

佐剂是一种添加到疫苗中,使疫苗能够非特异性地增强机体对抗原的特异性免疫应答的物质,是疫苗和免疫治疗的重要组分.为了解决当前市场上小分子和生物制剂佐剂靶向性差、系统暴露度高、生物毒性强等问题,具有免疫刺激活性和生物安全性的高分子材料正在成为免疫佐剂领域的研究热点.在本专论中,我们回顾了近年来发现的具有免疫刺激活性的天然来源或人工合成的高分子佐剂材料,并介绍了用来担载或键合小分子佐剂的高分子材料.提出了“高分子免疫佐剂材料”这一概念,并指出,高分子免疫佐剂材料不仅能够本身作为模式识别受体激动剂而激活免疫系统,具有相比于小分子佐剂更加安全可控的优势,并且可以与小分子佐剂以物理包埋或化学键合的方式相结合,控制抗原和小分子佐剂的体内传输与释放行为,进而增强免疫系统的响应.希望通过本专论的讨论,可以进一步明确对高分子免疫佐剂材料的理解,推动疫苗与免疫治疗这一新兴技术领域的发展.     

DNA纳米机器:梦想照进现实

可进体内治病救人的纳米机器人一直是人们梦寐以求的未来科技和医疗手段.最近,国家纳米科学中心的丁宝全、聂广军等在这个方向取得了重要的突破,成功开发了基于DNA纳米机器的癌症免疫治疗疫苗.他们首先利用DNA折纸术构筑了一个可精确负载抗原和佐剂的管状结构,通过皮下注射递送至淋巴结,经由内吞在树突细胞内涵体内发生pH响应性的锁链打开,暴露抗原和佐剂,从而激活树突细胞,产生抗原特异性的T细胞,有效杀伤肿瘤细胞.该疫苗不仅可以有效抑制肿瘤的生长和复发,还诱导特异性记忆效应,可持续产生特异性的保护.这提供了一个精准递送分子药物的平台,让人看到成功发展纳米机器人的曙光,有望给医学和医疗保健带来重要变革.     

壳聚糖及其衍生物在组织工程中的应用

壳聚糖由于具有良好的生物相容性、生物可降解性以及具有可反应的活性基团,因而在生物、医学等领域具有广泛的研究和应用。随着组织工程学研究的深入,壳聚糖及其衍生物材料作为天然高分子组织工程支架越来越受到重视,综述了近年来国内外壳聚糖及其衍生物在组织工程上的研究和应用情况,包括壳聚糖及其衍生物支架材料的制备方法、壳聚糖的改性以及壳聚糖复合材料等。     

壳聚糖和普朗尼克介导猪白细胞介素-23基因体内表达对PRRSV疫苗的免疫增强效应

猪繁殖和呼吸综合征(PRRS)是一种严重影响养猪业的高度传染性疾病,目前预防这种疾病的疫苗免疫还存在一定缺陷。本研究旨在探索一种有效的佐剂以提高其免疫效力。将猪IL-23基因重组质粒用壳聚糖和普朗尼克材料包裹制成纳米颗粒,命名为VRIL23-CNP-Pluronic。将28日龄小鼠分为两组,分别肌肉注射VRIL23-CNP-Pluronic(实验组)和VR1020-Pluronic(对照组),两组均同时接种PRRSV疫苗,在接种后第0、7、14、28和35天采集血样并分析免疫变化。实验组中PRRSV特异性抗体、IgG1和IgG2a水平、CD4+和CD8+T淋巴细胞数量均极显著高于对照组(p0.01);经qRT-PCR分析,与对照组相比,实验组小鼠的IL-23、TLR1、TLR6、STAT1、IL-10、TNF-α、IL-15和CD62L基因表达水平均极显著上调(p0.01)。结果表明,VRIL23-CNP-Pluronic能促进小鼠对PRRSV疫苗的免疫应答,并为其作为新型PRRSV疫苗佐剂的开发提供理论基础。     

负载壳聚糖及其衍生物的材料表面血液相容性研究进展

壳聚糖及其衍生物具有多种生物活性,基于壳聚糖及其衍生物的材料表面改性是获取各种生物活性表面的重要手段,在生物材料领域显示出广阔的应用前景。为了获得血液相容性良好的壳聚糖改性生物材料表面,可通过引入具备抗凝活性的壳聚糖衍生物或壳聚糖/抗凝剂复合物来抑制壳聚糖固有的促凝作用。本文综述了负载有壳聚糖或其衍生物的材料表面的血液相容性改性方法方面的进展,并根据表面改性方法的不同按照物理改性和化学改性分别对其进行了阐述。     

纳米铝佐剂吸附HBsAg及其免疫学效应的研究

纳米材料用作疫苗佐剂,已受到极大重视[1～4].Kreuter等[5]于1981年首次将纳米材料应用于疫苗佐剂.但直到20世纪90年代初,纳米生物学领域才有了长足进步[6].铝佐剂包括Al(OH)3和AlPO4两种,而Al(OH)3是目前唯一被FDA认证的人用佐剂.本文自制纳米铝佐剂,通过物理吸附HBsAg,以常规铝佐剂为对照,研究Balb/c小鼠和豚鼠对两种佐剂疫苗的体液免疫应答和细胞免疫应答.1实验部分1.1材料、仪器和实验动物HBsAg纯抗原、OPD、辣根过氧化物酶标记的羊抗Balb/c小鼠IgG、ConA、RPMI1640、小牛血清、3H-TdR、氢氧化铝佐剂商业品(2mg/mL);纳米…     

壳聚糖亚胺环钯化合物对碘代苯与丙烯酸反应的催化性能

以苯甲醛或其衍生物对壳聚糖进行接枝改性制得了壳聚糖席夫碱配体,再与Li2PdCl4进行环钯化合成了壳聚糖亚胺环钯化合物催化剂1-10.研究了该类催化剂对碘代苯或碘苯衍生物与丙烯酸偶联反应的催化性能,结果表明该类催化剂具有较好的催化活性和一定的重复使用性能.     

基于石墨烯独特生物界面效应的功能化载体研究进展

二维石墨烯及其衍生物与生物界面的相互作用, 展现出相比于传统维度粒子截然不同的特性, 为功能化医药载体的设计开发提供了潜力策略. 除了优异的电学、热学、光学等性能外, 石墨烯的独特的二维性质, 可以引起细胞更强的应激反应, 包括与细胞膜发生水平摩擦/竖直嵌入/三明治超级结构、选择性被细胞内吞、胞内限域折叠、引发细胞自噬以及隐形活化效应. 基于上述独特界面效应以及理论模拟机制, 对石墨烯进行合理设计, 可在保障安全性的前提下, 满足药物递送、疫苗佐剂、成像传感、光热治疗等需求. 本综述结合课题组近10年在(氧化)石墨烯与生物界面效应、微观作用机理及应用开发方面的系统研究工作, 同时涵盖了国际最新进展, 以期为石墨烯高效、安全体系的设计、构建和应用, 提供理论依据和前瞻性预测.     

基于高分子的疫苗递送系统构建和应用

疫苗是人类用于抵御病原体入侵所开发的一类生物制品,能够有效地控制和预防各种传染性疾病,而现有的一些疫苗由于其成分和结构的缺陷,使得其免疫原性较差,不能很好地诱导机体产生免疫反应,保护机体.因此,如何通过合理设计,使用合适的载体和佐剂构建有效的疫苗递送系统成为学术界和产业界的关注重点.本文回顾了现有疫苗递送系统的进展,并...     

Enhancing the immune response and tumor suppression effect of antitumor vaccines adjuvanted with non-nucleotide small molecule STING agonist

Vaccine adjuvants have been widely used to enhance the immunogenicity of the antigens and elicit long-lasting immune response. However, only few vaccine adjuvants have been approved by the FDA for human use so far. Therefore, there is still an urgent need to develop novel adjuvants for the potential applications in clinical trials. Herein, non-nucleotide small molecule STING agonist di ABZI was employed to construct glycopeptide antigen based vaccines for the first time. Immunological evaluation indicated di ABZI not only enhanced the production of antibodies and T cell immune responses, but also inhibited tumor growth in tumor-bearing mice in glycopeptide-based subunit vaccines. These results indicated that di-ABZI demonstrates a high potential as adjuvant for the development of cancer vaccines.     

Immunological Evaluation of Co‐Assembling a Lipidated Peptide Antigen and Lipophilic Adjuvants: Self‐Adjuvanting Anti‐Breast‐Cancer Vaccine Candidates

Co‐assembling vaccines composed of a lipidated HER2‐derived antigenic CH401 peptide and either a lipophilic adjuvant, Pam₃CSK₄, α‐GalCer, or lipid A 506, were evaluated as breast cancer vaccine candidates. This vaccine design was aimed to inherit both antigen multivalency and antigen‐specific immunostimulation properties, observed in reported self‐adjuvanting vaccine candidates, by using self‐assembly and adjuvant‐conjugated antigens. Under vaccination concentrations, respective lipophilic adjuvants underwent co‐assembly with lipidated CH401, which boosted the anti‐CH401 IgG and IgM production. In particular, α‐GalCer was responsible for the most significant immune activation. Therefore, the newly developed vaccine design enabled the optimization of adjuvants against the antigenic CH401 peptide in a simple preparatory manner. Overall, the co‐assembling vaccine design opens the door for efficient and practical self‐adjuvanting vaccine development.     

pH Responsive Poly(Amino Acid) Nanoparticles as Potent Carrier Adjuvants for Enhancing Cellular Immunity

Adjuvants are widely used in vaccine to improve the protection or treatment efficacy. However, so far they inevitably produce side effects and are hard to induce cellular immunity in practical application. Herein, two kinds of amphiphilic poly(glutamic acid) nanoparticles (α-PGA-F and γ-PGA-F NPs) as nanocarrier adjuvants are fabricated to induce an effective cellular immune response. Amphiphilic PGA are synthesized by grafting phenylalanine ethyl ester to form biodegradable self-assembly nanoadjuvants in a water solution. The model antigen, chicken ovalbumin (OVA), can be loaded into PGA-F NPs (OVA@PGA-F NPs) with the high loading ratio >12%. Moreover, compared with γ-PGA-F NPs, the acidic environment can induce the α-helical secondary structure of α-PGA NPs, promoting membrane fusion and more fast antigen lysosomal escape. Hence, the antigen presenting cells treated with OVA@α-PGA-F NPs show higher secretion of inflammatory cytokines, and higher expression of major biological histocompatibility complex class I and CD80 than those of OVA@γ-PGA-F NPs. Overall, this work indicates that pH responsive α-PGA-F NPs as a carrier adjuvant can effectively improve the ability of cellular immune responses, leading to it being a potent candidate for vaccine applications.     

Nanoformulated Single‐Stranded RNA‐Based Adjuvant with a Coordinative Amphiphile as an Effective Stabilizer: Inducing Humoral Immune Response by Activation of Antigen‐Presenting Cells

As agonists of TLR7/8, single‐stranded RNAs (ssRNAs) are safe and promising adjuvants that do not cause off‐target effects or innate immune overactivation. However, low stability prevents them from mounting sufficient immune responses. This study evaluates the adjuvant effects of ssRNA derived from the cricket paralysis virus intergenic region internal ribosome entry site, formulated as nanoparticles with a coordinative amphiphile, containing a zinc/dipicolylamine complex moiety as a coordinative phosphate binder, as a stabilizer for RNA‐based adjuvants. The nanoformulated ssRNA adjuvant was resistant to enzymatic degradation in vitro and in vivo, and that with a coordinative amphiphile bearing an oleyl group ( CA‐O ) was approximately 100 nm, promoted effective recognition, and improved activation of antigen‐presenting cells, leading to better induction of neutralizing antibodies following single immunization. Hence, CA‐O may increase the efficacy of ssRNA‐based adjuvants, proving useful to meet the urgent need for vaccines during pathogen outbreaks.     

Replacing the Rhamnose-Xylose Moiety of QS-21 with Simpler Terminal Disaccharide Units Attenuates Adjuvant Activity in Truncated Saponin Variants

Adjuvants are key immunostimulatory components in vaccine formulations, which improve the immune response to the co-administered antigen. The saponin natural product QS-21 is one of the most promising immunoadjuvants in the development of vaccines against cancer and infectious diseases but suffers from limitations that have hampered its widespread human use. Previous structure–activity relationship studies have identified simplified saponin variants with truncated carbohydrate chains, but have not focused on the influence of the linear oligosaccharide domain of QS-21 in adjuvant activity. Herein, an expeditious 15-step synthesis of new linear trisaccharide variants of simplified QS-21-derived adjuvants is reported, in which the complex terminal xylose-rhamnose moiety has been replaced with commercially available, simpler lactose and cellobiose disaccharides in a β-anomeric configuration. In vivo immunological evaluation of the synthetic saponins showed attenuated antibody responses, highlighting the negative impact of such carbohydrate modifications on adjuvant activity, which could be associated with higher saponin conformational flexibility.     

Immunological Evaluation of Co-Assembling a Lipidated Peptide Antigen and Lipophilic Adjuvants: Self-Adjuvanting Anti-Breast-Cancer Vaccine Candidates

Co-assembling vaccines composed of a lipidated HER2-derived antigenic CH401 peptide and either a lipophilic adjuvant, Pam₃CSK₄, α-GalCer, or lipid A 506, were evaluated as breast cancer vaccine candidates. This vaccine design was aimed to inherit both antigen multivalency and antigen-specific immunostimulation properties, observed in reported self-adjuvanting vaccine candidates, by using self-assembly and adjuvant-conjugated antigens. Under vaccination concentrations, respective lipophilic adjuvants underwent co-assembly with lipidated CH401, which boosted the anti-CH401 IgG and IgM production. In particular, α-GalCer was responsible for the most significant immune activation. Therefore, the newly developed vaccine design enabled the optimization of adjuvants against the antigenic CH401 peptide in a simple preparatory manner. Overall, the co-assembling vaccine design opens the door for efficient and practical self-adjuvanting vaccine development.     

Computer-Aided Discovery of Potent Broad-Spectrum Vaccine Adjuvants

Adjuvants stimulate the immune system to vigorously respond to a vaccine. While current adjuvants such as aluminum salts and oil-in-water emulsions have been used for decades, they do not generate broad and long-lasting responses in many vaccines. Consequently, more potent adjuvants are needed. Here, using computer-aided molecule design and machine learning, we discovered 2 new, broad-spectrum adjuvants that can boost vaccine responses. Our library containing 46 toll-like receptor (TLR)-targeting agonist ligands were assembled on Au nanoparticles. Comprehensive in vitro, ex vivo and in vivo studies showed both leads promoted dendritic cell activation via multiple TLRs and enhanced antigen presentation to T cells. When used together with tumor-specific antigens to immunize mice against B16-OVA melanoma and 4T1-PD1 breast cancer, both adjuvants unleashed strong immune responses that suppressed tumor growth and lung metastases. Our results show computer-aided design and screening can rapidly uncover potent adjuvants for tackling waning immunity in current vaccines.     

Injectable Biodegradable Chitosan‐Alginate 3D Porous Gel Scaffold for mRNA Vaccine Delivery

mRNA vaccines have proven to be more stable, effective, and specific than protein/peptide‐based vaccines in stimulating both humoral and cellular immune response. However, mRNA's fast degradation rate and low‐transfection efficiency in vivo impede its potential in vaccination. Recent research in gene delivery has focused on nonviral vaccine carriers and either implantable or injectable delivery systems to improve transgene expression in vivo. Here, an injectable chitosan‐alginate gel scaffold for the local delivery of mRNA vaccines is reported. Gel scaffold biodegradation rates and biocompatibility are quantified. Scaffold‐mediated mRNA in vivo transgene expression as well as ovalbumin antigen specific cellular and humoral immune responses are evaluated in vivo. Luciferase reporter protein expression resulting from mRNA lipoplex‐loaded gel scaffolds is five times higher than systemic injection. Compared to systemic injections of naked mRNA or mRNA:lipoplexes, elevated levels of T cell proliferation and IFN‐γ secretion are seen with in vivo scaffold‐mediated mRNA lipoplex delivery. Furthermore, a humoral response (ovalbumin antigen specific IgG levels) is observed as early as week 1 for scaffold‐mediated mRNA lipoplex delivery, while protein‐based immunization did not elicit IgG production until 2 weeks post‐injection. Results suggest that injectable scaffold mRNA vaccine delivery maybe a viable alternative to traditional nucleic acid immunization methods.     

Enhancement of immune response and protection in BALB/c mice immunized with liposomal recombinant major surface glycoprotein of Leishmania (rgp63): The role of bilayer composition

Development of new generation vaccines requires adjuvants to elicit the type and intensity of immune response needed for protection. Liposomes have been shown to be an effective adjuvant formulation. In this study, the role of liposome bilayer composition with different phase transition temperature (T_c) to induce a T helper 1 (Th1) type of immune response and protection against leishmaniasis in BALB/c mice was assessed. Liposome formulations with different bilayer compositions consisting of egg phosphatidylcholine (EPC, T_c < 0 °C), dipalmitoylphosphatidylcholine (DPPC, T_c 41 °C), or distearoylphosphatidylcholine (DSPC, T_c 54 °C) were prepared. All liposomes were contained rgp63 as a recombinant antigen and used to immunize mice subcutaneously 3 times in 3-week intervals. Evaluation of lesion development and splenic parasite burden after challenge with L. major, evaluation of Th1 cytokine (IFN-γ) and Th2 cytokine (IL-4), and titration of IgG isotypes were carried out to assess the type of generated immune response and extent of protection. The results indicated the generated immune response in mice was influenced by the bilayer composition of liposomes, so that mice immunized with liposomes consisting of EPC induced a Th2 type of immune response while liposome consisting of DPPC or DSPC induced Th1 type of immune response. It seems that liposomes prepared with higher Tm phospholipids are suitable formulation to induce Th1 type of immune response and protection, and so might be used for further investigations to develop an effective vaccine against leishmaniasis.     

Enhancement of the effectiveness of electroporation-augmented cutaneous DNA vaccination by a particulate adjuvant

DNA vaccines are attracting increased attention due to multiple advantages over conventional vaccines. Attempts to improve these vaccines focus on enhancing DNA delivery and employing novel immunoadjuvants. Electroporation (EP) has emerged as an effective method for delivering DNA vaccines, significantly enhancing humoral and cellular responses. To further improve EP-augmented DNA vaccination, we used micron-size gold particles as a particulate adjuvant. DNA is not bound, or adsorbed, to the particles. Gold particles were coinjected intradermally with plasmid DNA encoding the hepatitis B virus surface antigen (HBsAg) into mice, both in the absence and presence of noninvasive EP. The particles enhanced the percentage of responding animals, and shortened the time for reaching maximal antibody titers by 2 weeks. Subtyping of the produced antibodies revealed a predominantly Th1-like response which did not change significantly with the absence or presence of particles. The particles likely function as an attractant for antigen-presenting cells (APCs), and probably do not affect EP or antigen expression to a significant extent. We conclude that micron-size gold particles injected intradermally together with DNA followed by EP give rise to an accelerated, potent immune response with a strong cellular component. This method may become important for the development of fast-acting therapeutic and prophylactic vaccines.