Adoptive transfer of dendritic cells isolated from helminth-infected mice enhanced T regulatory cell responses in airway allergic inflammation

Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. Moreover, we found that adoptive transfer of dendritic cells (DCs) from inhibited mice showed a similar inhibitory effect on allergy, suggesting a critical role of DCs in SJ-infected mediated inhibition of allergy. In this study, we further examined the mechanism by which DCs contribute to inhibition of allergy. Our results showed that DCs from SJ-infected mice (SJDCs) produced significantly higher levels of IL-10 compared to those from naive control mice (NDCs). Adoptive transfer of SJDCs, unlike NDCs, significantly increased CD4+CD25+Foxp3+ T cells and CD4+CD25+IL-10+ T cells regulatory T-cell responses in vivo. This was correlated with significantly reduced production of IL-4 and IL-5 by CD4+ T cells, eotaxin in lung tissues and reduced airway allergic inflammation in the SJDC recipients following allergen sensitization and challenge. These data suggest that helminth infection may induce tolerogenic DCs that can inhibit the development of airway allergic inflammation through enhancing T regulatory cell responses.     

日本血吸虫感染鼠树突状细胞对哮喘抑制作用的实验研究

目的通过过继转移日本血吸虫感染鼠树突状细胞(DC),探讨DC在抑制过敏性哮喘中的作用及机制。方法用CD11c 磁珠分离纯化日本血吸虫感染鼠及正常鼠DC亚群CD11c 细胞。将15只BALB/c小鼠随机分为3组,A组为过继转移日本血吸虫感染鼠DC并诱发过敏性哮喘组,B组为过继转移正常鼠DC并诱发过敏性哮喘组,C组为单纯过敏性哮喘组。A、B两组小鼠经尾静脉过继转移1×106DC,2 h后A、B、C 3组均开始诱发哮喘。4周后处死小鼠,收集肺泡灌洗液,检测细胞因子IL-4I、L-5及IFN-γ水平;取小鼠肺组织作病理切片,观察其炎症变化。结果与B、C组比较,A组肺部炎症明显减轻,按Underwood标准,A、B、C 3组总评分分别为5.00±1.58、11.40±2.07和13.20±2.86,差异有统计学意义(P<0.05)。A、B、C组小鼠肺泡灌洗液IL-4水平分别为(23.25±1.57)pg/ml、(40.70±3.28)pg/ml和(65.23±4.84)pg/ml,差异有统计学意义(P<0.05);IL-5水平分别为(16.20±4.11)pg/ml、(41.41±7.14)pg/ml和(64.75±16.96)pg/ml,IFN-γ水平分别为(6.60±2.34)pg/ml(、6.94±2.19)pg/ml和(5.87±2.44)pg/ml,差异无统计学意义(P>0.05)。结论日本血吸虫感染鼠DC通过影响受体鼠Th2细胞因子的分泌明显抑制过敏性哮喘的发生。     

The role of dendritic cells in immune regulation and allergic airway inflammation

Abstract: Dendritic cells (DC) are potent antigen presenting cells that display an extraordinary capacity to present antigen to naïve T‐cells and initiate primary immune responses. In the context of the lung and upper airway it is clear that DC play a key role in the regulation of adaptive immune responses to inhaled antigen. DC are particularly sensitive to signals derived from microbes, allergens and the airway tissue microenvironment. By the nature of the signals they provide at the time of antigen presentation, DC can polarize naïve T‐cells into either T‐helper type 1 (Th1) or Th2 effector cells, and are increasingly recognized as having a central role in the establishment of T‐cell memory and peripheral immune tolerance. DC form a network within the upper airway and lung, and are rapidly recruited from the circulation in response to a variety of proinflammatory stimuli. Studies using animal models have highlighted the role of DC in both the initiation and maintenance of allergic airway inflammation. In early childhood, human DC are functionally immature, and this is thought to contribute to the development of allergic sensitization in those children who are genetically at risk for the development of atopy. Increased numbers of airway mucosal DC are found in both allergic rhinitis and asthma, while studies of blood‐derived DC have emphasized important differences between the function of DC from atopic and normal individuals. This article reviews recent information on the involvement of DC in allergic airway disease, and the mechanisms by which DC could be exploited as targets for therapy in asthma and allergic rhinitis.     

Effective treatment of allergic airway inflammation with Helicobacter pylori immunomodulators requires BATF3-dependent dendritic cells and IL-10

The prevalence of allergic asthma and other atopic diseases has reached epidemic proportions in large parts of the developed world. The gradual loss of the human indigenous microbiota has been held responsible for this trend. The bacterial pathogen Helicobacter pylori is a constituent of the normal gastric microbiota whose presence has been inversely linked to allergy and asthma in humans and experimental models. Here we show that oral or i.p. tolerization with H. pylori extract prevents the airway hyperresponsiveness, bronchoalveolar eosinophilia, pulmonary inflammation, and Th2 cytokine production that are hallmarks of allergen-induced asthma in mice. Asthma protection is not conferred by extracts from other enteropathogens and requires a heat-sensitive H. pylori component and the DC-intrinsic production of IL-10. The basic leucine zipper ATF-like 3 (BATF3)-dependent CD103⁺CD11b⁻ dendritic cell lineage is enriched in the lungs of protected mice and strictly required for protection. Two H. pylori persistence determinants, the γ-glutamyl-transpeptidase GGT and the vacuolating cytotoxin VacA, are required and sufficient for asthma protection and can be administered in purified form to prevent asthma. In conclusion, we provide preclinical evidence for the concept that the immunomodulatory properties of H. pylori can be exploited for tolerization strategies aiming to prevent allergen-induced asthma.The prevalence of asthma and other allergic diseases has increased steadily in the course of the second half of the 20th century in both adult and pediatric, developed and developing populations (1). The lack of early childhood infections or microbial exposure due to improved sanitation, and the gradual loss of the indigenous microbiota have alternately been proposed to account for this major public health trend (2, 3). Epidemiological and experimental studies have consistently shown a strong inverse association of chronic infection with the human gastric bacterial pathogen Helicobacter pylori with the risk of developing allergic asthma (4–9). Chronic infection with H. pylori is less common in allergic individuals presenting with asthma, hay fever, or eczema than in the general population; this is especially true in children and in patients with early-onset disease (4–8). We have reported earlier that experimental infection of C57/BL6 mice with a mouse-colonizing human isolate of H. pylori confers robust protection against allergen-induced asthma, with particularly strong protective effects observed upon early-life exposure (9). Asthma protection could be attributed to H. pylori-specific tolerogenic reprogramming of dendritic cells in vitro and in vivo and to the induction of highly suppressive regulatory T cells (9, 10). Despite its striking immunomodulatory properties (11) and remarkable inverse link to various allergic diseases, the use of live H. pylori as a therapeutic intervention or preventive measure is unattractive due to the well-documented carcinogenic potential of chronic infection with this organism. H. pylori induces gastric and duodenal ulcers (12), and is also widely accepted to be the leading cause of gastric adenocarcinoma (13). Here, we have devised a strategy of H. pylori-specific tolerization that harnesses the bacteria’s immunomodulatory properties for the prevention of asthma while avoiding the risks associated with live infection and have elucidated several key determinants of asthma protection in both the bacteria and the host.     

CD8α− DC is the major DC subset which mediates inhibition of allergic responses by Schistosoma infection

Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. We recently reported that DCs played an important role in SJ infection‐mediated inhibition of allergy, which was associated with enhanced IL‐10 and T regulatory cell responses. Here, we further compared the role of CD8α⁺ DC and CD8α^? DC subsets for the inhibitory effect. We sorted CD8α⁺ DC (SJCD8α⁺ DC) and CD8α^? DC (SJCD8α^? DC) from SJ‐infected mice and tested their ability to modulate allergic responses in vivo. The data showed that the adoptive transfer of SJCD8α^? DC was much more efficient than SJCD8α⁺ DC for the suppression of allergic airway eosinophilia, mucus overproduction, antigen‐specific IgE responses, and Th2 cytokines (IL‐4 and IL‐5). More importantly, we found that the transfer of SJCD8α^? DC, but not SJCD8α⁺ DC, significantly increased IL‐10 and TGF‐β production following OVA exposure. As control, the transfer of DC subsets from naïve mice had no significant effect on allergic inflammation. In addition, SJCD8α‐DC expressed significantly higher IL‐10 but lower IL‐12, CD80 and CD86 than SJCD8α⁺ DC, fitting a tolerogenic phenotype. The results suggest that CD8α^? DC is the predominant DC subset which is involved in the parasitic infection‐mediated inhibition of allergic inflammation and possibly through enhancing immunomodulatory cytokine (IL‐10 and TGF‐β) production.     

树突状细胞多价核酸疫苗抗血吸虫感染作用及机制研究

目的 探讨基因转染对树突状细胞(DC)功能的影响及DC多价核酸疫苗抗血吸虫感染作用及机制。方法 利用脂质体介导的基因转染技术将Sj26、Sj23和Sj14基因分别转染DC,流式细胞术(FCM)检测DC摄取抗原能力,混合淋巴细胞反应(MLR)检测DC对同种异体T淋巴细胞的刺激作用。Sj26、Sj23和Sj14基因转染DC分别和联合免疫BALB/c小鼠3次,末次免疫2周后,每只小鼠感染日本血吸虫尾蚴40条,小鼠感染血吸虫6周后,计数成虫和虫卵。ELISA法检测血清特异性IgG、血清干扰素-γ(IFN-γ)和白细胞介素-4(IL-4)及脾淋巴细胞培养上清IFN-γ、IL-4水平,噻唑蓝(MTT)法检测脾淋巴细胞的增殖。结果 与真核表达载体pcDNA3转染DC和未处理DC相比较,基因转染DC摄取抗原的荧光强度明显降低(P<0.01),对同种异体T淋巴细胞的刺激指数明显升高(P<0.01)。各免疫组小鼠诱导的减虫率和减卵率均高于对照组(P<0.01),而基因转染DC联合免疫组小鼠抗血吸虫感染作用高于单一基因转染DC免疫组(P<0.001)。基因转染DC免疫组小鼠末次免疫2周后血清特异性IgG水平较免疫前显著升高(P<0.05),血清IFN-γ水平明显升高(P<0.01),而血清IL-4的水平无明显变化。与对照组比较,基因转染DC免疫组小鼠脾淋巴细胞经ConA和SEA刺激后培养上清IFN-γ水平显著增高,IL-4水平显著降低,刺激指数(SI)显著增高(P<0.001)。结论 基因转染能促进DC的成熟,增强DC的活性,DC多价核酸疫苗可增强抗血吸虫感染作用,其作用机制以Th1型免疫应答为主。     

日本血吸虫感染对OVA诱导的小鼠过敏反应的影响

目的研究蠕虫感染对过敏性哮喘的影响。方法将15只BALB/c小鼠随机分成3组,每组5只。Ⅰ组为血吸虫感染后OVA致敏组,Ⅱ组为单纯OVA致敏组,Ⅲ组为正常对照组。Ⅰ组小鼠首先建立日本血吸虫感染模型,于感染后第57~84d,与Ⅱ组小鼠一起以OVA(卵清白蛋白)诱导建立过敏性哮喘模型,第85d剖杀全部小鼠,收集脾脏、肺脏和支气管肺泡灌洗液。制备支气管肺泡灌洗液涂片以计数其中各类细胞;制备肺组织切片以检查肺部病理变化;培养脾细胞以检测培养上清中相关细胞因子水平。另外,还要检测支气管肺泡灌洗液中相关细胞因子水平。结果与Ⅱ组相比,Ⅰ组小鼠肺部嗜酸粒细胞数量显著减少(P<0.05),肺部炎症明显减轻(P<0.05),支气管肺泡灌洗液和脾细胞培养上清中IL-4和IL-5水平均降低(P<0.05),而IFN-γ水平无明显改变(P>0.05)。结论日本血吸虫感染对OVA诱导的过敏性哮喘有抑制作用。     

New insights into the hygiene hypothesis in allergic diseases

There is convincing evidence from both human and animal studies suggesting that the infant intestinal microbiota plays an important role in regulating immune responses associated with the development of allergic diseases. To date there are, however, still no definite bacterial taxa or particular subsets of the microbiota that have been consistently associated with allergic diseases, which is mainly attributable to the methodological dissimilarities between studies. As such there is a need to apply different methodological concepts to enhance a deeper and more refined understanding of the relationship between the gut microbiota and allergies. Within our recent studies we reported that colonization by clostridia in early infancy increased the risk of atopic dermatitis. Using subsequent mediation analysis, we demonstrated that birth mode and having older siblings strongly impacted the infant microbiota which in turn affected the risk of atopic dermatitis. The results of these mediation analyses contributed stronger evidence for a causal link of birth mode and birth order on allergy risk through modulation of the microbiota composition.     

Defect of protective immunity to Schistosoma mansoni infection in Mongolian gerbils involves limited recruitment of dendritic cells in the vaccinated skin

In Mongolian gerbils, Meriones unguiculatus, the attenuated Schistosoma mansoni vaccine, is known to induce marginal or no resistance to a homologous infection. To clarify the base of defective acquisition of the resistance, we have focused on the induction phase of protective immunity to S. mansoni, i.e. cellular responses in the skin and skin-draining lymph nodes (SLN). Percutaneous exposure to normal or ultraviolet (18mJ/cm2)-attenuated cercariae induced comparable increases in SLN leucocyte counts, in contrast to other attenuated schistosome vaccine models in rodents where attenuated parasites induce more notable increases in SLN leucocyte counts than normal ones. Using serial sections, it was demonstrated that greater numbers of attenuated larvae remained for a longer period in the exposed skin than normal ones. Correlated with cellular responses in the SLN, attenuated and normal schistosomes elicited a comparable degree of response of epidermal Langerhans' cells/putative dermal dendritic cells that were visualized by immunohistochemistry using a monoclonal antibody to a gerbil major histocompatibility complex class II molecule (HUSM-M.g.30). It is speculated that in Mongolian gerbils limited recruitment of dendritic cells around attenuated S. mansoni larvae, at least partially, contribute to defective induction of protective immunity by the attenuated vaccine.     

Helminth Infection and Type 1 Diabetes

The increasing incidence of type 1 diabetes (T1D) and autoimmune diseases in industrialized countries cannot be exclusively explained by genetic factors. Human epidemiological studies and animal experimental data provide accumulating evidence for the role of environmental factors, such as infections, in the regulation of allergy and autoimmune diseases. The hygiene hypothesis has formally provided a rationale for these observations, suggesting that our co-evolution with pathogens has contributed to the shaping of the present-day human immune system. Therefore, improved sanitation, together with infection control, has removed immunoregulatory mechanisms on which our immune system may depend. Helminths are multicellular organisms that have developed a wide range of strategies to manipulate the host immune system to survive and complete their reproductive cycles successfully. Immunity to helminths involves profound changes in both the innate and adaptive immune compartments, which can have a protective effect in inflammation and autoimmunity. Recently, helminth-derived antigens and molecules have been tested in vitro and in vivo to explore possible applications in the treatment of inflammatory and autoimmune diseases, including T1D. This exciting approach presents numerous challenges that will need to be addressed before it can reach safe clinical application. This review outlines basic insight into the ability of helminths to modulate the onset and progression of T1D, and frames some of the challenges that helminth-derived therapies may face in the context of clinical translation.     

New insights into the hygiene hypothesis in allergic diseases: Mediation of sibling and birth mode effects by the gut microbiota

There is convincing evidence from both human and animal studies suggesting that the infant intestinal microbiota plays an important role in regulating immune responses associated with the development of allergic diseases. To date there are, however, still no definite bacterial taxa or particular subsets of the microbiota that have been consistently associated with allergic diseases, which is mainly attributable to the methodological dissimilarities between studies. As such there is a need to apply different methodological concepts to enhance a deeper and more refined understanding of the relationship between the gut microbiota and allergies. Within our recent studies we reported that colonization by clostridia in early infancy increased the risk of atopic dermatitis. Using subsequent mediation analysis, we demonstrated that birth mode and having older siblings strongly impacted the infant microbiota which in turn affected the risk of atopic dermatitis. The results of these mediation analyses contributed stronger evidence for a causal link of birth mode and birth order on allergy risk through modulation of the microbiota composition.     

Isolated Schistosoma mansoni eggs prevent allergic airway inflammation

Chronic helminth infection with Schistosoma (S.) mansoni protects against allergic airway inflammation (AAI) in mice and is associated with reduced Th2 responses to inhaled allergens in humans, despite the presence of schistosome‐specific Th2 immunity. Schistosome eggs strongly induce type 2 immunity and allow to study the dynamics of Th2 versus regulatory responses in the absence of worms. Treatment with isolated S. mansoni eggs by i.p. injection prior to induction of AAI to ovalbumin (OVA)/alum led to significantly reduced AAI as assessed by less BAL and lung eosinophilia, less cellular influx into lung tissue, less OVA‐specific Th2 cytokines in lungs and lung‐draining mediastinal lymph nodes and less circulating allergen‐specific IgG1 and IgE antibodies. While OVA‐specific Th2 responses were inhibited, treatment induced a strong systemic Th2 response to the eggs. The protective effect of S. mansoni eggs was unaltered in μMT mice lacking mature (B2) B cells and unaffected by Treg cell depletion using anti‐CD25 blocking antibodies during egg treatment and allergic sensitization. Notably, prophylactic egg treatment resulted in a reduced influx of pro‐inflammatory, monocyte‐derived dendritic cells into lung tissue of allergic mice following challenge. Altogether, S. mansoni eggs can protect against the development of AAI, despite strong egg‐specific Th2 responses.     

日本血吸虫感染过程中糖酵解途径对调节性T细胞产生的影响

目的 探索日本血吸虫感染过程中糖酵解途径对小鼠调节性T（Treg）细胞数量和功能的影响。方法 建立日本血吸虫感染小鼠模型,用糖酵解抑制剂2?Deoxy?D?glucose（2DG）或PBS对日本血吸虫感染小鼠进行6次腹腔注射后,分离脾脏细胞和肠系膜淋巴结,采用流式细胞术（FCM）检测分离得到的细胞中Glut1+CD4+ T细胞以及Treg细胞比例。结果 未感染组小鼠脾脏（43.58%±2.50% vs. 21.15%±0.96%;t = 8.834,P < 0.01）和肠系膜淋巴结中Glut1+CD4+ T细胞比例（38.97%±1.97% vs. 28.40%±2.11%;t = 3.662,P < 0.05）均显著高于感染日本血吸虫8周小鼠,但未感染组小鼠脾脏（6.83%±0.21% vs. 13.30%±0.35%;t = 15.65,P < 0.01）和肠系膜淋巴结中Treg细胞比例（8.26%±0.15% vs. 14.37%±0.44%;t = 13.14,P < 0.01）均显著低于感染组小鼠。感染小鼠给与2DG腹腔注射后,脾脏（15.50%± 0.76% vs. 13.07%±0.15%;t = 3.130,P < 0.05）和肠系膜淋巴结中Treg细胞比例（17.00%±0.41% vs. 13.83%±0.18%;t = 6.947,P < 0.01）显著高于给与PBS注射小鼠。结论 糖酵解途径抑制了日本血吸虫感染小鼠Treg细胞分化。     

过继转移日本血吸虫感染鼠DC亚群对过敏性哮喘肺组织病理改变及CCL2表达的抑制作用

目的通过过继转移日本血吸虫感染鼠树突状细胞(DC)亚群,探讨DC亚群在抑制过敏性哮喘中的作用。方法用CD8α和CD11c磁珠分离纯化日本血吸虫感染鼠DC亚群,分别获得CD8α-CD11c+DC和CD8α+CD11c+DC。将24只BALB/c小鼠随机分为4组:A组为健康对照组,CD8α-DC/OVA组(B组)为过继转移日本血吸虫感染鼠DCCD8α-CD11c+亚群并诱发过敏性哮喘组,CD8α+DC/OVA组(C组)为过继转移日本血吸虫感染鼠DC CD8α+CD11c+亚群并诱发过敏性哮喘组,OVA组(D组)为单纯诱发过敏性哮喘组。B、C两组小鼠分别经尾静脉过继转移5×105 DC亚群,1h后B、C和D组均开始诱发哮喘。4周后处死小鼠,取左肺做病理切片和免疫组织化学染色,观察炎症变化,检测肺组织CCL2表达情况。结果与C组和D组比较,B组肺部炎症显著减轻,按照Underwood标准,A、B、C和D等4组总评分分别为0、7.67±2.34、11.17±1.47和11.75±2.22,差异有统计学意义(P<0.05)。4组小鼠肺组织CCL2平均吸光度值分别为0.0327±0.0154、0.3967±0.0250、0.5274±0.0281和0.5631±0.0282,差异有统计学意义(P<0.05)。结论日本血吸虫感染鼠CD8α-CD11c+DC亚群对过敏性哮喘小鼠肺组织病理改变及CCL2的表达有抑制作用。     

Cyclic AMP concentrations in dendritic cells induce and regulate Th2 immunity and allergic asthma

The inductive role of dendritic cells (DC) in Th2 differentiation has not been fully defined. We addressed this gap in knowledge by focusing on signaling events mediated by the heterotrimeric GTP binding proteins Gαs, and Gαi, which respectively stimulate and inhibit the activation of adenylyl cyclases and the synthesis of cAMP. We show here that deletion of Gnas, the gene that encodes Gαs in mouse CD11c⁺ cells (Gnas^ΔCD11c mice), and the accompanying decrease in cAMP provoke Th2 polarization and yields a prominent allergic phenotype, whereas increases in cAMP inhibit these responses. The effects of cAMP on DC can be demonstrated in vitro and in vivo and are mediated via PKA. Certain gene products made by Gnas^ΔCD11c DC affect the Th2 bias. These findings imply that G protein-coupled receptors, the physiological regulators of Gαs and Gαi activation and cAMP formation, act via PKA to regulate Th bias in DC and in turn, Th2-mediated immunopathologies.The induction of Th cell response requires antigen-presenting cells (APC), especially dendritic cells (DC), but the mechanisms for this induction have not been fully elucidated (1, 2). Because DC do not produce IL-4, which is mandatory for GATA3 induction and Th2 cell differentiation (3, 4), other cell types may be involved in Th2 responses (1, 5, 6), including basophils (7), epithelial cells (8), and innate lymphoid cells (ILC), especially ILC group 2 (ILC2) (9). ILCs are a multifunctional group of cells that are able to secrete immunoregulatory cytokines that affect immune responses. They reside at mucosal surfaces, where they are exposed to microbial or environmental stimulation (10). Such cells can secrete IL-4 or alarmins, including IL-25, IL-33, and TSLP (epithelial cells), which support Th2 differentiation (11). Other DC-derived inducers of Th2-differentiation are the Notch ligand Jagged 1 (12) and the interaction between OX40 and OX40L (13). However, little is known regarding the signaling networks that provoke DC to induce Th2 immunity.Pharmacological inhibition of cyclic nucleotide phosphodiesterase 4 (PDE4), which is highly expressed in DC, can produce improvement in animal models of inflammation and autoimmunity and can suppress human Th1-polarizing capacity by increasing cAMP concentrations (14, 15). Based on these findings and our previous work that identified a role for cAMP in DC in Th17 induction (16), we hypothesized that cAMP regulates DC and affects Th differentiation bias. To test this hypothesis, we studied the regulation of DC activity by heterotrimeric (αβγ) GTP binding proteins that regulate cAMP synthesis through their modulation of the activity of adenylyl cyclases (ACs): Gαs, which stimulates AC activity, and Gαi, which inhibits membrane AC activity.In the current studies, we engineered mice that have a CD11c-specific deletion of Gnas (CD11c-Cre Gnas^fl/fl, i.e., Gnas^ΔCD11c), the gene that encodes Gαs (17). We found that cAMP accumulation is much less in response to Gαs activation of CD11c⁺ cells from these mice than from littermate (fl/fl) controls. Unexpectedly, the Gnas^ΔCD11c mice display a striking phenotype: They develop spontaneous Th2 immunity even though these mice have a C57BL/6 genetic background, which is biased to Th1 immunity (18). Consequently, these mice develop later airway inflammation that is consistent with allergic asthma (19). Bone marrow (BM)-derived DC (BMDC) from the Gnas^ΔCD11c mice display a pro-Th2 phenotype (i.e., induce a Th2 response when cocultured with CD4 T cells), which can be prevented by treatment with a cAMP analog. Additional studies show that the cAMP effector protein kinase A (PKA) and molecules whose expression is regulated by cAMP play a key role in the induction of the Th2-biased phenotype of DC. The current results thus identify a previously unappreciated role for Gαs-regulated cAMP synthesis and cAMP/PKA in DC in determining Th subset differentiation and resultant responses.     

Accelerated influx of dendritic cells into the lymph nodes draining skin sites exposed to attenuated cercariae of Schistosoma mansoni in guinea-pigs

We compared temporal changes in the cell composition of the skin-draining lymph nodes (SLN) in guinea-pigs exposed percutaneously to normal or attenuated cercariae of Schistosoma mansoni. Different populations were analysed by flow cytometry of double-stained cells by monoclonal antibodies to the major histocompatibility complex class II molecule and lymph node cells of guinea-pigs. Exposure to S. mansoni caused a marked increase in the proportion of B cells and dendritic cells (DC) on day 2, reaching a peak number on day 4. These changes were comparable in both infected and vaccinated animals exposed to normal or attenuated parasites, respectively. Total number of DC, however, showed different kinetics; in infected animals, the number peaked on day 2 and then gradually declined, whereas it reached a higher peak on day 4 in vaccinated animal. Daily injection of bromo-deoxyuridine after exposure to the parasite reduced the total number of DC in the SLN on day 4. A reduction in DC counts in the contralateral side SLN was also evident in vaccinated animals. Our results indicate that a significant number of newly formed DC are recruited to the skin by 4th day of vaccination, followed by increased efflux to the SLN. It is possible that retention of attenuated S. mansoni in the skin may cause accelerated recruitment of newly formed DC from the bone marrow, and facilitate transport and processing of antigens highly expressed on attenuated parasites.     

慢加急性乙型肝炎肝衰竭患者肝组织树突状细胞特点研究

目的观察慢加急性乙型肝炎肝衰竭（Acute-on-chronic hepatitis B liver failure,ACHBLF）患者外周血和肝组织树突状细胞及其亚群的分布特征。方法选择11例进行肝移植的ACHBLF、10例慢性乙型肝炎患者和5例健康人,取外周血和肝组织,使用流式细胞仪计数外周血单个核细胞（PBMCs）和肝内浸润淋巴细胞（LILs）中浆样树突细胞（plasmacytoid DC,DCs）和髓样树突细胞（myeloid DC,mDCs）的频率,应用polyI：C和CpG2216刺激培养PBMCs和LILs,采用ELISA法检测上清IFN-α、IL-12和IL-10水平;采用免疫组化技术检测肝内pDC和mDC的分布。结果 ACHBLF患者肝内pDCs与外周血pDCs频率具有显著性差异（P〈0.05）,而肝内mDC的频率与外周血之间差异无统计学意义（P〉0.05）;ACLF患者经刺激的PBMCs和LILs能够分泌IFN-α和IL-12,但LILs分泌细胞因子的水平较PBMCs明显降低,而分泌IL-10却较PBMCs明显升高;ACHBLF患者肝组织浸润了大量的pDCs和mDCs。结论 ACHBLF患者肝内浸润大量的DC亚群细胞,并优先分泌IL-10,在发病机制中可能具有局部的免疫调节作用。     

DC-SIGN在慢性乙型肝炎病毒感染时树突状细胞成熟活化中的作用

目的研究慢性HBV感染时,DC-SIGN在树突状细胞（DC）成熟和活化中介导的作用。方法将α-甘露糖苷酶抑制剂-基夫碱作用于HepG2.2.15细胞,收获上清中的高甘露糖型HBV颗粒,并于第5 d加入到外周血单核细胞衍生的DC培养基中,培养至第7 d,采用流式细胞仪检测DC表面CDla、CD83、CD80、CD86、HLA-DR分子的表达,MTT法检测DC刺激淋巴细胞增殖的能力,ELISA法检测DC分泌IL-12的水平。结果高甘露糖型HBV组,与天然的HBV组相比,DC表面CDla、CD83、CD80、CD86、HLA-DR分子的表达增加,分泌IL-12的水平升高,刺激同种异体淋巴细胞增殖的能力亦明显增强,且上述效应均可被DC-SIGN特异性抗体所阻断。结论 DC-SIGN识别高甘露糖型HBV后可以促进DC的成熟和活化,天然的HBV可能利用α-甘露糖苷酶参与的去甘露聚糖修饰来逃避DC-SIGN的识别,从而诱导DC功能的缺陷。