Hepatitis B virus e antigen (HBeAg) may have a negative effect on dendritic cell generation

Hepatitis B virus (HBV) continues to be a serious worldwide health problem despite the use of protective HBV vaccines and therapeutic regimens against chronic HBV infection. Chronic HBV patients cannot induce sufficient immune responses against the virus. HBV and its antigens are believed to suppress immune responses during chronic infection. Hence, studying the role of HBV in immune suppression is very important for the development of alternative therapeutic strategies for HBV infections.     

Hydrophobic interactions in Plasmodium falciparum invasion into human erythrocytes

Human glycophorins block in vitro invasion of Plasmodium falciparum merozoites into human erythrocytes. A segment of glycophorin A which appears to be involved in the inhibition, is at, or adjacent to, the membrane-spanning domain of the molecule. To study the role of hydrophobic interactions in the inhibition, a series of proteins were derivatized with lipophilic side groups, and tested for inhibitory activity. Glycophorin A became five times more inhibitory after derivatization with nitrobenzylfurazan groups. Bovine serum albumin was derivatized to different degrees with nitrobenzylfurazan, dinitrobenzyl, trinitrobenzyl, dansyl, disulfonic stilbene, and fluorescein groups. The presence of hydrophobic side groups on the protein rendered it highly inhibitory to invasion, whereas the presence of hydrophilic substitutes such as disulfonic stilbenes did not. Other soluble proteins such as human serum albumin, transferrin, ovalbumin, fetuin and casein derivatized with dinitrobenzyl groups, were also found to block invasion. Inhibition was not a result of toxic effects of the protein derivatives on parasite metabolism or development. A minimum of ten hydrophobic side groups per bovine serum albumin was required in order to elicit appreciable inhibition. The invasion blocking activity was highly correlated with the rate and affinity of binding of the derivatized macromolecules to heptyl-Sepharose. The latter provided a quantitative measure for the capacity of amphiphiles to undergo hydrophobic interactions with insoluble matrices. The results of the present study indicate that hydrophobic interactions may be an essential component in the invasion of P. falciparum merozoites into human erythrocytes.     

Induction, distribution and modulation of upper airway allergic inflammation in mice

BACKGROUND: To further elucidate mechanisms of human allergic rhinosinusitis, we studied the induction, distribution and modulation of allergen-induced upper airway inflammation in a BALB/c mouse model. METHODS: Allergic inflammation induced with ovalbumin (OVA) by intraperitoneal (IP) injection in alum was compared to repeated intranasal instillation. The type and distribution of inflammatory cells was compared in the respiratory and olfactory epithelial compartments. Eosinophil distribution was assessed using Scarlet Red stain and a polyclonal antibody recognizing eosinophil major basic protein (MBP). The role of interleukin (IL)-5 in upper airway inflammation was tested by administration of polyclonal anti-IL-5 antibody during the sensitization protocol. RESULTS: Unsensitized control mice receiving saline failed to develop upper airway eosinophil infiltration. IP OVA-sensitized mice developed marked upper airway mucosal eosinophil infiltration after aerosol OVA challenge, whereas repeated intranasal instillation of OVA produced qualitatively similar, but less intense eosinophil infiltration. Using either sensitization protocol, eosinophil infiltration was seen in areas of the lower portion of the nasal septum, the floor and the lower lateral walls of the mid-caudal region of the nasal cavity. Immunofluorescence staining for MBP confirmed this distribution of eosinophils but also demonstrated some eosinophils in the maxillary sinuses and in circumscribed regions of the ethmoturbinates. All areas of eosinophil infiltration were lined by respiratory epithelium. The selective infiltration of respiratory but not olfactory epithelium by eosinophils was unassociated with a measurable induction of epithelial ICAM-1 or eotaxin expression. OVA-induced upper airway eosinophil infiltration was found to be IL-5 dependent, since administration of a polyclonal anti-IL-5 antibody (TRFK-5) during OVA sensitization resulted in a marked modulation (80% decrease) in eosinophil infiltration in response to subsequent OVA challenge. CONCLUSION: The mouse upper airway, specifically in areas containing respiratory epithelium, is a target for OVA-induced allergic inflammation. This selective infiltration of respiratory, but not olfactory, epithelium is, in part, dependent upon IL-5. This model is useful for further dissection of the inflammatory response with genetic manipulations and targeted immunological approaches.     

Ovalbumin‐specific immunoglobulins A and G levels at age 2 years are associated with the occurrence of atopic disorders

Background Humoral responses to food antigens may reflect the propensity of a child's immune system to develop tolerance to innocuous antigens. Early nutrition as well as probiotics may influence these immunological responses. Objective To study the association of humoral responses to early food antigens with the administration of prebiotics and probiotics, with the occurrence of allergy, and with the length of exclusive breastfeeding. Methods In a randomized double‐blind allergy prevention trial in high‐risk children, 1018 mothers took probiotics or placebo from the 36th week of gestation, and their newborn infants received probiotics and prebiotics or placebo during 6 months. At 2 and 5 years, we evaluated the cumulative incidence of allergic diseases (food allergy, eczema, asthma, rhinitis) and sensitization (skin prick test ?3 mm or serum antigen‐specific IgE>0.7 kU/L). In 688 infants at age 2, we measured in sera‐specific IgA, IgG, IgG1, and IgG4 antibody levels to cow's milk (CM), α‐casein (CAS), β‐lactoglobulin (BLG), and ovalbumin (OVA) with ELISA, and specific IgE levels to CM and hen's egg with UniCap. Results Probiotic treatment (n=342) compared with placebo (n=346) showed no effect on serum food‐specific IgA, IgG, IgG1, or IgG4 concentrations at age 2. Atopic children had higher OVA‐IgA (P<0.001), OVA‐IgG (P=0.001), OVA‐IgG1 (P<0.001), and egg‐IgE but lower OVA‐IgG4/egg‐IgE ratio (P<0.001) than non‐atopic children. Longer duration of exclusive breastfeeding (?4 vs. <4 months) was associated with reduced CM‐ and CAS‐specific serum IgA (P<0.001) and IgG levels (P<0.001; P=0.003). Conclusion and Clinical Relevance Allergy was associated with more intense IgA and IgG responses to OVA. Breastfeeding depressed humoral responses, whereas prebiotics and probiotics supplementation showed no immunomodulatory effect. The effect of probiotics on allergies is not mediated through food‐specific antibody responses. Furthermore, OVA‐specific IgA and IgG antibodies may help in assessing the risk for atopy. [Trial registration: Clinicaltrials.gov NCT00298337] Cite this as: A. K. Kukkonen, E. M. Savilahti, T. Haahtela, E. Savilahti and M. Kuitunen, Clinical & Experimental Allergy, 2011 (41) 1414–1421.     

Supplementation with aqueous leaf extract of Morinda lucida enhances immunorestoration and upregulates the expression of cytokines and immunostimulatory markers

Morinda lucida Benth (Rubiaceae) is a versatile plant used in traditional medicine of many countries for the treatment of a variety of ailments and the claims of efficacy are particularly remarkable in the treatment of infections and immuno-inflammatory disorders. In this study, we investigated the immunostimulatory and immunorestorative properties of the aqueous leaf extract of Morinda lucida (AML) in cultures of murine splenic lymphocytes and in cyclophosphamide-induced immunosupression models, respectively. Administration of AML (100 and 250 mg/kg; per os) in alternate days significantly (P < 0.05) increased specific total IgG, IgG1, and IgG2a responses to ovalbumin by as much as 2-10 fold when compared to untreated controls. In cyclophophamide treated mice, the rate of wound healing, leukopoiesis , and body weight recovery were all enhanced by oral supplementation with AML (100 and 250 mg/kg) in a dose-dependent manner. In vitro cultures of BALB/C splenocytes treated with AML (12.5 and 50 μg/ml) for 24 h resulted in 5-10 fold increase in IFNγ and IL-4 measured by cytokine capture ELISA. Surface expression of immunostimulatory markers, CD69 and CD25, measured flow cytometrically by FACS analyis, were also significantly (P < 0.05) upregulated on splenic T and B cells by as much as 8-20 fold. Taken together, the results of these studies show the potent immunostimulatory and immunorestorative properties of the aqueous leaf extract of Morinda lucida, which may explain some of the beneficial effects of the plant in the treatment of infections and immuno-inflammatory disorders.     

Colonic bacterial superantigens evoke an inflammatory response and exaggerate disease in mice recovering from colitis

BACKGROUND & AIMS: There is renewed interest in commensal bacteria as triggers of idiopathic disease, a concept that is prominent in inflammatory bowel disease (IBD). Here the effect of intracolonic instillation of Staphylococcus aureus enterotoxin B (SEB), a model superantigen (SAgs: potent T-cell stimuli), into mice was examined. METHODS: Mice (Balb/c, severe combined immunodeficient [SCID], V beta 8(+) ovalbumin transgenic [OVA-Tg], interleukin 10 [IL-10] knockout [KO]) received a single intrarectal (IR) dose of SAg and colonic form (histology, myeloperoxidase [MPO] activity) and function (ion transport) were assessed 12-72 hours later. In subsequent studies the potential for SEB to reactivate disease in mice recovering from dextran sodium sulfate (DSS)-induced colitis (5 days at 4% [wt/vol] followed by 14 days normal water) was examined. RESULTS: SEB-treated Balb/c mice displayed a time- and dose-dependent colonic inflammation (increased MPO, histologic damage score, and macrophage number). Similar events occurred in response to other SAgs, namely S. aureus enterotoxin A (SEA) and Yersinia pseudotuberculosis mitogen. Ion transport, the driving force for water movement, was unaffected by SEB treatment. SCID mice developed no inflammation after IR SEB delivery, whereas OVA Tg mice displayed enhanced responsiveness. Although SEB treatment of IL-10 KO mice did elicit a response, the inflammation was transitory and did not hasten the spontaneous colitis seen in these mice. Finally, mice recovering from DSS-induced colitis showed a worsening of the disease when challenged with SEB; IR SEB evoked significant increases in MPO, macrophage infiltration, T-cell activation (i.e., CD25 expression), and perturbed epithelial ion transport. CONCLUSIONS: Lumen-derived bacterial SAgs can elicit a local inflammation and aggravate enteric inflammatory disorders in which they were not the causative agent.     

Nerve growth factor promotes expression of costimulatory molecules and release of cytokines in dendritic cells involved in Th2 response through LPS-induced p75NTR

Introduction: Nerve growth factor (NGF) plays an important role in asthmatic inflammatory responses. However, the effects of NGF on dendritic cells (DCs) in asthmatic inflammation remain unknown. Therefore, we examined the effects of NGF on co-stimulatory molecules and the release of cytokines after ovalbumin (OVA) and a low dose of LPS (low LPS) stimulation of dendritic cells. Methods: Bone-marrow-derived dendritic cells (BMDCs) were collected from 6- to 8-week-old wide or TLR4^?/? mice. BMDCs were treated with OVA and/or low LPS for 12h, and then stimulated with NGF for 24h. ELISA and flow cytometry were performed to measure TSLP, IL-6, IL-10, and IL-12 production and MHCII and CD86 expression on BMDCs. BMDCs were exposed to p75 neurotrophin receptor (p75NTR) inhibitor (TAT-Pep5) or NF-kB inhibitor (QNZ) 30 min prior to NGF 1 h after NGF intervention, the levels of RelA and RelB in cytoplasmic and nuclear were detected by west blot. Co-cultured BMDCs with naïve CD4⁺ T cells, and ELISA was used to detect IL-4 and INF-γ levels. Results: NGF was found to markedly promote OVA and low LPS-induced expression of MHCII, CD86, secretion of TSLP and IL-6, and Th2-response-stimulating capacity of BMDCs. NGF affected BMDCs through LPS-induced p75NTR expression. TAT-Pep5 or QNZ could attenuate the promotive effect of NGF. Conclusions: NGF facilitates OVA with lowLPS-induced maturation of mouse BMDCs through LPS-up-regulated p75 NTR via activation of NF-κB pathways, providing another mechanism for the involvement of NGF in the Th2 response.     

粉螨性小鼠哮喘模型的建立与评估

目的探讨采用椭圆食粉螨提取浸液建立C57BL/6小鼠哮喘模型的方法。方法 45只C57BL/6小鼠随机分成3组:PBS阴性对照组、卵清蛋白(OVA)阳性对照组、椭圆食粉螨(Ale o)哮喘模型组。用酶联免疫吸附试验(ELISA)检测支气管肺泡灌洗液(BALF)、脾细胞培养上清液中IL-4、IL-17和IFN-γ的含量,计数BALF中细胞总数并分类,同时切取小鼠未灌洗侧肺组织进行病理学观察。结果 OVA阳性对照组、Ale o模型组小鼠脾细胞上清和BALF中IL-4、IL-17及IFN-γ含量与PBS阴性对照组相比,差异均具有统计学意义(P<0.05或P<0.01);OVA阳性对照组、Ale o模型组小鼠BALF中细胞总数及各类细胞数与PBS阴性对照组相比,差异有统计学意义(P<0.05或P<0.01);小鼠未灌洗侧肺组织病理学观察显示,OVA阳性对照组和Ale o模型组小鼠肺组织可见大量炎症细胞浸润,以嗜酸性粒细胞、淋巴细胞及巨噬细胞为主。结论用椭圆食粉螨提取浸液建立的C57BL/6小鼠哮喘模型具有过敏性哮喘的主要特征。     

Emerging roles of basophils in allergic inflammation

Basophils have long been neglected in immunological studies because they were regarded as only minor relatives of mast cells. However, recent advances in analytical tools for basophils have clarified the non-redundant roles of basophils in allergic inflammation. Basophils play crucial roles in both IgE-dependent and -independent allergic inflammation, through their migration to the site of inflammation and secretion of various mediators, including cytokines, chemokines, and proteases. Basophils are known to produce large amounts of IL-4 in response to various stimuli. Basophil-derived IL-4 has recently been shown to play versatile roles in allergic inflammation by acting on various cell types, including macrophages, innate lymphoid cells, fibroblasts, and endothelial cells. Basophil-derived serine proteases are also crucial for the aggravation of allergic inflammation. Moreover, recent reports suggest the roles of basophils in modulating adaptive immune responses, particularly in the induction of Th2 differentiation and enhancement of humoral memory responses. In this review, we will discuss recent advances in understanding the roles of basophils in allergic inflammation.