Inhibitory effects of cryptoporus polysaccharide on airway constriction, eosinophil release, and chemotaxis in guinea pigs

AIM: To study effects of cryptoporus polysaccharide (CP) on antigen-induced bronchoconstriction, eosinophil peroxidase (EPO) release in vivo, and on platelet activating factor (PAF)-induced eosinophil chemotaxis in vitro in guinea pig. METHODS: The asthma model of guinea pig was formed with ovalbumin (OVA). The changes of lung resistance (RL) and dynamic lung compliance (Cdyn), EPO level in bronchoalveolar lavage fluids (BALF) and eosino- phil migration were determined. RESUL…     

Artificial Tears Inhibit the Development of Experimental Immune-mediated Blepharoconjunctivitis

Purpose To investigate whether treatment with artificial tears inhibits the development of experimental immune-mediated blepharoconjunctivitis (EC).Methods Brown Norway rats were immunized with ovalbumin (OVA) or ragweed (RW) emulsified in complete Freunds adjuvant. Fourteen days after immunization, the rats were challenged with the same antigen (Ag) in eye drops. Treated rats were administered artificial tears by eye drops immediately after, 15min after, or 30min after the Ag challenge. Treatment doses of 2, 4, or 8 drops per eye were evaluated. Twenty-four hours after the Ag challenge, the rats were killed and their eyes were harvested for histological studies.Results Treatment with artificial tears immediately after and 15min after challenge with partially insoluble RW Ag suppressed infiltration of inflammatory cells into the conjunctiva. Inhibition was not observed at any time following challenge with OVA Ag, which is a soluble protein. The treatment dose of artificial tears administered did not affect the extent of inhibition of EC following challenge with either Ag.Conclusions Treatment with artificial tears by eye drops inhibited the development of EC induced by the partially insoluble RW Ag when administered within 15min of the Ag challenge. Jpn J Ophthalmol 2004;48:530–534 © Japanese Ophthalmological Society 2004     

Oral-Antigen Delivery via a Water-in-Oil Emulsion System Modulates the Balance of the Th1/Th2 Type Response in Oral Tolerance

Purpose. To evaluate the ability of a water-in-oil (W/O) emulsion containing ovalbumin (OVA), a model antigen, to induce oral tolerance and to elucidate the mechanism for the induction of oral tolerance by the emulsion system. Methods. A W/O emulsion containing OVA was prepared and evaluated its ability to induce oral tolerance in mice. Also, the Th1/Th2 balance in the mice tolerized was investigated in terms of the ratios of anti-OVA IgG2a titer to anti-OVA IgG1 titer (IgG2a/IgG1 ratios) and cytokine profiles. Results. Anti-OVA total IgG antibody titer of mice administered OVA in saline was approximately 3.5-fold higher than that of the mice administered OVA in W/O emulsion at a dose of 0.1 mg/mouse/day. Similar total IgG responses were observed between the above two at a dose of 1 mg/mouse/day. The IgG2a/IgG1 ratios decreased as the dose of OVA in W/O emulsion, but not in saline, increased at doses of 0, 0.1, and 1 mg/mouse/day. Interferon- secretion of PLN cells from the mice administered OVA in W/O emulsion decreased, whereas their interleukin-4 secretion remained high. Although interferon- secretion for the mice administered OVA in saline decreased, interleukin-4 secretion did not change. Conclusions. The present study suggests that oral delivery of OVA via the W/O emulsion system may more efficiently enhance the induction of Th2-dominated imbalance than that of OVA in saline.     

Peptidoleukotriene (PLT) Release and Absorption from the Airways of the Isolated Perfused Guinea Pig Lung Following Chemical and Antigenic Challenge

Purpose. To study the release and absorption of peptidoleukotrienes (PLTs) from the airways of the guinea pig lung following calcium ionophore A23187 (CI), benzalkonium chloride (BAC), ethylene diamine tetra-acetic acid (EDTA) or ovalbumin (OA) challenge. Methods. PLT C4/D4/E4 were quantified in the perfusate of the isolated perfused guinea pig lung (IPGPL) following intratracheal administration of CI, BAC, EDTA or OA in different doses. The formation and airway-to-perfusate transfer kinetics of PLTs were analyzed by fitting mean data for cumulative PLT in perfusate vs. time to an A B C first-order release and transfer model, with dose-dependent transfer rate constants. Results. CI induced apparent first order release of PLTs with a t 1.2 minutes. The amount of PLT released was CI dose-dependent, as was the airway-to-perfusate transfer rate constant. These reached maxima of 0.254 g and 0.0557 min.^–1, respectively, around a CI dose of 100 g. In OA-sensitized IPGPL preparations, OA induced a similar dose-dependent release of PLTs, although the rates of PLT release were much greater and more variable than those seen with CI. In OA sensitized IPGPL preparations, at an OA dose of 1000 g, the maximum amount of PLT released was 0.289 g and the maximal airway-to-perfusate transfer rate constant was 0.0229 min^–1. BAC and EDTA failed to induce quantifiable PLT release from the airways. Conclusions. Rapid release of the inflammatory mediators, PLT C4/ D4/E4, could be induced in the unsensitized IPGPL by CI, and in the sensitized IPGPL by OA. Transfer into perfusate occurred in both cases with dose-dependent t ranging from 12.4 through 57.8 minutes.     

建立支气管哮喘大鼠模型的新方法及评价

目的 探讨建立支气管哮喘动物模型的新方法.方法 20只清洁级SD大鼠随机分为哮喘组和对照组,每组10只,哮喘组以小剂量卵蛋白(OVA)1 mg致敏并激发为大鼠哮喘模型,对照组以氢氧化铝凝胶致敏,以0.9％氯化钠溶液激发.观察2组大鼠肺组织病理、支气管肺泡灌洗液(BALF)细胞分类及血清OVA-specific IgE水...     

OVA-bound nanoparticles induce OVA-specific IgG1, IgG2a,and IgG2b responses with low IgE synthesis

There is an urgent requirement for a novel vaccine that can stimulate immune responses without unwanted toxicity, including IgE elevation. We examined whether antigen ovalbumin (OVA) conjugated to the surface of nanoparticles (NPs) (OVA-NPs) with average diameter of 110 nm would serve as an immune adjuvant. When BALB/c mice were immunized with OVA-NPs, they developed sufficient levels of OVA-specific IgG1 antibody responses with low levels of IgE synthesis, representing helper T (Th)2-mediated humoral immunity. OVA-specific IgG2a and IgG2b responses (i.e., Th1-mediated immunity) were also induced by secondary immunization with OVA-NPs. As expected, immunization with OVA in alum (OVA-alum) stimulated humoral immune responses, including IgG1 and IgE antibodies, with only low levels of IgG2a/IgG2b antibodies. CD4-positive T cells from mice primed with OVA-NPs produced substantial levels of IL-21 and IL-4, comparable to those from OVA-alum group. The irradiated mice receiving OVA-NPs-primed B cells together with OVA-alum-primed T cells exhibited enhanced anti-OVA IgG2b responses relative to OVA-alum-primed B cells and T cells following stimulation with OVA-NPs. Moreover, when OVA-NPs-primed, but not OVA-alum-primed, B cells were cultured in the presence of anti-CD40 monoclonal antibody, IL-4, and IL-21, or LPS plus TGF-β in vitro, OVA-specific IgG1 or IgG2b antibody responses were elicited, suggesting that immunization with OVA-NPs modulates B cells to generate IgG1 and IgG2b responses. Thus, OVA-NPs might exert their adjuvant action on B cells, and they represent a promising potential vaccine for generating both IgG1 and IgG2a/IgG2b antibody responses with low IgE synthesis.     

A soluble thymic stromal lymphopoietin (TSLP) antagonist, TSLPR-immunoglobulin, reduces the severity of allergic disease by regulating pulmonary dendritic cells

Recent studies show that thymic stromal lymphopoietin (TSLP) plays a critical role in the upstream phase of the allergic cascade to induce T helper type 2 cell (Th2)-dominant allergic diseases. However, the effect of blocking TSLP signalling with the soluble TSLP receptor (TSLPR), TSLPR-immunoglobulin (Ig), on asthma development needs further investigation. Here, we examined the effects of TSLPR-Ig on asthmatic airway inflammation and dendritic cell (DC) function. TSLPR-Ig (comprising the extracellular domain of murine TSLPR and an IgG2a Fc tail) purified from transfected COS-7 cells reduced the expression of CD40, CD80 and CD86 on TSLP-activated DCs in vitro. We also investigated the mechanisms underlying TSLPR-Ig-mediated amelioration of allergic airway inflammation in a murine asthma model. When TSLP signalling was blocked by intratracheal administration of TSLPR-Ig prior to sensitization, allergen-specific serum IgE levels, airway tissue inflammation, inflammatory cell infiltration and Th2 cytokine levels in the bronchiolar lavage fluid (BALF) were reduced significantly. This was because of the TSLP-Ig-mediated down-regulation of co-stimulatory molecule expression on pulmonary DCs. We also transferred bone marrow-derived mature DCs (mDCs) into the airways of asthmatic mice. Intratracheal administration of TSLPR-Ig prior to the transfer of mDCs reduced eosinophilic airway inflammation and Th2 differentiation significantly. Collectively, these data suggest that local use of TSLPR-Ig prevents airway inflammation, at least in part, by regulating DC function, and that blocking TSLP signalling using TSLPR-Ig may be a novel strategy for the treatment of asthma bronchiale.     

Human milk polyunsaturated long‐chain fatty acids and secretory immunoglobulin A antibodies and early childhood allergy

The possible protective effect of breast milk against atopic manifestations in infancy, i.e. atopic eczema and food allergy, has been controversial for the last decades. Besides the methodological problems, differences in the composition of human milk could explain these controversies. The aim of this study was to investigate the composition of polyunsaturated fatty acids (PUFA) and secretory immunoglobulin A (S‐IgA) levels to food proteins (ovalbumin and β‐lactoglobulin) and an inhalant allergen (cat) in milk from mothers of allergic and non‐allergic children. Blood samples were obtained at birth and at 3 months from 120 children. Skin prick tests were performed at 6, 12 and 18 months, and the development of atopic diseases was assessed in the children. Breast milk samples were collected from their mothers at birth and monthly during the lactation period. Milk PUFA composition was measured by gas chromatography, and enzyme‐linked immunosorbent assay (ELISA) was used to measure total S‐IgA, anti‐cat S‐IgA, anti‐ovalbumin S‐IgA, and anti‐β‐lactoglobulin S‐IgA. Allergic disease developed in 44/120 children (22/63 children of allergic mothers and 22/57 children of non‐allergic mothers). Lower levels of eicosapentaenoic acid, C20:5 n‐3 (EPA), docosapentaenoic acid C22:5n‐3 (DPA), and docosatetraenoic acid C22:4 n‐6 (DHA) (p < 0.05 for all) were found in mature milk from mothers of allergic as compared to milk from mothers of non‐allergic children. The total n‐6 : total n‐3 and the arachidonic acid, C20:4 n‐6 (AA) : EPA ratios were significantly lower in transitional and mature milk from mothers of allergic children, as compared to milk from mothers of non‐allergic children. The PUFA levels in serum of allergic and non‐allergic children were largely similar, except for higher levels of C22:4 n‐6 and C22:5 n‐6 (p < 0.05 for both) and a higher AA : EPA ratio in serum phospholipids in the former group (p < 0.05). Changes in the levels of milk PUFA were reflected in changes in PUFA serum phospholipids, particularly for the n‐6 PUFA. The AA : EPA ratio in maternal milk was related, however, to the AA : EPA only in serum from non‐allergic children, while this was not the case in allergic children. The levels of total S‐IgA, anti‐cat S‐IgA, anti‐ovalbumin S‐IgA, and anti‐β‐lactoglobulin S‐IgA in milk from mothers of allergic, as compared to non‐allergic, children were similar through the first 3 months of lactation. Low levels of n‐3 PUFA in human milk, and particularly a high AA : EPA ratio in maternal milk and serum phospholipids in the infants, were related to the development of symptoms of allergic disease at 18 months of age. The milk PUFA composition influenced the composition of PUFA in serum phospholipids of the children. We also showed that the lower levels of colostral anti‐ovalbumin S‐IgA and lower total S‐IgA in mature milk from atopic mothers did not influence the development of allergic disease in the children up to 18 months of age. The findings indicate that low α‐linolenic acid, C18:3 n‐3 (LNA) and n‐3 long‐chain polyunsaturated fatty acids (LCP) 20–22 carbon chains, but not the levels of S‐IgA antibodies to allergens, are related to the development of atopy in children.     

Effect of maternal egg consumption on breast milk ovalbumin concentration

Background Maternal dietary avoidance of egg has been recommended to treat egg allergy in breastfed infants. However, only one of three randomized controlled trials have produced evidence in favour of this recommendation.
Objective Our objective was to assess human milk ovalbumin (OVA) concentration after daily maternal ingestion of one cooked egg for 3 weeks.
Methods Mothers with egg-sensitive, eczematous breastfed infants were randomly allocated to consume one muffin per day containing one egg (egg group, n =16) or a similar egg-free muffin (control group, n =16) for 21 days (Days 3–23). All mothers and infants followed an egg-free diet. Breast milk samples were collected at two hourly intervals for 6 h after eating the test muffins on Days 3, 12 and 23 and breast milk OVA concentration measured. Infant eczema was assessed at the commencement and completion of the trial.
Results Women in the egg group had higher OVA concentrations in breast milk than the control group at all time-points. Within each dietary group, OVA excretion did not change with time. OVA was not detected in breast milk of 25% of women in the egg group. In contrast, infant eczema symptom scores significantly reduced with time for both groups.
Conclusion Human milk OVA is related to maternal dietary egg intake, but a significant proportion of women either have a delayed excretion or may not excrete OVA in their breast milk.