Study of adjuvant effect of model surfactants from the groups of alkyl sulfates, alkylbenzene sulfonates, alcohol ethoxylates and soaps.

The sodium salts of representatives of anionic surfactants, dodecylbenzene sulfonate (SDBS), dodecyl sulfate (SDS) and coconut oil fatty acids, and a nonionic surfactant, dodecyl alcohol ethoxylate, were studied for adjuvant effect on the production of specific IgE antibodies in mice. The surfactants were injected subcutaneously (sc) in concentrations of 1000, 100, 10 or 1 mg/l, respectively, together with 1 microg of ovalbumin (OVA). In addition, groups of mice received OVA in saline (control group) or in Al(OH)(3) (positive adjuvant control group). After the primary immunization the mice were boosted up to three times with OVA (0.1 microg sc) in saline. OVA-specific IgE antibodies were determined by the heterologous mouse rat passive cutaneous anaphylaxis test. The results were confirmed by a specific ELISA method. After the first booster, the Al(OH)(3) group and the 10 mg/l SDS group showed a statistically significant increase in OVA specific IgE levels. After two boosters, a statistically significant suppression in OVA-specific IgE production occurred with SDS (1000 mg/l), SDBS (1000 and 100 mg/l), coconut soap (1000 mg/l) and the alcohol ethoxylate (10 mg/l). This study suggests that a limited number of surfactants possess an adjuvant effect whereas all surfactants at certain levels can suppress specific IgE production.     

Adjuvant effects of inhaled mono-2-ethylhexyl phthalate in BALB/cJ mice

Phthalates, including di(2-ethylhexyl) phthalate (DEHP), are widely used and have been linked with the development of wheezing and asthma. The main metabolite of DEHP, mono-2-ethylhexyl phthalate (MEHP), was investigated for adjuvant effects in a mouse inhalation model. BALB/cJ mice were exposed to aerosols of 0.03 or 0.4 mg/m(3) MEHP 5 days/week for 2 weeks and thereafter weekly for 12 weeks together with a low dose of ovalbumin (OVA) as a model allergen. Mice exposed to OVA alone or OVA+Al(OH)(3) served as negative and positive controls, respectively. Finally, all groups were exposed to a nebulized 1% OVA solution on 3 consecutive days to investigate the development of an inflammatory response. Serum, bronchoalveolar lavage (BAL) fluid, and draining lymph nodes were collected 24h later. In the OVA+Al(OH)(3) group, significantly increased levels of OVA-specific IgE and IgG1 in serum as well as of eosinophils in BAL fluid were observed. OVA-specific IgG1 production in both MEHP groups was significantly increased. OVA-specific IgE and IgG2a were not increased significantly. A dose-dependent increase in inflammatory cells was observed in BAL fluid, leading to significantly higher lymphocyte and eosinophil numbers in the OVA+0.4 mg/m(3) MEHP group. Ex vivo cytokine secretion by cultures of draining lymph nodes suggested a T(H)2 profile of MEHP. In conclusion, MEHP acted as a T(H)2 adjuvant after inhalation. However, it is suggested that the inflammation in the MEHP groups was primarily mediated by an IgG1-dependent mechanism. To address implications for humans, a margin-of-exposure was estimated based on the lack of significant effects on IgE production and inflammation after exposures to 0.03 mg/m(3) MEHP observed in the present study and estimated human exposure levels.     

Airway inflammation and adjuvant effect after repeated airborne exposures to di-(2-ethylhexyl)phthalate and ovalbumin in BALB/c mice

BACKGROUND: Epidemiological studies have suggested an association between exposure to phthalate plasticizers, including di-(2-ethylhexyl)phthalate (DEHP), and increased prevalence of asthma, rhinitis or wheezing. Furthermore, studies in mice have demonstrated an adjuvant effect from DEHP after parenteral administration with the model allergen ovalbumin (OVA). OBJECTIVE: Exposures to DEHP were investigated for adjuvant effects and airway inflammation in a mouse inhalation model. METHODS: BALB/cJ mice were exposed to aerosols of 0.022-13 mg/m(3) DEHP and 0.14 mg/m(3) OVA 5 days/week for 2 weeks and thereafter weekly for 12 weeks. Mice exposed to OVA alone or OVA+Al(OH)(3) served as control groups. Finally, all groups were exposed to a nebulized 1% OVA solution on three consecutive days. Serum, bronchoalveolar lavage (BAL) fluid, and draining lymph nodes were collected 24h later. RESULTS: In the OVA+Al(OH)(3) group, significantly increased levels of OVA-specific IgE and IgG1 in serum as well as of eosinophils in BAL fluid were observed. DEHP affected OVA-specific IgG1 production in a concentration-dependent manner, whereas little effect was seen on IgE and IgG2a. Dose-dependent increases in inflammatory cells were observed in BAL fluids, leading to significantly higher lymphocyte, neutrophil and eosinophil numbers in the OVA+13 mg/m(3) DEHP group. Ex vivo cytokine secretion by cultures of draining lymph nodes suggested that DEHP has a mixed Th1/Th2 cytokine profile. CONCLUSION: Airborne DEHP is able to increase serum IgG1 and lung inflammatory cell levels, but only at very high concentrations. Realistic DEHP levels do not have an adjuvant effect or induce allergic lung inflammation in the present mouse model.     

Does lipophilicity per se induce adjuvant effects? Methyl palmitate as model substance does not affect ovalbumin sensitization

Anthopogenically introduced substances and pollutants are suspected to promote sensitization and development of allergic airway diseases, that is, acting as adjuvants. Lipophilicity may serve as an immunological warning signal, promoting adjuvant effects. Whether the lipophilicity of an inhaled compound induces immunomodulatory effects was investigated in a murine inhalation model with the highly lipophilic methyl palmitate (MP) as model substance. First, studies of acute effects following a 1-h exposure of up to 348 mg/m3 MP showed no effects on cell composition in bronchoalveolar lavage (BAL) or on lung function parameters. Thus, MP did not possess irritant or inflammatory properties, which may be a precursive stimulus for adjuvant effects. Second, mice were exposed to aerosols of MP, 6 or 323 mg/m3, for 1 h followed by a 20-min low-dose ovalbumin (OVA) inhalation. OVA only and OVA + Al(OH)3 served as control groups. Exposures were performed 5 times/wk for 2 wk followed by a weekly exposure for 10 wk. Finally, the mice were challenged with a high-dose OVA aerosol for 3 consecutive days. Neither OVA-specific immunoglobulin (Ig) G1, IgE, or IgG2a production, nor inflammatory cells in BAL, nor respiratory patterns were significantly affected in the MP groups. The OVA + Al(OH)3 group had a significantly higher IgG1 and IgE production, as well as higher eosinophil infiltration in the BAL fluid. These studies showed that effects of adjuvants not are necessarily due to their lipophilicity; that is, additional structural properties are required.     

Nano Titanium Dioxide Particles Promote Allergic Sensitization and Lung Inflammation in Mice

Abstract: The purpose of this study was to investigate whether photocatalytic TiO₂ nanoparticles have adjuvant effect, when administered in combination with ovalbumin (OVA) in mice. Mice were immunized via intraperitoneal injections of OVA, OVA + TiO₂ or OVA + Al(OH)₃ and challenged with aerosols of OVA. At the end of the study, serum was analysed for content of OVA‐specific IgE, IgG1 and IgG2a antibodies, and the bronchoalveolar lavage fluid (BALF) was analysed for content of inflammatory cells and levels of interleukin (IL)‐4, IL‐5, IL‐10 and interferon‐γ. The TiO₂ particles promoted a Th2 dominant immune response with high levels of OVA‐specific IgE and IgG1 in serum and influx of eosinophils, neutrophils and lymphocytes in BALF. The TiO₂ particles induced a significantly higher level of OVA‐specific IgE than the standard adjuvant Al(OH)₃. However, the two substances were comparable regarding the level of eosinophilic inflammation and interleukins present in BALF.     

Immunomodulatory effects of gyokuheifusan on INF-gamma/IL-4 (Th1/Th2) balance in ovalbumin (OVA)-induced asthma model mice

Asthma, a common, chronic lung disease in industrialized countries, is characterized by the production of large quantities of IgE antibody by B cells and a decrease of the IFN-gamma/IL-4 (Th1/Th2) ratio. Gyokuheifusan (GHS) is a classical formulation of traditional Chinese medicine (TCM) that is usually prescribed to prevent or treat respiratory tract diseases, such as respiratory infection and bronchial asthma. In order to evaluate the possible effectiveness of GHS on bronchial asthma, its immunomodulatory activity was examined in ovalbumin (OVA)-induced asthma model mice. All mice, except those in the normal group, were sensitized by intraperitoneal (IP) administration of OVA emulsified with Al(OH)(3), and a second immunization was given 6 d later. After a further 13, 17 and 21d, mice were challenged with inhalation of aerosolized OVA solution, except for the normal group, which received mock sensitization using saline-Al(OH)(3) emulsion and were challenged with an aerosol of saline without OVA. Allergen-specific IgE and total IgE in plasma were both significantly increased in the disease-control group. These increases were markedly blocked by GHS treatment. IFN-gamma released by splenocytes was significantly increased after co-culture with OVA for 24 h, 48 h, and 72 h. GHS treatment further elevated the IFN-gamma content compared with the disease-control group. The production of IL-4 was significantly increased when splenocytes were simulated with OVA for 72 h, but this increase was blocked by GHS treatment, so that GHS returned the decreased IFN-gamma/IL-4 (Th1/Th2) ratio of the disease-control group to the normal range. These results indicate that GHS may inhibit the development and severity of asthma.     

Enhanced desensitization efficacy by liposomal conjugation of a specific antigen

Since liposomes are known as strong adjuvants, we attempted to use liposomes in immunotherapy as adjuvants, and to achieve desensitization in pre-sensitized mice. At first, we sensitized mice with intraperitoneal injection of model antigen, 100 microg ovalbumin (OVA), with Alum and treated them with liposome composed of distearoylphosphatidylcholine (DSPC) and cholesterol (2:1 as a molar ratio), which was coupled with a small amount of OVA (10 microg OVA in 400 nmol DSPC and 200 nmol cholesterol-liposome was injected into 20 g mouse). It is well known that antigen-specific immunotherapy increases IgG blocking antibodies and decreases in IgE antibodies. The treatment with i.v. injection of OVA-liposome at days 8, 10, and 12 after sensitization strongly suppressed OVA-specific IgE production without affecting IgG level after the boost (100 microg OVA with Alum). Moreover, the treatment with high-density OVA-liposome (10 microg OVA in 80 nmol DSPC and 40 nmol cholesterol-liposome/20 g mouse) not only strongly suppressed IgE levels but also reduced IgG production after the boost of OVA-sensitized mice suggesting the importance of liposomal characteristic in desensitization immunotherapy. Next we reduced the dose of OVA-liposome and the desensitization effect was also observed at the dose of as low as 1 microg OVA on OVA-liposome/mouse. On the contrary, free OVA did not affect the production of both IgG and IgE levels. Biodistribution study indicated that OVA-liposome was highly accumulated in spleen of OVA-sensitized mice compared to control liposome at 3 h after i.v. injection. These results suggest that the liposomal OVA effectively interacts with and desensitizes immune cells, therefore, liposomes coupling with a certain antigen may be effective in allergy immunotherapy.     

4-Carvomenthenol ameliorates the murine combined allergic rhinitis and asthma syndrome by inhibiting IL-13 and mucus production via p38MAPK/NF-κB signaling pathway axis

The aim of this study was to analyze the 4-carvomenthenol (carvo) oral treatment on the experimental model of the combined allergic rhinitis and asthma syndrome (CARAS). BALB/c mice were OVA-sensitized on day zero and 7th (50 μg/mL OVA in 10 mg/mL Al (OH)3) and OVA-challenged (5 mg/mL, 20 μL/animal) for three weeks. In the last week, the animals were dally challenged with aerosol of OVA and the carvo treatment (12.5, 25 or 50 mg/kg) occurred one hour before each OVA-challenge. Data were analyzed and p < 0.05 was considered significant. Carvo (12.5–50 mg/kg) decreased significantly the eosinophil migration into the nasal (NALF) and bronchoalveolar (BALF) cavities as well as on the nasal and lung tissues of sick animals. The treatment also decreased mucus production on both tissue sections stained with PAS (periodic acid-Schiff satin). In addition, the histological analyzes demonstrated that sick mice presented hyperplasia and hypertrophy of the lung smooth muscle layer followed by increasing of extracellular matrix and carvo (50 mg/kg) inhibited these asthmatic parameters. We analyzed the allergic rhinitis signals as nasal frictions and sneezing and observed that carvo decreased these two signals as well as serum OVA-specific IgE titer, type 2 cytokine synthesis, mainly IL-13, with increasing of IL-10 production. Decreasing of IL-13 production corroborated with decreasing of mucus production and these effects were dependent on p38MAPK/NF-κB(p65) signaling pathway inhibition. Therefore, these data demonstrated that a monoterpene of essential oils presents anti-allergic property on an experimental model of CARAS suggesting a new drug prototype to treat this allergic syndrome.     

Fine particles of widely different composition have an adjuvant effect on the production of allergen-specific antibodies

Diesel exhaust particles (DEP) are reported to increase the specific IgE response to allergens, and results from our laboratory suggest that the particle core of DEP contribute to this adjuvant activity. The purpose of the present study was to explore further the adjuvant effect of particles per se, that is particles by themselves. NIH/Ola mice were given two intraperitoneal injections with ovalbumin (OVA; 10 microg) alone or OVA in combination with PSP, polytetrafluoroethylene (teflon), titanium dioxide (TiO(2)) or amorphous silica particles (2.8x10(10)-2.8x10(12)). Blood samples were drawn 7 days after the last injection, and serum levels of allergen-specific and total IgE and IgG2a were measured. All types of particles gave increased levels of allergen-specific IgE and IgG2a. Similar results were obtained after intranasal or intratracheal instillation with OVA plus PSP or silica. Our results indicate that fine particles of widely different composition may have an adjuvant effect on the production of allergen-specific antibodies.     

Nitrogen dioxide: no influence on allergic sensitization in an intranasal mouse model with ovalbumin and diesel exhaust particles

The role of traffic-related air pollution in the development of allergic diseases is still unclear. We therefore investigated if NO?, an important constituent of traffic-related air pollution, promotes allergic sensitization to the allergen ovalbumin (OVA). We also examined if NO? influenced the allergy adjuvant activity of diesel exhaust particles (DEP). For this purpose, mice were exposed intranasally to OVA with or without DEP present, immediately followed by exposure to NO? (5 or 25 parts per million [ppm]) or room air for 4?h in whole body exposure chambers. Eighteen hours after the last of three exposures, the lungs of half of the animals were lavaged with saline and markers of lung damage and lung inflammation in the bronchoalveolar lavage fluid (BALF) were measured. Three weeks later, after intranasal booster immunizations with OVA, the levels of OVA-specific IgE and IgG2a antibodies in serum were determined. Both NO? (25 ppm) and DEP gave lung damage, measured as increased total protein concentration in BALF, whereas only NO? seemed to stimulate release of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In contrast, only DEP significantly increased the number of neutrophils. Furthermore, DEP in combination with OVA stimulated the production of serum allergen-specific IgE antibodies. NO?, however, neither increased the production of allergen-specific IgE antibodies, nor influenced the IgE adjuvant activity of DEP. Thus, based on our findings, NO? seems to be of less importance than combustion particles in the development of allergic diseases after exposure to traffic-related air pollution.     

Aqueous extract of peanut skin and its main constituent procyanidin A1 suppress serum IgE and IgG1 levels in mice-immunized with ovalbumin

In this study, we investigated the effects of an aqueous extract of peanut (Arachis hypogaea L.) seed skin (PSE) and its main constituent procyanidin A1 (PA) on the allergic response to allergen ovalbumin (OVA) in a mouse model. Mice immunized interaperitoneally with OVA dramatically increased anti-OVA IgE and total IgG1 levels in serum compared with non-treated control mice. Oral injection of PSE at doses ranging from 10 to 100 mg/kg/d (for 21 consecutive days) decreased anti-OVA IgE and IgG1 levels 21 d after OVA-immunization. OVA-induced increments in spleen weight and peripheral white blood cell count were also suppressed by this PSE administration. Polyphenol-enriched fractions from apple (30 mg/kg) and grape seed (30 mg/kg) also decreased anti-OVA IgE level but did not affect total IgG1 levels. Oral injection of PA (1 to 10 mg/kg/d) purified from PSE resulted in a suppression of IgE and total IgG1 levels in serum. An increment of serum interleukin-4 level in mice that were immunized with OVA was reduced by all tested samples, whereas PSE and PA were the only compounds that could reverse the reduced interferon-gamma level by OVA. These findings suggest that intake of PSE or its main active constituent PA may prevent an allergic reaction by inhibiting immunoglobulin synthesis, and the mechanism of this action of PSE and PA is in part due to their regulation of T helper cytokine production.     

A BALB/c mouse model for assessing the potential allergenicity of proteins: Comparison of allergen dose,sensitization frequency,timepoint and sex

The present study was to investigate the possibility of using the BALB/c mouse as an animal model for assessing the potential allergenicity of proteins.Specific IgE and IgG1 against ovalbumin were induced by dosing BALB/c mice via intraperitoneal injection (absence of adjuvant). The effects of various allergen doses (5 mg, 0.5 mg or 0.05 mg OVA), sensitization times (twice or five times), timepoints (day 14 or day 28) and sex (male or female) were studied. IL-4, IFN-γ, OVA-specific IgE and IgG1 were measured by enzyme-linked immunosorbent assay (ELISA).A general finding was that mice treated with 0.05 mg OVA had the highest OVA-specific IgE and IgG1, statistically significant higher specific IgE and IgG1 were observed in groups sensitized five times than twice, OVA-specific IgE and IgG1 on day 28 were statistically higher than day 14, and higher IL-4 was observed in OVA-allergic mice than control mice.These results demonstrate that the BALB/c mouse model treated with 0.05 mg OVA intraperitoneally on days 0, 3, 6, 9, 12 might be used for further experiments. OVA-specific IgE and IgG1 should be detected on day 28. Further studies including reproducibility and other conditions were required before using the BALB/c mouse model for assessing the potential allergenicity of proteins.     

Exposure of brown Norway rats to diesel exhaust particles prior to ovalbumin (OVA) sensitization elicits IgE adjuvant activity but attenuates OVA-induced airway inflammation.

Exposure to diesel exhaust particles (DEP) during the sensitization process has been shown to increase antigen-specific IgE production and aggravate allergic airway inflammation in human and animal models. In this study, we evaluated the effect of short-term DEP exposure on ovalbumin (OVA)-mediated responses using a post-sensitization model. Brown Norway rats were first exposed to filtered air or DEP (20.6 +/- 2.7 mg/m3) for 4 h/day for five consecutive days. One day after the final air or DEP exposure (day 1), rats were sensitized with aerosolized OVA (40.5 +/- 6.3 mg/m3), and then again on days 8 and 15, challenged with OVA on day 29, and sacrificed on days 9 or 30, 24 h after the second OVA exposure or the final OVA challenge, respectively. Control animals received aerosolized saline instead of OVA. DEP were shown to elicit an adjuvant effect on the production of antigen-specific IgE and IgG on day 30. At both time points, no significant airway inflammatory responses and lung injury were found for DEP exposure alone. However, the OVA-induced inflammatory cell infiltration, acellular lactate dehydrogenase activity and albumin content in bronchoalveolar lavage (BAL) fluid, and numbers of T cells and their CD4+ and CD8+ subsets in lung-draining lymph nodes were markedly reduced by DEP on day 30 compared with the air-plus-OVA exposure group. The OVA-induced nitric oxide (NO) in the BAL fluid and production of NO, interleukin (IL)-10, and IL-12 by alveolar macrophages (AM) were also significantly lowered by DEP on day 30 as well as day 9. DEP or OVA alone decreased intracellular glutathione (GSH) in AM and lymphocytes on days 9 and 30. The combined DEP and OVA exposure resulted in further depletion of GSH in both cell types. These results show that short-term DEP exposure prior to sensitization had a delayed effect on enhancement of the sensitization in terms of allergen-specific IgE and IgG production, but caused an attenuation of the allergen-induced airway inflammatory responses.     

Adjuvant effect of quaternary ammonium compounds in a murine model

It has been suggested that occupational exposure to quaternary ammonium compounds (QACs) may promote the development of allergic airway diseases. In this study, hazard identifications of the adjuvant effect of cetylpyridinium chloride (CPC), dimethyldioctadecylammonium bromide (DDA), hexadecyltrimethylammonium bromide (HTA), and tetraethylammonium chloride (TEA) were performed in a screening bioassay. Female BALB/c mice were injected subcutaneously with the model allergen ovalbumin (OVA) alone or together with different quantities of one of the QAC test compounds. After one or two boosters, levels of OVA-specific IgE, IgG1 and IgG2a antibodies were measured in sera. CPC and DDA increased IgE and IgG1 antibody production, respectively, compared to the OVA control group, whereas HTA and TEA showed no adjuvant effect. Nevertheless, when TEA was given in combination with DDA, the adjuvant effect was up to six-fold higher than the adjuvant effect of DDA alone. Only DDA had a statistically significant adjuvant effect on IgG2a antibody levels.     

Nitrogen dioxide: no influence on allergic sensitization in an intranasal mouse model with ovalbumin and diesel exhaust particles

The role of traffic-related air pollution in the development of allergic diseases is still unclear. We therefore investigated if NO₂, an important constituent of traffic-related air pollution, promotes allergic sensitization to the allergen ovalbumin (OVA). We also examined if NO₂ influenced the allergy adjuvant activity of diesel exhaust particles (DEP). For this purpose, mice were exposed intranasally to OVA with or without DEP present, immediately followed by exposure to NO₂ (5 or 25 parts per million [ppm]) or room air for 4?h in whole body exposure chambers. Eighteen hours after the last of three exposures, the lungs of half of the animals were lavaged with saline and markers of lung damage and lung inflammation in the bronchoalveolar lavage fluid (BALF) were measured. Three weeks later, after intranasal booster immunizations with OVA, the levels of OVA-specific IgE and IgG2a antibodies in serum were determined. Both NO₂ (25?ppm) and DEP gave lung damage, measured as increased total protein concentration in BALF, whereas only NO₂ seemed to stimulate release of the proinflammatory cytokine tumor necrosis factor alpha (TNF-α). In contrast, only DEP significantly increased the number of neutrophils. Furthermore, DEP in combination with OVA stimulated the production of serum allergen-specific IgE antibodies. NO₂, however, neither increased the production of allergen-specific IgE antibodies, nor influenced the IgE adjuvant activity of DEP. Thus, based on our findings, NO₂ seems to be of less importance than combustion particles in the development of allergic diseases after exposure to traffic-related air pollution.     

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.     

Effects of asian sand dust, Arizona sand dust, amorphous silica and aluminum oxide on allergic inflammation in the murine lung

The aggravating effects of Asian sand dust (SD) and related minerals on the allergic inflammation were examined in the murine lungs. The toxic materials adsorbed onto Asian SD, Arizona SD were inactivated by heat-treatment. ICR mice were administered mineral samples (0.1 mg/mouse) and/or ovalbumin (OVA) (1 microg/mouse) - normal saline (control), Asian SD, Arizona SD, SiO2, Al2O3, OVA, OVA + Asian SD, OVA + Arizona SD, OVA + SiO2, and OVA + Al2O3 - intratracheally four times at two-week intervals. All samples tested enhanced eosinophil recruitment induced by ovalbumin in the submucosa of the airway, which has a goblet cell proliferation in the bronchial epithelium. Arizona SD alone caused a slight increase of neutrophils in bronchoalveolar lavage fluids along with pro-inflammatory mediators, such as keratinocyte chemoattractant, but Asian SD alone or Al2O3 alone showed no effect. The test particles, except Al2O3, synergistically increased the numbers of eosinophils in BALF induced by ovalbumin. In particular, Arizona SD and SiO2 synergistically increased the eosinophil relevant cytokine and chemokine, such as IL-5 and monocyte chemotactic protein (MCP)-3. The aggravating effects of the samples were dependent on the SiO2 content. All samples tested also induced the adjuvant effects to specific IgG1 production by OVA. These results suggest that the aggravated allergic inflammation by mineral dusts may be due to the mineral elements (mainly SiO2). The enhancement by Arizona SD may be mediated, at least partially, by the increased expression of IL-5 and MCP-3 and also by the modulated expression of IL-5 and MCP-3.     

The adjuvant effect of di-(2-ethylhexyl) phthalate is mediated through a PPARalpha-independent mechanism

Previous studies in BALB/c mice revealed an adjuvant effect of di-(2-ethylhexyl) phthalate (DEHP) to simultaneously administered ovalbumin. DEHP is the most commonly used phthalate plasticizer. In vivo formed metabolites of DEHP are peroxisome-proliferator-activated receptor (PPAR) ligands, a group of chemicals that may have immunomodulatory properties. To study whether the PPARalpha receptor was involved in the adjuvant effect of DEHP, PPARalpha-deficient 129/Sv mice were exposed intraperitoneally to a mixture of OVA and DEHP, and the OVA-specific IgE, IgG1 and IgG2a responses were compared to the corresponding responses in the wild-type strain. The study showed that the adjuvant mechanism of DEHP is mediated through a PPARalpha-independent mechanism. Compared to mice only given OVA, DEHP induced highly increased levels of OVA-specific IgG1 and IgG2a, both in the wild-type and in the PPARalpha knock-out strains, indicating that DEHP is a mixed Th1/Th2 adjuvant.     

Nivalenol inhibits total and antigen-specific IgE production in mice

Nivalenol (NIV) has been reported to induce hyperproduction of IgA, which is regulated by T-helper 2 cells (Th2); however, whether IgE production, which is under the regulation of Th2 cells, is induced by this compound remains largely unknown. We examined the effect of NIV on antigen-specific IgE production using ovalbumin (OVA)-specific T cell receptor alphabeta-transgenic mice. The mice produced significant amounts of total and antigen-specific IgE, IgG1, and IgA in serum when given OVA orally. Administration of NIV with OVA suppressed total IgE and OVA-specific IgE, IgG1, and IgA production significantly. Cytokine assay using splenocytes obtained from mice given the OVA plus NIV diet revealed that interleukin 4 (IL-4) production was suppressed and interleuin-2 (IL-2) production was enhanced. These results suggest that the inhibition of IL-4 production and enhancement of IL-2 production induced by NIV suppressed total and antigen-specific IgE production.     

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; i.p.) 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.