Homologous Passive Cutaneous Anaphylaxis Research Articles

Effects of Medium Molecular Weight Heparinyl Phenylalanine on Type I Hypersensitivity.

We investigated the inhibitory action of medium molecular weight heparinyl phenylalanine (MHF) on type I hypersensitivity in comparison with medium molecular weight heparinyl arginine (MHR). MHF and MHR were synthesized from heparin (HE) to decrease the side-effect of HE based on its anticoagulant action and used in this study. MHF demonstrated a significant inhibitory action on 48-h homologous passive cutaneous anaphylaxis in rats. Although MHF did not affect the death of mice injected with a lethal dose of histamine, it significantly prolonged the survival time of mice administered a lethal dose of compound 48/80. On the other hand, MHR did not inhibit type I hypersensitivity. The inhibitory action of MHF on the type I allergic reaction was due to a reduction or delay in histamine release from mast cells. MHF may be a potent anti-allergic agent.

Biocompatibility of cross-linked hyaluronate (Gel-200) for the treatment of knee osteoarthritis

To compare the biocompatibility and immunogenicity of two intra-articular hyaluronan formulations, Gel-200 (Gel-One(®)) and hylan G-F 20 (Synvisc(®) series). A comparison of the biocompatibility of Gel-200 and hylan G-F 20 was made using a rat subcutaneous air pouch model and the knee joint of normal rabbits. Immunogenicity was evaluated using a homologous passive cutaneous anaphylaxis (PCA) assay in guinea pigs. In the air pouch model in rats, characteristic fibrous belts formed in the subcutaneous tissue. Injection of hylan G-F 20 into the air pouch induced granulomatous nodules primarily composed of macrophages, multinucleated giant cells, and eosinophils accompanied with the test material in the center of the nodules in the fibrous belt. Furthermore, the thickness of the fibrous belt in the hylan G-F 20 group increased significantly compared to the saline group. Injection of Gel-200 into the air pouch induced neither granulomatous inflammation nor significant thickening of fibrous belt, while foamy macrophages containing the test material were observed. Intra-articular injection of hylan G-F 20 into the rabbit knee joints induced granulomatous inflammation, eosinophil infiltration, and significant increase in the number of cells in the synovial fluid, while these findings were absent in the Gel-200 group. In the immunogenicity assay, hylan G-F 20 induced a positive PCA reaction, but the Gel-200 did not. Gel-200 showed more favorable biocompatibility and less immunogenicity compared to hylan G-F 20. Gel-200 is expected to be a single injection hyaluronan product with less safety concerns for the treatment of knee osteoarthritis (OA) pain.

Anti-Allergic and Antioxidant Activity of 5-Hydroxy-3,6,7,3’,4’- Pentamethoxy Flavone Isolated from Leaves of Vitex negundo

Objectives: Bioactivity guided fractionation of leaves of Vitex negundo for their anti-allergic and antioxidant activity and structure elucidation of active fraction responsible for these activities. Methods: Ethyl acetate fraction of leaves of Vitex negundo was fractionated into aqueous sub fraction, acetone sub fraction and chloroform sub fraction according to possible separation of chemical spots present in ethyl acetate fraction using thin layer chromatography and developed solvent system. Anti-allergic activity of aqueous sub fraction, acetone sub fraction and chloroform sub fraction was carried out using homologous passive cutaneous anaphylaxis model in rat. Antioxidant activity of aqueous sub fraction, acetone sub fraction and chloroform sub fraction was carried out using egg albumin induced oxidative stress in guinea pigs. Various spectroscopy methods like Ultraviolet-visible (UV) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, Electron impact (EI)-Mass spectroscopy and Proton nuclear magnetic resonance (H1 NMR) spectroscopy were used to determine structure of active sub fraction of leaves of Vitex negundo that possesses anti-allergic and antioxidant activity. Results: Aqueous sub fraction produced significant lesser amount of dye leakage at 200 mg/kg (1.6648±0.0372; p<0.001), when compared with the control group (4.0094±0.2474; p<0.001). Animals treated with aqueous sub fraction showed significantly higher superoxide dismutase (SOD) activity, catalase activity and reduced glutathione level and lower malondialdehyde (MDA) level as compared to untreated sensitized animals. Structure of aqueous sub fraction was determined as a 5-hydroxy- 3,6,7,3’,4’-pentamethoxy flavone. Conclusion: Aqueous sub fraction of leaves of Vitex negundo possesses anti-allergic and antioxidant activity. It is identified as a 5-hydroxy-3,6,7,3’,4’-pentamethoxy flavone. It may be useful in the treatment of various allergic and immunologic diseases and to prevent oxidative stress in many diseases like cancer, liver injury, cardiovascular disease, asthma etc. Keywords: Allergy, Antioxidant, Vitex negundo, 5-hydroxy-3, 6, 7, 3’, 4’-pentamethoxy flavone, Spectroscopy methods, Electron impact, Fourier-transform infrared, Glutathione, Proton nuclear magnetic resonance, Hydrogen peroxide.

Various Screening Methods for Anti-allergic Activity: An Overview

Development of compounds having diverse antiallergic activities to be used in the treatment of various conditions like rhinitis, dermatitis, asthma, food allergies and pollenosis, requires screening methods with efficient reproducibility and perfection. In such process some series of steps were followed; Antiasthmatic and relative activities were performed on albino guinea pig and isolated trachea through sensitization of animals with well known antigens such as egg albumin and Bordetella pertusis vaccine. Bronchodilator activities for both compound and standard (aminophyline) against contraction were produced by standard agonists like acetylcholine, histamine and egg albumin. Bronchoprotective activities were performed against various mediators. Experiments on sensitized isolated ileum, mast cell stabilizing activities on rat mesenteries, homologous passive cutaneous anaphylaxis (PCA) using above mentioned antigens were followed. Histamine release measurement using human basophilic cell line, KU812 suspension, biological assays using goat antimouse Immunoglobulin E (GAME) and biotinylated GAME, murine and human recombinant Interleukin 4(IL4) antimouse and antihuman CD40 antibodies for ex vivo Immunoglobulin E (IgE) assay, IgE response in human cells and finally in vivo IgE response, Ig ELISA and cytokine assay were performed. Thus after successful completion of such studies it might be possible to establish a versatile antiallergic compound. Some of these studies are discussed here.

Inter‐laboratory comparisons of assessment of the allergenic potential of proteins in mice

Assessment of the potential allergenicity of novel proteins, including those expressed in genetically modified plants, is an important issue. In previous studies, we have shown that the IgE measurement induced by systemic exposure of BALB/c mice to a range of proteins correlates broadly with what is known of their allergenic potential in humans. The approach used a homologous passive cutaneous anaphylaxis (PCA) assay that reflects IgE-dependent biological activity and is of sufficient sensitivity to detect IgE production in the absence of adjuvant. In previous studies, the immunization phase was conducted independently in two separate facilities, and the subsequent analytical work (PCA) conducted in a single facility. The purpose here was to further evaluate the transferability of this approach. To this end, BALB/c mice were exposed to a range of doses of peanut agglutinin or ovalbumin, allergenic proteins of peanut and hen's egg, respectively, in two independent laboratories. Serial doubling dilutions of serum pooled for each treatment group were analyzed for specific IgE. At higher doses of allergen very similar, or identical, IgE titers were achieved in both laboratories, although at lower doses, responses were somewhat more variable. These data demonstrate that, although technically demanding, the measurement of protein allergen-induced IgE antibody production in mice using PCA is relatively robust and is transferable and reproducible between laboratories. This approach may provide a useful tool for the safety assessment of novel proteins and suggests that continued evaluation of the approach with a wider range of protein allergens and non-sensitising proteins is justified.

Influence of plant lipids on immune responses in mice to the major Brazil nut allergen Ber e 1

Lipids, particularly bacterial lipopolysaccharide, can impact on immune responses to proteins, with low doses enhancing type 2 responses. We have examined the influence of natural plant lipid extracts on antibody responses provoked in mice by recombinant Ber e 1, the major allergen in Brazil nuts. BALB/c strain mice were immunized (by intraperitoneal injection) with natural or recombinant Ber e l produced in Pichia pastoris and admixed with various lipid fractions isolated from Brazil nuts. Serum samples were analysed for specific IgE antibody by homologous passive cutaneous anaphylaxis assay and for IgG by enzyme-linked immunosorbant assay. Exposure to recombinant (lipid-free) Ber e 1 alone failed to induce detectable IgG or IgE antibody. Co-administration of the total lipid fraction (with reduced triglyceride levels), sterol-rich, or polar lipid fractions, resulted in marked adjuvant effects on IgG and IgE. However, the beta-sitosterol and glycolipid-rich fractions were associated with only low-level IgG antibody, and had little impact on IgE antibody production. Natural Ber e 1 containing endogenous lipids also provoked IgG and IgE antibody responses. Identical IgE and IgG antibody responses were detected regardless of whether natural or recombinant Ber e 1 was used as substrates for analyses. Endogenous Brazil nut lipids are required for the induction of optimal antibody responses to Ber e 1 in the BALB/c strain mouse. Appropriate antibody binding sites are present on both natural and recombinant forms of Ber e 1, suggesting that the impact of lipid is at the induction phase, rather than antibody recognition, and is possibly required for efficient antigen presentation.

Development of a Novel Mouse Anaphylaxis Model Produced by Intermittent Intravenous Injections of Ovalbumin without Adjuvant

This study was performed to develop mouse anaphylaxis model using ovalbumin (OA) as an antigen, with no adjuvant, and an intravenous route of administration. OA at dose levels from 0.5 to 500 mg/kg was injected 3 times into the tail vein of female CD-1 (ICR) mice at 4-day intervals. Clinical signs and extravasation of Evans blue dye (vascular permeability) were observed, serum histamine levels and airway resistance were measured, and histopathological examinations were performed. Furthermore, to detect serum IgE and IgG, heterologous and homologous passive cutaneous anaphylaxis tests were performed. Additionally, strain differences in susceptibility to OA anaphylaxis was examined with 3 mouse strains: ICR, BALB/c and C57BL/6 mice. Shortly after the 3rd injection, most of the animals exhibited systemic anaphylactic signs including death, and this was accompanied by increases in vascular permeability, plasma histamine levels, and airway resistance. Four days after the 2nd injection, anti-OA IgE and IgG were detected in sera of mice injected with 0.5 and 5.0 mg/kg or higher doses of OA, respectively. Histological findings included: congestion in many tissues; detachment of mucosal epithelial cells in the gastrointestinal tract; enhanced death, decreased numbers of lymphocytes, and increased numbers of macrophages in the lymphoid tissues. ICR mice were shown to be most susceptible to the OA anaphylaxis of the 3 mouse strains examined. In conclusion, the results demonstrate that 3 intermittent intravenous injections of OA without adjuvant at 4-day intervals can induce anaphylactic shock in mice, in particular, most effectively in ICR mice, and that the anaphylaxis is characterized by specific IgE and IgG production.

A mouse model for food allergy using intraperitoneal sensitization

Food allergy is an important health issue. With the increasing interest in novel foods derived from transgenic crop plants, there is a growing need for the development of approaches for the characterization of the allergenic potential of proteins. Although most foreign proteins are immunogenic (able to induce IgG antibody responses), relatively few are important food allergens with the capacity to provoke IgE antibody production. There is currently no validated animal model for the determination of allergenic potential of food proteins. One approach that appears to show some promise is outlined in the current chapter. BALB/c strain mice are immunized by intraperitoneal injection and the potential to cause allergenicity assessed as a function of the induction of specific IgE antibody, measured by homologous passive cutaneous anaphylaxis. Progress to date with this method is summarized, and comparisons are made with other experimental models, including considerations of route of exposure, use of adjuvants and selection of appropriate end points.

Readministration of IgE Is Required for Repeated Passive Cutaneous Anaphylaxis in Mice

Background: Homologous passive cutaneous anaphylaxis (PCA) is an established technique that provides a useful tool to study local inflammation due to mast cell activation. Since mast cells are responsive to repeated challenge by IgE receptor crosslinking in vitro, we investigated the responsiveness of mice to repeated PCA activation. Methods: Female BALB/c mice were sensitized with intradermal injection of IgE into the ear and provocated through intravenous injection of trinitrophenol-BSA. Repeated provocation was administered, and the outcome was determined by colorimetrical measurement of Evans blue dye leakage. Results: After local IgE injection, mice could be challenged to demonstrate a PCA reaction at least up to 13 days after IgE sensitization. In contrast, passively sensitized mice did not respond to repeated antigen challenge, i.e. a second provocation administered between 1 and 12 days after the first PCA reaction. However, if these mice were intradermally resensitized with IgE at the same site after the first challenge, they became responsive to the repeated challenge. Conclusions: Mast cells become desensitized upon PCA reaction, and resensitization with IgE is critical for mice repeatedly stimulated by PCA activation.

Inhibitory Effects of Selaginella tamariscina on Immediate Allergic Reactions

The anti-allergic effects of a 70% ethanol extract from Selaginella tamariscina herb (EST) were evaluated in this study. EST given at the doses of 500 and 1000 mg/kg can inhibit mouse systemic anaphylactic shock induced by compound 48/80 in a dose-dependent manner. It can also dose-dependently block rat homologous passive cutaneous anaphylaxis and skin reactions caused by exogenous histamine and serotonin with a significant difference observed at the dose of 1000 mg/kg. In addition, EST can reduce histamine release from rat peritoneal mast cells triggered by compound 48/80 and an antigen in vitro. When incubated with rat mast cells, the extract (200 microg/ml) can significantly elevate the intracellular cAMP levels. The finding suggests that EST inhibits mast cell-dependent, immediate allergic reactions. Its effects appear to be mediated by reducing the release of vasoactive amines such as histamine from mast cells via stabilizing the cell membrane and weakening the inflammatory action of these amines. Based on these results, Selaginella tamariscina and one of its active components flavonoids may be useful as potential remedies for allergic rhinitis and other allergy-related diseases.

Evaluation of an in vitro method for the measurement of specific IgE antibody responses: the rat basophilic leukemia (RBL) cell assay

The evaluation of allergenic potential is a key parameter in the safety assessment of novel proteins, including those expressed in genetically modified crops and foodstuffs. The majority of allergic reactions to food proteins are immediate type hypersensitivity reactions in which the principal biological effector is IgE antibody; the accurate measurement of specific IgE antibody is therefore a critical factor in experimental systems designed to characterize protein allergenic potential. Due to the presence of much higher concentrations of other immunoglobulin isotypes, the assessment of specific serum IgE antibody poses substantial technical challenges. We have examined the utility of the rat basophilic leukemia (RBL) cell line for the measurement of murine IgE responses. RBL cells were sensitized with mouse monoclonal anti-dinitrophenyl (DNP) IgE antibody and challenged with DNP-albumin conjugates with various hapten substitution ratios (SR). Polyclonal anti-OVA IgE antisera were also assessed for activity in the RBL assay. Results were compared with titers measured in homologous passive cutaneous anaphylaxis (PCA) assay. Marked degranulation of RBL cells was induced by conjugates with SRs of between 16 and 32, whereas conjugates with lower SRs (of 10 or 3) failed to elicit significant serotonin release. All conjugates were able to induce mast cell degranulation in vivo in a PCA assay. Anti-OVA antisera with PCA titers of 1/32 to 1/64 failed to stimulate RBL cell degranulation, whereas high titer antibody (1/2048 to 1/4096 by PCA) induced a positive RBL cell response. Successful stimulation of RBL cell degranulation requires not only appropriate epitope densities but also high affinity antibody. These data indicate that this assay is inappropriate for the routine analysis of specific polyclonal IgE antibody responses such as those that are induced by exposure to complex protein allergens.

Evaluation of protein allergenic potential in mice: dose-response analyses.

With the increasing interest in novel foods derived from transgenic crop plants, there is a growing need for the development of approaches for the characterization of the allergenic potential of proteins. Whereas immunogenicity is a common property of foreign proteins, including food proteins, relatively few are significant dietary allergens with the inherent capacity to provoke IgE antibody production and immediate-type hypersensitivity responses. In order to evaluate an approach for the measurement of the allergenic potential of proteins, detailed dose-response analyses of humoral immune responses induced following systemic exposure of BALB/c strain mice to proteins known to differ in terms of sensitizing activity have been conducted. Mice were exposed to a range of concentrations of ovalbumin, a major allergenic constituent of hen's egg, a purified peanut allergen, Arachis hypogea agglutinin, or to the milk allergen bovine serum albumin, and to materials considered to lack significant allergenicity: a crude potato protein extract and a purified potato protein, potato agglutinin. The specific IgE antibody was measured by homologous passive cutaneous anaphylaxis assay, and the specific IgG antibody was measured by enzyme-linked immunosorbent assay. Each of the five proteins was immunogenic in mice, inducing IgG antibody responses at all doses tested, although there was some variation with respect to the vigour of IgG responses. Marked differences in the capacity of these proteins to induce IgE responses were observed, however, with relatively high-titre IgE antibody provoked by all three allergens over the dose ranges examined, whereas the potato proteins stimulated low-titre IgE antibody at the highest dose (10%) only. Importantly, differences in IgE antibody production have been observed against a background of equivalent immunogenicity (IgG antibody responses). The data presented here suggest that the measurement of antibody (IgE) responses in BALB/c mice appears to identify allergens accurately and to distinguish them from those materials that apparently lack allergenicity.

Induction of IgE antibody responses by protein allergens: inter-laboratory comparisons

There is a growing interest in the development of methods for the evaluation of the allergenic potential of novel proteins. One approach is the measurement of specific IgE antibody production stimulated by systemic (intraperitoneal; ip) exposure of BALB/c strain mice. In the current investigations, inter-laboratory comparisons have been performed of IgE antibody production induced in mice by food proteins of differing sensitizing potential. Female BALB/c strain mice ( n=5) were exposed to 0.1% peanut agglutinin, an allergenic constituent of peanuts, to 2% ovalbumin (OVA), a major allergenic constituent of hens' egg, or to a protein considered to lack significant allergenicity, potato agglutinin (5%). Specific IgE antibody was measured by homologous passive cutaneous anaphylaxis assay and IgG and IgG1 antibody production was analysed by enzyme-linked immunosorbent assay (ELISA). Two independent experiments were conducted in each laboratory, but with all serological analyses conducted in one of the laboratories. Each of the proteins induced vigorous IgG and IgG1 antibody responses, with no statistically significant differences in titres recorded between laboratories. Furthermore, OVA and potato agglutinin induced responses of equivalent immunogenicity with respect to both IgG and IgG1 antibody titres. Administration of peanut agglutinin and OVA each stimulated marked IgE antibody responses in every experiment. In the two laboratories, titres ranged from 1:32 and 1:64 for peanut agglutinin, and from 1:8 and 1:32 for OVA. In contrast, exposure to potato agglutinin failed to induce vigorous IgE production, with no detectable IgE (negative with neat serum), or titres of 1 (positive with neat serum only) recorded. These data demonstrate that the induction of IgE antibody by food proteins of differing allergenic potential is a relatively robust phenomenon and transferable between laboratories. Furthermore, these results provide additional evidence that the measurement of antibody (IgE) responses in BALB/c mice may allow discrimination between allergens and those materials that apparently lack allergenicity.

Identification and Characterization of Major Allergens in Excretory/Secretory Products of the Worm Paragonimus ohirai

Allergens present in the excretory/secretory (ES) products of adult Paragonimus ohirai were biochemically identified. Immunoblot analysis using sera from P. ohirai-infected rats revealed only two allergens to be major proteins in the ES products, with apparent molecular masses (M_r) of 27 and 29 kD. As the ES products contained a high proportion of acidic and neutral cysteine proteinases, we examined whether or not the allergens and the cysteine proteinases were identical. The acidic and neutral cysteine proteinases were biochemically purified from the ES products and showed M_r of 27 and 29 kD, respectively. The two cysteine proteinases had almost identical N-terminal amino acid sequences and were reactive with specific IgE in sera from the infected rats. The allergenicity of the cysteine proteinases was confirmed by 48-hour homologous passive cutaneous anaphylaxis. Immunoblot and immunocapture assays using anti-human IgE monoclonal antibody showed that the proteinase allergens were reactive with specific IgE of patients with paragonimiasis westermani. Also, the cysteine proteinases were reactive with specific IgG of both the infected rats and the patients. Therefore the acidic and neutral cysteine proteinases prepared from the ES products of P. ohirai will be useful allergens and antigens for the immunodiagnosis of paragonimiasis.

Protein Allergenicity in Mice

Food allergy is an important and common health issue, and there is therefore a need to identify and characterize the sensitizing potential of novel food proteins. Approaches currently used include consideration of structural similarity to, or amino acid sequence homology with, known human allergens; immunologic (generally serologic) cross-reactivity with known allergens; and the measurement of resistance to proteolytic digestion in a simulated gastric fluid. Although these methods provide information that contributes to safety assessment, they do not provide a direct evaluation of the ability of a novel protein to cause allergic sensitization. For this reason considerable interest exists in the design and evaluation of suitable animal models that may provide a more holistic assessment of allergenic potential. The experimental strategy we have adopted is to measure allergenic activity as a function of the ability of proteins to provoke IgG and IgE antibody responses in BALB/c strain mice, a strain that is known to favor immune responses of the quality required for allergic sensitization. To date, emphasis has focused on the characterization of humoral immune responses induced following systemic exposure of mice (by intraperitoneal administration) to the test material. Under these conditions it has been found that proteins known to be associated with food allergy in humans (including peanut proteins and ovalbumin) elicit both specific IgG and IgE antibody responses, measured using enzyme-linked immunosorbant and homologous passive cutaneous anaphylaxis assays, respectively. In contrast, other proteins derived from foods believed to exhibit little or no allergenic potential (such as those derived from the potato), although immunogenic in BALB/c mice (measured as a function of IgG antibody production), either failed to induce IgE antibody responses at all or were associated with only low-grade IgE production at relatively high test concentrations. In comparative analyses, exposure of BALB/c mice to proteins by gavage was found to be less sensitive and discriminatory with respect to the induction of IgE. Experience to date indicates that the inherent sensitizing potential of novel food proteins can be evaluated on the basis of antibody responses stimulated by parenteral exposure of BALB/c strain mice.

Immunogenic properties of rapidly digested food proteins following gavage exposure of mice: a comparison of ovalbumin with a potato acid phosphatase preparation

The ability of food proteins to resist digestion in simulated gastric fluid (SGF) correlates with allergenic potential. The purpose of the current investigations was to determine whether this association is due solely to the failure of unstable proteins to elicit an immune response when administered orally. We have examined immune responses induced in BALB/c mice by gavage administration of ovalbumin (OVA) and a crude potato protein extract (PPE) containing acid phosphatase activity. The stability of OVA and PPE in SGF was measured using sodium dodecyl sulfate (SDS)–polyacrylamide gel electrophoresis. The ability of these proteins to stimulate specific IgG and IgE antibody production in mice following parenteral (intraperitoneal; ip) or oral (gavage) exposure was compared using enzyme-linked immunosorbent and homologous passive cutaneous anaphylaxis assays, respectively. Both OVA and PPE induced specific IgG antibody responses when administered either by gavage or by ip injection. Parenteral, but not gavage, exposure to OVA was associated with robust IgE antibody responses. Administration of PPE failed to stimulate strong IgE production via either route of exposure. Differential stability in SGF was observed, with PPE being digested extremely rapidly (within 1 min), whereas OVA was more resistant. The strong association reported by others between stability in SGF and allergenic potential is unlikely to be solely due to orally-ingested labile proteins failing to provoke immune responses due to degradation in the stomach.

Antiallergic and anti-inflammatory properties of the ethanolic extract from Gleditsia sinensis.

This study was carried out to determine the effects of the 70% ethanolic extract from the anomalous fruits of Gleditsia sinensis LAM. (AFGS) on experimental allergic reactions and inflammation. AFGS (200, 500, 1000 mg/kg, p.o.) dose-dependently inhibited the systemic anaphylactic shock induced by compound 48/80 in mice and cutaneous reactions induced by histamine or serotonin in rats. At doses of 500 and 1000 mg/kg, AFGS showed a clear inhibition on homologous passive cutaneous anaphylaxis in rats. In vitro, AFGS significantly reduced histamine release from rat peritoneal mast cells triggered by compound 48/80 at concentrations of 20 and 50 micro/ml. Moreover, AFGS (500, 1000 mg/kg, p.o.) showed a significant inhibition on the hind paw edema in rats and ear swelling in mice caused by carrageenin and croton oil, respectively. It also clearly inhibited the vascular permeability induced by acetic acid in mice at a dose of 1000 mg/kg. These findings demonstrate that the ethanolic extract from the anomalous fruits of Gleditsia sinensis possesses antiallergic and anti-inflammatory activities, which may be mediated by reducing the release of mediators such as histamine from mast cells and weakening the inflammatory action of these mediators.

Anti-allergic effects of cnidii monnieri fructus (dried fruits of Cnidium monnieri) and its major component, osthol.

Anti-allergic effects (types I and IV) of the 70% ethanol extract (CM-ext) obtained from Cnidii Monnieri Fructus (dried fruits of Cnidium monnieri) were investigated on 48 h homologous passive cutaneous anaphylaxis (PCA), 2, 4-dinitrofluorobenzene (DNFB)-induced contact dermatitis and picryl chloride (PC)-induced contact dermatitis in experimental animals. CM-ext showed inhibitory effects on these allergic models. Osthol isolated from CM-ext also had the inhibitory effects. These results suggested that Cnidii Monnieri Fructus might be useful as an agent for allergic diseases and that its anti-allergic effect was partially attributable to a coumarin derivative, osthol.

抗アレルギー剤の開発におけるLead Evolution; 第二リード化合物としてのDimethyl(2-Phenoxyethyl) sulfonium &lt;I&gt;p&lt;/I&gt;-Toluenesulfonate

Derivatives of 2-hydroxyethyldimethylsulfonium p-toluenesulfonate (1) were evaluated for anti-allergic activity in order to develop the drug for treatment of type I allergic diseases. The IgE-induced rat homologous passive cutaneous anaphylaxis (PCA) was inhibited by some 2-alkoxy and 2-aryloxyethyl sulfonium p-toluenesulfonates. There were some correlations between hydrophobicity or electronic properties (HOMO or charge at the O atom) and anti-allergic activity or acute toxicity. Dimethyl(2-phenoxyethyl)sulfonium p-toluenesulfonate (5) was selected as a second lead compound in the next stage.

Recombinant Dirofilaria immitis-Derived Antigen Can Suppress Passive Cutaneous Anaphylaxis Reactions

Background: High levels of antigen-nonspecific IgE are produced in animals infected with helminth parasites. Generally, the increase in IgE is thought to exacerbate allergic reactions. However, high levels of antigen-nonspecific IgE may alter some features of anaphylactic reactions. To investigate the molecular mechanisms of antigen-nonspecific IgE production induced during filarial infections, we previously constructed rDiAg (recombinant Dirofilaria immitis-derived antigen) in Escherichia coli. In the present study, we examined the effect of rDiAg on the production of antigen-nonspecific IgE and on allergic cutaneous reactions in rats. Methods: Osmotic pumps filled with 200 µg of rDiAg or with 200 µl of PBS (control) were subcutaneously implanted in Wistar rats, and plasma samples were collected weekly thereafter. IgE levels were determined by ELISA. Homologous passive cutaneous anaphylaxis (PCA) reactions with anti-DNP-As IgE were examined 21 days after implantation. ¹²⁵I-IgE binding assays were examined on peritoneal mast cells from rDiAg-infused rats and control rats. Results: Antigen-nonspecific IgE production was induced in rDiAg-infused rats. PCA reactions were suppressed in rDiAg-infused rats in spite of high levels of IgE and a markedly increased expression of FcΕRI. ¹²⁵I-IgE did not bind to mast cells derived from rDiAg-infused rats, but it bound dose dependently to mast cells derived from control rats. Conclusion: The present data support the hypothesis that antigen-nonspecific IgE might protect against antigen-specific IgE by means of competition for mast cell receptors. rDiAg is an essential factor to induce antigen-nonspecific IgE in helminth infections.