黏膜疫苗及其佐剂的研究进展

黏膜疫苗可以通过激活机体黏膜和系统的免疫应答而阻止病原微生物的入侵 ,还可通过诱导抗原特异性的黏膜耐受而选择性地治疗自身免疫性疾病、变态反应性疾病及感染性的免疫病理紊乱等。无论是感染性疾病的预防还是自身免疫性疾病的免疫治疗 ,黏膜疫苗都离不开黏膜佐剂或抗原运输载体。该文从黏膜部位的基本结构出发 ,探讨了设计黏膜疫苗所必需之处 ,重点介绍了黏膜佐剂或抗原运输载体的最新研究状况     

黏膜疫苗及其佐剂的研究进展

黏膜疫苗可以通过激活机体黏膜和系统的免疫应答而阻止病原微生物的入侵，还可通过诱导抗原特异性的黏膜耐受而选择性地治疗自身免疫性疾病、变态反应性疾病及感染性的免疫病理紊乱等。无论是感染性疾病的预防还是自身免疫性疾病的免疫治疗，黏膜疫苗都离不开黏膜佐剂或抗原运输载体。该文从黏膜部位的基本结构出发，探讨了设计黏膜疫苗所必需之处，重点介绍了黏膜佐剂或抗原运输载体的最新研究状况。     

弓形虫黏膜疫苗研究进展

弓形虫主要通过自然感染途径经口感染，引起人和温血动物的弓形虫病。弓形虫可能是世界上人类感染最普遍的寄生虫之一。弓形虫入侵宿主首先要通过黏膜组织的严密防御系统，即黏膜免疫系统，这是机体抗感染的第一道免疫屏障，诱导黏膜免疫应答。在共同黏膜免疫系统（CMIS）的作用下，全身多处黏膜相关淋巴组织（MALT）的免疫活性细胞被激活，黏膜部位产生大量的sIgA抗体，并形成庞大的免疫应答网络，发挥抗虫效应。该文将就近几年来弓形虫抗原诱导的黏膜免疫和黏膜疫苗的研究进行综述。     

肠道黏膜M细胞与微生物相互作用机制研究进展

M细胞是黏膜免疫系统中一种特化的抗原转运细胞,能将抗原由肠腔转运到上皮下的淋巴组织,从而诱导免疫黏膜免疫应答或免疫耐受。因此M细胞被认为是启动黏膜免疫应答的＂门户＂,同时也为许多病原微生物的入侵提供突破口。研究M细胞摄取抗原的机制能为口服疫苗的设计开发提供更有效的途径。本文主要对M细胞的结构功能、M细胞摄取微生物抗原机制等方面作一简要综述。     

结核分枝杆菌EsxV亚单位疫苗黏膜免疫诱导的免疫应答

目的 研究结核分枝杆菌抗原Rv3619c(EsxV)黏膜免疫小鼠诱导的免疫应答水平。方法 PCR法扩增esxV基因克隆入原核表达载体pET28a(+),获得的重组E.coli诱导表达目的蛋白,SDS-PAGE电泳和Western Blot鉴定蛋白的表达,亲和层析法纯化EsxV蛋白。以EsxV和/或联合环二腺苷酸(c-di-AMP)经鼻黏膜免疫BALB/c小鼠,ELISA法检测小鼠特异性抗体水平及亚类,MTS法检测脾细胞增殖,qRT-PCR检测脾和肺脏细胞因子表达水平,ELISA法检测脾细胞因子分泌水平。结果 成功构建EsxV的原核表达载体pET28a(+)-esxV并诱导表达目的蛋白,亲和层析法获得了纯化的重组EsxV蛋白。EsxV经黏膜免疫可诱导显著的体液免疫应答,但诱导的细胞免疫应答水平不高。EsxV与c-di-AMP经黏膜接种可诱导特异性IgG水平增加,EsxV蛋白特异的脾细胞增殖,脾和肺细胞的IFN-γ转录增加。c-di-AMP显著提高EsxV特异的IFN-γ、IL-2、IL-10和IL-17细胞因子分泌,而不诱导炎症因子TNF-α和IL-6表达。结论 EsxV与c-di-AMP佐剂构建的亚单位疫苗可诱导特异性体液和细胞免疫应答,可进一步用于新型结核病亚单位疫苗的研制。     

结核病黏膜疫苗的研究进展北大核心CSCD

呼吸道黏膜免疫是机体抵御结核分枝杆菌(Mycobacterium tuberculosis,MTB)感染的第一道防线,是重要的抗MTB感染的保护性免疫,如何通过黏膜免疫,诱导黏膜免疫系统产生抗MTB感染的特异性免疫,是目前结核病疫苗研究的新方向。本文基于近年来结核病黏膜疫苗的研究,总结了不同类型疫苗的特点、黏膜免疫后的免疫学特性和免疫保护效果,展望了未来结核病黏膜疫苗的研究方向,希望能够对研发更加高效的结核病黏膜疫苗有所启示。     

经口感染弓形虫诱导小鼠黏膜免疫动物模型的建立

目的建立经口感染弓形虫速殖子诱导黏膜免疫的动物模型。方法BALB/c小鼠分别灌胃接种5×103、5×104、5×105、5×106个RH株速殖子,观察小鼠的体况、病理变化;检测肠道分泌型IgA(SIgA)和Peyer’spatches(PP)淋巴细胞及小肠上皮内淋巴细胞(IEL)T细胞亚群的变化。结果经口接种5×104个弓形虫RH株速殖子可使小鼠出现临床症状和病理改变;SIgA水平升高;黏膜诱导部位的CD4 T亚群及效应部位的CD8 T亚群水平升高。结论5×104个弓形虫RH株速殖子灌胃接种小鼠可以诱导机体黏膜免疫应答。     

STAg和CT滴鼻免疫小鼠诱导的刚地弓形虫特异性黏膜及系统免疫应答

刚地弓形虫（Toxoplasma gondii）属专性细胞内寄生性原虫，人群感染极为普遍，全球约20亿人感染，2001—2004年中国人群血清阳性率高达7．88％。弓形虫感染在免疫缺陷、免疫抑制者可引起严重病变，孕期感染可经胎盘垂直传播致先天性弓形虫病。研制安全、有效、价廉的疫苗防治弓形虫感染乃当务之急。机体95％以上的感染发生在黏膜部位，皮下、肌肉接种疫苗不能有效诱导黏膜部位的免疫应答，只有从黏膜部位进行疫苗接种，才能有效预防黏膜感染。     

汉滩病毒核酸疫苗滴鼻及皮肤划痕免疫小鼠的比较研究

目的观察汉滩病毒的DNA疫苗滴鼻及皮肤划痕免疫诱导机体产生的免疫应答,探索汉滩病毒DNA疫苗新的免疫途径。方法采用不同剂量50μg、10μg、1μg的裸露质粒pcDNA3.1B-S1,3分别进行滴鼻及皮肤划痕免疫小鼠,采用ELISA方法分别检测血清及粪便中特异性抗体变化,观察其诱导的系统和黏膜免疫反应的差异。结果用汉滩病毒核酸疫苗免疫小鼠,通过表皮划痕方式其诱导体液免疫在50μg剂量时与滴鼻途径相当,在10μg及1μg低剂量时优于滴鼻途径,但在黏膜免疫方面,其明显不如滴鼻途径。结论滴鼻免疫对特异的黏膜免疫激发作用明显优于皮肤划痕,疫苗的滴鼻免疫途径较皮肤划痕有着明显的优势。     

旋毛虫病疫苗

综述了旋毛虫病减毒活疫苗、天然抗原 (成虫、新生幼虫和肌幼虫粗抗原、ES抗原及纯化抗原 )疫苗、合成肽疫苗、重组抗原疫苗、核酸疫苗及其诱导的保护性免疫应答和预防接种效果 ,讨论了影响疫苗免疫效果的因素 ,如免疫佐剂、接种途径和接种剂量等。     

Using the Nonhuman Primate Model of HCMV to Guide Vaccine Development

The natural history of human cytomegalovirus (HCMV) is inextricably associated with mucosal surfaces. The vast preponderance of primary infections occur following mucosal exposure to infectious virions, and the high seroprevalence of HCMV throughout the world is due to long-term excretion of HCMV in bodily fluids from multiple mucosal sites. Accumulating evidence presents a model where the earliest virus-host interactions following infection dictate the long-term pattern of infection, alter innate immune responses that skew adaptive responses to enable persistence within an immune host, and are essential for reinfection of a host with prior immunity. HCMV has evolved a complex repertoire of viral functions fine-tuned to manipulate the immune environment both locally at the sites of infection and systemically within an infected host. Collectively, viral immune modulation represents a significant impediment for an HCMV vaccine. As HCMV can disseminate beyond mucosal surfaces to reinfect immune hosts, it may not matter whether prior immunity results from prior infection or immunization. A better understanding of the earliest virus-hosts interactions at mucosal surfaces may identify elements of the viral proteome that are especially susceptible to vaccine-mediated disruption and prevent challenge virus from disseminating to distal sites, particularly the maternal-fetal interface.     

Mucosal and systemic adjuvant activity of alphavirus replicon particles

Vaccination represents the most effective control measure in the fight against infectious diseases. Local mucosal immune responses are critical for protection from, and resolution of, infection by numerous mucosal pathogens. Antigen processing across mucosal surfaces is the natural route by which mucosal immunity is generated, as peripheral antigen delivery typically fails to induce mucosal immune responses. However, we demonstrate in this article that mucosal immune responses are evident at multiple mucosal surfaces after parenteral delivery of Venezuelan equine encephalitis virus replicon particles (VRP). Moreover, coinoculation of null VRP (not expressing any transgene) with inactivated influenza virions, or ovalbumin, resulted in a significant increase in antigen-specific systemic IgG and fecal IgA antibodies, compared with antigen alone. Pretreatment of VRP with UV light largely abrogated this adjuvant effect. These results demonstrate that alphavirus replicon particles possess intrinsic systemic and mucosal adjuvant activity and suggest that VRP RNA replication is the trigger for this activity. We feel that these observations and the continued experimentation they stimulate will ultimately define the specific components of an alternative pathway for the induction of mucosal immunity, and if the activity is evident in humans, will enable new possibilities for safe and inexpensive subunit and inactivated vaccines.     

Herpesvirus Exploitation of Host Immune Inhibitory Pathways

Herpesviruses employ a plethora of mechanisms to circumvent clearance by host immune responses. A key feature of mammalian immune systems is the employment of regulatory pathways that limit immune responsiveness. The primary functions of these mechanisms are to control autoimmunity and limit exuberant responses to harmless antigen in mucosal surfaces. However, such pathways can be exploited by viral pathogens to enable acute infection, persistence and dissemination. Herein, we outline the current understanding of inhibitory pathways in modulating antiviral immunity during herpesvirus infections in vivo and discuss strategies employed by herpesviruses to exploit these pathways to limit host antiviral immunity.     

Epithelial Cell Regulation of Allergic Diseases

Allergic diseases, which have escalated in prevalence in recent years, arise as a result of maladaptive immune responses to ubiquitous environmental stimuli. Why only certain individuals mount inappropriate type 2 immune responses to these otherwise harmless allergens has remained an unanswered question. Mounting evidence suggests that the epithelium, by sensing its environment, is the central regulator of allergic diseases. Once considered to be a passive barrier to allergens, epithelial cells at mucosal surfaces are now considered to be the cornerstone of the allergic diathesis. Beyond their function as maintaining barrier at mucosal surfaces, mucosal epithelial cells through the secretion of mediators like IL-25, IL-33, and TSLP control the fate of downstream allergic immune responses. In this review, we will discuss the advances in recent years regarding the process of allergen recognition and secretion of soluble mediators by epithelial cells that shape the development of the allergic response.     

Neutralizing antibodies in mucosal secretions: IgG or IgA?

The mucosal immune response to HIV weighs in heavily on the battle against it, as the majority of infections occur via the mucosal route. The antibody response in the mucosae, specifically the genital tract, is characterized by binding and, in some studies, neutralizing HIV-specific IgG and IgA antibodies. Ample evidence, however, points to discrepancies and difficulties in the detection of HIV-specific IgA in HIV-positive subjects, and an even more pronounced divide surfaces in studies done with individuals exposed to HIV, but uninfected. Reports in the literature detail HIV-specific (in some cases, neutralizing) IgA antibodies, in the absence of specific IgG, in the serum and mucosal secretions of virus-exposed, seronegative subjects; this has given rise to speculation that HIV-specific IgA provides a protective immune response to the virus in high-risk individuals who remain seronegative. Contradictory results, however, describe the absence of both IgA and IgG HIV antibodies in the mucosal secretions of similar cohorts. Considering the importance of the antibody response to ascertaining the correlates of HIV immunity, as well as on vaccine research and development, this review addresses the relevant studies and their implications.     

Human IL-3/GM-CSF knock-in mice support human alveolar macrophage development and human immune responses in the lung

Mice with a functional human immune system have the potential to allow in vivo studies of human infectious diseases and to enable vaccine testing. To this end, mice need to fully support the development of human immune cells, allow infection with human pathogens, and be capable of mounting effective human immune responses. A major limitation of humanized mice is the poor development and function of human myeloid cells and the absence of human immune responses at mucosal surfaces, such as the lung. To overcome this, we generated human IL-3/GM-CSF knock-in (hIL-3/GM-CSF KI) mice. These mice faithfully expressed human GM-CSF and IL-3 and developed pulmonary alveolar proteinosis because of elimination of mouse GM-CSF. We demonstrate that hIL-3/GM-CSF KI mice engrafted with human CD34(+) hematopoietic cells had improved human myeloid cell reconstitution in the lung. In particular, hIL-3/GM-CSF KI mice supported the development of human alveolar macrophages that partially rescued the pulmonary alveolar proteinosis syndrome. Moreover, human alveolar macrophages mounted correlates of a human innate immune response against influenza virus. The hIL-3/GM-CSF KI mice represent a unique mouse model that permits the study of human mucosal immune responses to lung pathogens.     

Ex vivo development of functional human lymph node and bronchus-associated lymphoid tissue

We introduce a novel in vivo model of human mucosal immunity, based on the implantation of human fetal bronchial mucosa and autologous peribronchial lymph node (PLN) in the severe combined immunodeficiency (SCID) mouse. In the SCID host, human fetal bronchi implanted alone retain macrophages and mast cells but lose T cells. In contrast, fetal bronchi co-implanted with PLN contain, in addition to macrophages and mast cells, numerous T cells and B cells, often clustered in intramucosal bronchus-associated lymphoid tissue (BALT). Functionally, bronchus-PLN cografts are able to mount robust alphabeta and gammadelta T-cell-mediated immune responses to Pseudomonas aeruginosa and 3,4-epoxy-3-methyl-1-butyl-diphosphate challenges. No other autologous lymphoid organ (bone marrow, thymus, liver) allows for BALT development in co-implanted bronchi, which suggests special ontogenetic and functional relations between extramucosal PLN and intramucosal BALT. Overall, the bronchus-PLN cograft appears as a promising model for human bronchial immune development and function. Our study is the first to document long-term ex vivo maintenance of functional human lymph nodes as native appendices to mucosal tissue. Our results, therefore, suggest a simple strategy for developing similar experimental models of human immune function in other mucosae.     

Mucosal Immunity and the Onset of Allergic Disease

Mucosal barriers encounter an environment that is rich in pathogens that possess mechanisms for invading mucosal tissues. These barriers also encounter innocuous antigens, such as foods, airborne antigens, and microbiota. The mucosa has developed a sophisticated immune system that can mount robust immune responses against pathogenic antigens, while maintaining mucosal tolerance against non-pathogenic antigens. Accumulating evidence indicates that the mucosal epithelium, dendritic cells, and a subtype of T cells with regulatory properties play important roles in the development and maintenance of mucosal tolerance. Moreover, the micribiota also contribute to regulating the mucosal immune system. A failure to develop or the breakdown of mucosal tolerance can result in allergic diseases, such as food allergy and asthma. By taking advantage of the unique characteristics of the mucosal immune system, strategies that induce regulatory cells in vivo and, thereby, reconstitute mucosal tolerance may be used to develop novel therapies that are suitable for treating or preventing of allergic diseases.     

Induction of immune responses to SIV antigens by mucosally administered vaccines.

In an attempt to develop an immunization strategy to induce mucosal and circulatory antibodies against SIV antigens, we have investigated the potential of attenuated recombinant vaccinia virus to deliver SIV antigens (gp160 of SIVmac239) to mucosal surfaces of mice. After systemic or mucosal (intragastric, intranasal, or intrarectal) immunization with vaccinia virus-SIV Env recombinants the immune responses against the envelope glycoprotein of SIV, as well as against vaccinia virus antigens, were assessed by ELISA of serum, saliva, and intestinal and vaginal secretions. All immunization routes induced specific antibody titers against gp160 in both serum and external secretions. Recall responses against SIV were found to be acquired after administration of SIVmac239 Env and Gag antigens in a virus-like particle (VLP) form by the same mucosal routes as those used for the priming with recombinant vaccinia virus. The results obtained demonstrate the potential of vaccinia virus recombinants to elicit a primary immune response at mucosal surfaces, which could be enhanced by delivering the same antigen in the form of VLPs.     

Challenges in Mucosal HIV Vaccine Development: Lessons from Non-Human Primate Models

An efficacious HIV vaccine is urgently needed to curb the AIDS pandemic. The modest protection elicited in the phase III clinical vaccine trial in Thailand provided hope that this goal might be achieved. However, new approaches are necessary for further advances. As HIV is transmitted primarily across mucosal surfaces, development of immunity at these sites is critical, but few clinical vaccine trials have targeted these sites or assessed vaccine-elicited mucosal immune responses. Pre-clinical studies in non-human primate models have facilitated progress in mucosal vaccine development by evaluating candidate vaccine approaches, developing methodologies for collecting and assessing mucosal samples, and providing clues to immune correlates of protective immunity for further investigation. In this review we have focused on non-human primate studies which have provided important information for future design of vaccine strategies, targeting of mucosal inductive sites, and assessment of mucosal immunity. Knowledge gained in these studies will inform mucosal vaccine design and evaluation in human clinical trials.