Neutrophils releasing IL-17A into NETs are essential to plasma cell differentiation in inflamed tissue dependent on IL-1R.

Interleukin (IL) 17A in chronic inflammation is also produced by innate immune cells as neutrophils. Mice with chronic humoral response induced by venom of Thalassophryne nattereri (VTn) proved to be a good tool for evaluating the impact of IL-17A on the development of long-lived plasma cells in the inflamed peritoneal cavity. Here, we report that VTn induces IL-17A production by neutrophils accumulating in the peritoneal cavity and triggers the extrusion of IL-17A along with neutrophil extracellular traps (NETs). Neutrophil depletion reduced the number of IL17A-producing cells in VTn-immunized mice and blocked the differentiation of long-lived plasma cells. Specific antibody production and survival of long-lived plasma cells was ablated in VTn-immunized mice deficient in CD4, while CD28 signaling had the opposite effect on differentiation of long-lived plasma cells. Further, maturation of long-lived plasma cells in inflamed peritoneal cavity was IL-1R1 and COX-2 dependent. Finally, when both the Raf-MEK-ERK pathway and the IL-17A or IL-1R1 activities were blocked, neutrophils were unable to promote the differentiation of memory B cells into long-lived plasma cells, confirming the essential role of neutrophils and IL-17A along with NETs in an IL-1/IL-1R-dependent manner as the novel helping partner for plasma cell differentiation in chronically inflamed tissues.

Sensitization by subcutaneous route is superior to intraperitoneal route in induction of asthma by house dust mite in a murine mode / Sensibilização por via subcutânea é superior à intraperitoneal na indução de asma por ácaro em modelo murino

ABSTRACT Objective To develop a new experimental model of chronic allergic pulmonary disease induced by house dust mite, with marked production of specific immunoglobulin E (IgE), eosinophilic inflammatory infiltrate in the airways and remodeling, comparing two different routes of sensitization. Methods The protocol lasted 30 days. BALB/c mice were divided into six groups and were sensitized subcutaneously or intraperitoneally with saline (negative control), Dermatophagoides pteronyssinus (Der p) 50 or 500mcg in three injections. Subsequently they underwent intranasal challenge with Der p or saline for 7 days and were sacrificed 24 hours after the last challenge. We evaluated the titration of specific IgE anti-Der p, eosinophilic density in peribronchovascular space and airway remodeling. Results Both animals sensitized intraperitoneally and subcutaneously produced specific IgE anti-Der p. Peribronchovascular eosinophilia increased only in mice receiving lower doses of Der p. However, only the group sensitized with Der p 50mcg through subcutaneously route showed significant airway remodeling. Conclusion In this murine model of asthma, both pathways of sensitization led to the production of specific IgE and eosinophilia in the airways. However, only the subcutaneously route was able to induce remodeling. Furthermore, lower doses of Der p used in sensitization were better than higher ones, suggesting immune tolerance. Further studies are required to evaluate the efficacy of this model in the development of bronchial hyperresponsiveness, but it can already be replicated in experiments to create new therapeutic drugs or immunotherapeutic strategies.

RESUMO Objetivo Desenvolver um novo modelo experimental de doença pulmonar alérgica crônica por ácaro, com proeminente produção de imunoglobulina E (IgE) específica, infiltrado inflamatório eosinofílico nas vias aéreas e remodelamento, comparando duas vias diferentes de sensibilização. Métodos O protocolo teve duração de 30 dias. Camundongos BALB/c foram divididos em seis grupos submetidos à sensibilização por via subcutânea ou intraperitoneal com solução salina (controles negativos),Dermatophagoides pteronyssinus (Der p) 50 ou 500mcg, em três aplicações. Posteriormente, foram submetidos à provocação intranasal com Der p ou salina por 7 dias e sacrificados 24 horas após o último desafio. Avaliamos a titulação de IgE específica anti-Der p, densidade eosinofílica no espaço peribroncovascular e remodelamento das vias aéreas. Resultados Tanto os animais sensibilizados por via subcutânea como intraperitoneal produziram IgE específica anti-Der p. Ocorreu aumento da eosinofilia peribroncovascular apenas nos animais que receberam menor dose de Der p. Porém apenas o grupo sensibilizado com Der p 50mcg subcutânea apresentou remodelamento significativo das vias aéreas. Conclusão Neste modelo murino de asma, as duas vias de sensibilização levaram à produção de IgE específica e eosinofilia nas vias aéreas. No entanto, apenas a via subcutânea foi capaz de induzir ao remodelamento. Além disso, doses menores de Der p utilizadas foram superiores às mais elevadas, sugerindo tolerância. Mais estudos são necessários para avaliar a eficácia deste modelo no desenvolvimento da hiperresponsividade brônquica, mas ele pode ser replicado em experimentos para criação de novas estratégias terapêuticas medicamentosas ou imunoterápicas.

Sensitization by subcutaneous route is superior to intraperitoneal route in induction of asthma by house dust mite in a murine mode.

OBJECTIVE: To develop a new experimental model of chronic allergic pulmonary disease induced by house dust mite, with marked production of specific immunoglobulin E (IgE), eosinophilic inflammatory infiltrate in the airways and remodeling, comparing two different routes of sensitization. METHODS: The protocol lasted 30 days. BALB/c mice were divided into six groups and were sensitized subcutaneously or intraperitoneally with saline (negative control), Dermatophagoides pteronyssinus (Der p) 50 or 500 mcg in three injections. Subsequently they underwent intranasal challenge with Der p or saline for 7 days and were sacrificed 24 hours after the last challenge. We evaluated the titration of specific IgE anti-Der p, eosinophilic density in peribronchovascular space and airway remodeling. RESULTS: Both animals sensitized intraperitoneally and subcutaneously produced specific IgE anti-Der p. Peribronchovascular eosinophilia increased only in mice receiving lower doses of Der p. However, only the group sensitized with Der p 50 mcg through subcutaneously route showed significant airway remodeling. CONCLUSION: In this murine model of asthma, both pathways of sensitization led to the production of specific IgE and eosinophilia in the airways. However, only the subcutaneously route was able to induce remodeling. Furthermore, lower doses of Der p used in sensitization were better than higher ones, suggesting immune tolerance. Further studies are required to evaluate the efficacy of this model in the development of bronchial hyperresponsiveness, but it can already be replicated in experiments to create new therapeutic drugs or immunotherapeutic strategies.

Single early prenatal lipopolysaccharide exposure prevents subsequent airway inflammation response in an experimental model of asthma.

AIMS: There has been emerging interest in the prenatal determinants of respiratory disease. In utero factors have been reported to play a role in airway development, inflammation, and remodeling. Specifically, prenatal exposure to endotoxins might regulate tolerance to allergens later in life. The present study investigated whether prenatal lipopolysaccharide (LPS) administration alters subsequent offspring allergen-induced inflammatory response in adult rats. MAIN METHODS: Pregnant Wistar rats were treated with LPS (100 µg/kg, i.p.) on gestation day 9.5 and their ovariectomized female offspring were sensitized and challenged with OVA later in adulthood. The bronchoalveolar lavage (BAL) fluid, peripheral blood, bone marrow leukocytes and passive cutaneous anaphylaxis were evaluated in these 75-day-old pups. KEY FINDINGS: OVA sensitized pups of NaCl treated rats showed an increase of leucocytes in BAL after OVA challenge. This increase was attenuated, when mothers were exposed to a single LPS injection early in pregnancy. Thus, LPS prenatal treatment resulted in (1) lower increased total and differential (macrophages, neutrophils, eosinophils and lymphocytes) BAL cellularity count; (2) increased number of total, mononuclear and polymorphonuclear cells in the peripheral blood; and (3) no differences in bone marrow cellularity or passive cutaneous anaphylaxis. SIGNIFICANCE: In conclusion, female pups treated prenatally with LPS presented an attenuated response to experimentally-induced asthma. We observed reduced immune cell migration from peripheral blood to the lungs, with no effect on the production of bone marrow cells or antibodies. It was suggested that inflammatory events such as exposure to LPS in early fetal life can attenuate allergic inflammation in the lung, which is a common symptom in asthma.

Inflammation and remodeling in infantile, juvenile, and adult allergic sensitized mice.

BACKGROUND: Airway structural changes occur early in childhood asthma, but it is unknown whether the development of airway alterations in children is similar to that of adults. We compared inflammation and remodeling parameters in allergic sensitized infantile, juvenile, and adult mice. METHODS: Infantile mice (18D) were sensitized with three intraperitoneal injections (i.p.) of ovalbumin (OVA) at days 5 and 7 and challenged with OVA at days 14-16. The 18D1 group received an additional challenge at days 9-11. The juvenile mice (40D) received challenges at days 22-24 and 36-38. Adult mice (100D) were sensitized at days 60-62 and received three inhalations at days 77-79 and 96-98. Animals were submitted to whole body plethysmography. Airway eosinophils, CD3+ T-lymphocytes, IL-5+ cells, mucus content, collagen and reticular fibers density, and smooth muscle thickness were quantified. RESULTS: All sensitized animals presented with airway hyperresponsiveness, without differences in eosinophil cell density. The density of CD3+ T-cells was higher in the 100D and 18D1 groups than in the 18D and 40D groups. Infantile sensitized groups demonstrated increased interleukin-5 expression in the airways. Infantile mice demonstrated more mucus in the bronchiolar epithelium than the 40D and 100D mice. The 18D animals demonstrated less collagen than the 18D1 group. Juvenile and adult mice had increased airway smooth muscle thickness when compared to age-matched controls, but no differences were observed in the infantile groups. CONCLUSION: We have shown that infantile mice develop inflammatory and structural alterations in the airways that are partially different from those developed in older animals.

Allergen-sensitization in vivo enhances mast cell-induced inflammatory responses and supports innate immunity.

Mast cells are immune cells that play a crucial role in inflammatory reactions related to allergic reactions and the defense against certain parasites and bacteria. In allergy, the binding of immunoglobulin E (IgE) to its high-affinity receptor (FcepsilonRI) sensitizes mast cells. Subsequent cross-linking of IgE-FcepsilonRI by multivalent antigen results in cellular activation and the release of proinflammatory mediators. Recent in vivo and in vitro experiments suggest that IgE not only acts as an allergen sensor, but also induces molecular and biological changes in mast cells. In the present study we examined whether allergen-sensitization in vivo could modify the magnitude of mast cells-induced inflammatory responses. Moreover, we studied changes in peritoneal mast cell number and histamine amount during and after sensitization. We provided evidence that sensitization, at the time of the maximum allergen-specific IgE-titer, increases the intensity of a local inflammatory process generated in a cutaneous anaphylactic reaction. Sensitization also supports innate immunity, improving survival and speeding up the resolution of an acute inflammatory reaction induced by polymicrobial sepsis, while decreasing the amount of histamine in peritoneal mast cells. In addition, our results showed that sensitization induces a late increase in the number and histamine amount of peritoneal mast cells. Thus, our findings clearly demonstrated that sensitization induces changes in mast cells which prepare the cell to induce more intense inflammatory responses. This entails an increased detrimental role in subsequent IgE-dependent allergic reactions and an improved protective function in innate defense against pathogens.

In vivo hydroquinone exposure impairs allergic lung inflammation in rats.

Hydroquinone (HQ) is naturally found in the diet, drugs, as an environmental contaminant and endogenously generated after benzene exposure. Considering that HQ alters the immune system and its several source of exposures in the environment, we hypothesized that prolonged exposure of HQ could affect the course of an immune-mediated inflammatory response. For this purpose, male Wistar rats were intraperitoneally exposed to vehicle or HQ once a day, for 22 days with a 2-day interval every 5 days. On day 10 after exposure with vehicle or HQ, animals were ovalbumin (OA)-sensitized and OA-aerosolized challenged on day 23. HQ exposure did not alter the number of circulating leukocytes but impaired allergic inflammation, evidenced by lower number of leukocytes in the bronchoalveolar lavage fluid 24h after OA-challenge. Reduced force contraction of ex vivo tracheal segments upon OA-challenge and impaired mesentery mast cell degranulation after in situ OA-challenge were also detected in tissues from HQ exposed animals. The OA-specificity on the decreased responses was corroborated by normal trachea contraction and mast cell degranulation in response to compound 48/80. In fact, lower levels of circulating OA-anaphylactic antibodies were found in HQ exposed rats, as assessed by passive cutaneous anaphylaxis assay. The reduced level of OA-anaphylactic antibody was not dependent on lower number or proliferation of lymphocytes. Nevertheless, lower expression of the co-stimulatory molecules CD6 and CD45R on OA-activated lymphocytes from HQ exposed rats indicate the interference of HQ exposure with signaling of the humoral response during allergic inflammation. Together, these data indicate specific effects of HQ exposure manifested during an immune host defense.

Creatine supplementation exacerbates allergic lung inflammation and airway remodeling in mice.

Creatine supplement is the most popular nutritional supplement, and has various metabolic functions and sports medicine applications. Creatine supplementation increases muscle mass and can decrease muscular inflammation. Some studies have also suggested a beneficial role of creatine supplementation on chronic pulmonary diseases such as chronic obstructive pulmonary disease and cystic fibrosis. Among athletes, the prevalence of asthma is high, and many of these individuals may be taking creatine. However, the effects of creatine supplementation on chronic pulmonary diseases of allergic origin have not been investigated. In the present study, we analyzed the effects of creatine supplementation on a model of chronic allergic lung inflammation. Thirty-one Balb/c mice were divided into four groups: control, creatine (Cr), ovalbumin (OVA), and OVA+Cr. OVA and OVA+Cr groups were sensitized with intraperitoneal injections of OVA on Days 0, 14, 28, and 42. OVA challenge (OVA 1%) and Cr treatment (0.5 g/kg/d) were initiated on Day 21 and lasted until Day 53. We determined the index of hyperresponsiveness, the serum levels of OVA-specific immunoglobulin (Ig)E and IgG(1), and the total and differential cell counts in bronchoalveolar lavage fluid. We also quantified airway inflammation, and the airway density of IL-4+, IL-5+, IL-2+, IFN-gamma+, and insulin-like growth factor (IGF)-1+ cells, collagen and elastic fibers, and airway smooth muscle thickness. Our results showed that creatine in OVA-sensitized mice increased hyperresponsiveness; eosinophilic inflammation; airway density of IL-4+, IL-5+, and IGF-1 inflammatory cells; airway collagen and elastin content; and smooth muscle thickness. The results show that creatine supplementation exacerbates the lung allergic response to OVA through a T helper cell type 2 pathway and increased IGF-1 expression.

Regulation of anaphylactic IgG1 antibody production by IL-4 and IL-10.

BACKGROUND: Different cytokines have been implicated in the regulation of isotype expression in primary and secondary antibody responses. The aim of this study was to assess the regulation of anaphylactic IgG1 and IgE antibodies by IL-4, IL-10 and IFN-gamma at different time points of the antibody response against PI, an immunosuppressive fraction of Ascaris suum extract, and ovalbumin (OVA). METHODS: Wild-type or cytokine-deficient C57BL/6 or BALB/c mice were immunized with PI or OVA in different adjuvants. Twenty days later, they were boosted with the respective antigen. IgG1 and IgE antibodies produced during primary and secondary responses were measured by passive cutaneous anaphylaxis. RESULTS: PI induced low levels of anaphylactic IgG1 antibodies in the primary response and moderate levels after the antigenic booster, which were IL-4-dependent. In the absence of IL-10 and IFN-gamma, PI-specific IgG1 and IgE enhanced significantly, indicating that these cytokines downregulated antibody production in primary and secondary responses. The IgG1 response to OVA in aluminium hydroxide or complete Freund's adjuvant was IL-4-dependent in the beginning of the primary response. Later on, it became only partially regulated by IL-4 in C57BL/6 mice and IL-4-independent in Th2-prone BALB/c mice. In contrast, IgE antibodies depended exclusively upon IL-4 during the entire time course. CONCLUSIONS: These results indicate, first, that the IL-4 dependency of anaphylactic IgG1 antibody production, mainly in the secondary response, varies among mouse strains, and, second, that the nature of the antigen determines whether IL-10 and IFN-gamma limit the potential to make large amounts of anaphylactic IgG1 and IgE.

BCG modulation of anaphylactic antibody response, airway inflammation and lung hyperreactivity in genetically selected mouse strains (Selection IV-A).

The effect of Bacillus Calmette-Guérin (BCG) treatment in allergic pulmonary reaction was studied in mice genetically selected accordingly to a High (H-IVA) or Low (L-IVA) antibody responsiveness. Mice were immunized with ovalbumin (OVA) or OVA plus BCG. Two days after nasal antigenic challenge, seric IgE and IgG1 anti-OVA, eosinophils in pulmonary tissue, inflammatory cells in bronchoalveolar lavage and the compliance and conductance of respiratory system were evaluated. H-IVA mice were found more susceptible than L-IVA, and BCG was able to inhibit simultaneously the production of IgE, the bronchopulmonary inflammation and bronchial hyperresponsiveness in these genetically selected mice.

Bacterial lipopolysaccharide signaling through Toll-like receptor 4 suppresses asthma-like responses via nitric oxide synthase 2 activity.

Asthma results from an intrapulmonary allergen-driven Th2 response and is characterized by intermittent airway obstruction, airway hyperreactivity, and airway inflammation. An inverse association between allergic asthma and microbial infections has been observed. Microbial infections could prevent allergic responses by inducing the secretion of the type 1 cytokines, IL-12 and IFN-gamma. In this study, we examined whether administration of bacterial LPS, a prototypic bacterial product that activates innate immune cells via the Toll-like receptor 4 (TLR4) could suppress early and late allergic responses in a murine model of asthma. We report that LPS administration suppresses the IgE-mediated and mast cell-dependent passive cutaneous anaphylaxis, pulmonary inflammation, airway eosinophilia, mucus production, and airway hyperactivity. The suppression of asthma-like responses was not due to Th1 shift as it persisted in IL-12(-/-) or IFN-gamma(-/-) mice. However, the suppressive effect of LPS was not observed in TLR4- or NO synthase 2-deficient mice. Our findings demonstrate, for the first time, that LPS suppresses Th2 responses in vivo via the TLR4-dependent pathway that triggers NO synthase 2 activity.

Anaphylaxis inhibitory factor in IgE-dependent mast cell stimulation.

We have previously demonstrated that there is a factor present in some human serum which inhibits the passive cutaneous anaphylaxis reaction mediated by IgE. The present study analyzes the effect of this factor on mast cell IgE-dependent tumor necrosis factor (TNF)-alpha release. Rat peritoneal mast cells and RBL-2H3 cells treated with monoclonal mouse IgE anti-dinitrophenol (anti-DNP) followed by DNP-bovine serum albumin (DNP-BSA) were used and TNF-alpha release was measured at different time points. Similarly the percentage of rat peritoneal mast cell degranulation was determined. Results show a period of 30 min as optimal incubation time for TNF-alpha release in both mast cell populations. Human serum anaphylaxis inhibitory factor enriched fraction inhibited TNF-alpha release when it was in contact with IgE before the antigen treatment. Under these conditions the percentage of mast cell degranulation decreased. Mast cells incubated before IgE treatment with the factor alone do not release TNF-alpha and the percentage of degranulation increases due to a non-IgE-dependent process. A possible role of the inhibitory factor in the later phase reaction in addition to immediate hypersensitivity described previously is suggested.

Anaphylactic reaction in experimental malnutrition.

We evaluated the effects of malnutrition on the allergic response in male EPM-1 Wistar rats. The animals underwent two dietary regimens from the 21st to the 60th day of life as follows: control animals were fed a normoproteic diet (18% casein) and malnourished animals a hypoproteic diet (4.5% casein). On day 60, some of the animals were sacrificed for determination of total serum protein and albumin levels. In addition, within each subgroup of the remaining animals, some underwent intraperitoneal immunization with ovalbumin in aluminum hydroxide. Thus, four groups of animal were obtained: immunized controls (n = 11); immunized malnourished animals (n = 11); unimmunized controls (n = 7) and unimmunized malnourished rats (n = 8). Fourteen days after sensitization with ovalbumin, the animals were challenged with intravenous ovalbumin in order to induce an anaphylactic reaction, which was evaluated by vascular permeability increase as assessed by the Evans blue dye extravasation method. Extravasation of Evans blue was quantitated in dried gastrointestinal tissues obtained from rats sacrificed 10 min after induction of the anaphylactic reaction. Passive cutaneous anaphylaxis (PCA) reactions were also evaluated in the controls and malnourished rats. The adequacy of our model was confirmed by the reduction in weight gain, in food intake, and in total protein and albumin serum levels in malnourished rats as compared to controls at 60 days of life. The anaphylactic reaction induced significant increase in vascular permeability particularly among control animals. PCR results showed significantly lower titers in malnourished animals when their sera were injected into the skin of control animals. In contrast, PCA reactions using sera from immunized control rats to inject into the skin of malnourished rats showed an equally intense reaction as that observed in control animals. Our results suggest that malnourished animals have a normal capacity of releasing inflammatory mediators, and show a normal vascular response after anaphylaxis. The diminished vascular response seen in the gastrointestinal tract in malnourished animals, as compared to controls, may be due to the production of lower levels of IgE antibodies caused by malnutrition.

Impairment in connective tissue mast cells degranulation in spontaneously hypertensive rats: stimulus dependent resistance.

1. Microvascular permeability in the mesentery and consequent leakage of protein into the peritoneum of spontaneously hypertensive rats (SHR) and normotensive rats (NTR) was measured in vivo by the extravasation of Evans blue dye. 2. In sensitized NTR, challenge with antigen produced extensive increases in dye extravasation in the mesentery and in peritoneal lavage fluid within 10 min. 3. In sensitized SHR there was no increase in the permeability of the mesentery and a very weak increase in dye extravasation in the peritoneal cavity following challenge. 4. The glucocorticoid antagonist RU38486 did not change the permeability response induced by antigen in sensitized NTR and SHR. 5. However, compound 48/80 was equally effective in either NTR or SHR in causing increased vasopermeability. 6. Mesenteric mast cells in the NTR were degranulated after immunological challenge, whereas those in the SHR were resistant, as measured histologically. 7. Similarly, challenge ex vivo of mesentery from sensitized NTR induced contraction of guinea-pig ileum in co-incubation experiments, whereas SHR mesentery was unresponsive. 8. Plasma levels of antigen-specific IgE and IgG2a in sensitized NTR and SHR were identical. 9. Immune serum from SHR was unable to induce a passive cutaneous anaphylaxis (PCA) reaction in the skin of NTR and SHR did not develop a PCA reaction upon passive sensitization with NTR immune serum. 10. We conclude that the mast cells of SHR are resistant to degranulation following immunological challenge, although the relevant antibodies are present.

Decrease in passive cutaneous anaphylaxis reactions in rats secondary to stress.

Anaphylaxis was assayed by the passive cutaneous anaphylaxis (PCA) test in male Wistar rats (250 g body weight). Three experimental groups were used: animals restrained in an electric chamber and submitted to electric shock immediately after sensitization and 24 h before anaphylaxis (31 animals), animals restrained in the electric chamber for the same time but receiving no electric shock (23 animals), and non-manipulated, home-cage control animals (24 animals). The frequency of PCA reactions was decreased in the group of animals submitted to restraint when compared with the home-cage control group. However, the group of animals submitted to both restraint and electric shock showed no decrease in the frequency of PCA reactions. It is suggested that, in rats, stress induced by restraint decreases PCA reactions and that this decrease is counteracted by a simultaneous stress induced by electric shock.

Decrease in passive cutaneous anaphylaxis reactions in rats secondary to stress

Anaphylaxis was assayed by the passive cutaneous anaphylaxis (PCA) test in male Wistar rats (250 g body weight). Three experimental groups were used: animals restrained in an electric chamber and submitted to electric shock immediately after sensitization and 24 h before anaphylaxis (31 animals), animals restrained in the electric chamber for the same time but receiving no electric shock (23 animals), and non-manipulated, home-cage control animals (24 animals). The frequency of PCA reactions was decreased in the group of animals submitted to restraint when compared with the home-cage control group. However, the group of animals submitted to both restraint and electric shock showed no decrease in the frequency of PCA reactions. It is suggested that, in rats, stress induced by restraint decreases PCA reactions and that this decrease is counteracted by a simultaneous stress induced by electric shock

Effect of purified components of Ascaris suum extracts on IgE antibody response in guinea pigs.

The effect of components P530 and P29, isolated from Ascaris suum adult worm extract (ASC), on the heterologous IgE antibody response was studied in guinea pigs. Groups of 7 guinea pigs were immunized ip with 50 micrograms of ovalbumin (OA) alone or mixed with 200 micrograms of each component precipitated in an alum gel. The primary and secondary IgE antibody response was evaluated by passive cutaneous anaphylaxis reaction (PCA). Immunization of guinea pigs with P29 plus ovalbumin (OA) resulted in a significant increase in the level of serum IgE anti-OA antibodies, especially in the secondary response (almost 8-fold higher when compared with control group). This potentiated response was not observed when the animals received OA plus P530 or the crude extract. Indeed, the P530 component, as well as the crude extract, induced a depression of the anti-OA IgE antibody response (2-3 fold decrease when compared with OA-immunized animals). It was also shown that P29, but not P530 or ASC, was capable of eliciting a strong anti-ASC IgE antibody response. These results demonstrate that in guinea pigs these two Ascaris suum components have antagonistic biological effects, one inducing potentiation and the other suppression of the heterologous IgE antibody response.

An allergenic 2S storage protein from Ricinus communis seeds which is a part of the 2S albumin precursor predicted by c-DNA data.

1. A 1.9S albumin having allergenic activity and denoted Ric c III was isolated from an alcohol extract of defatted Ricinus communis seeds, CB-1A, as a homogeneous protein by ion-exchange chromatography on SP-Sephadex, gel filtration on Sephadex G-75 and preparative polyacrylamide gel electrophoresis (6 mg Ric c III/g CB-1A). 2. The protein contained approximately 98 amino acid residues distributed in 2 chains of 67 and 34 residues, a molecular weight of 11,239 based on amino acid composition and pI = 4.9 Ric c III can be aligned, on the basis of amino acid composition and partial amino acid sequence data, with residues 18 to 50 (51) and 66 to 130 of the 2S albumin precursor predicted by the cDNA data of S.D. Irwin, J.N. Keen, J.B.C. Findlay and J.M. Lord (Molecular and General Genetics, 222: 400-408, 1990). 3. The present data identify Ric c III as the second allergenic 2S storage albumin coded by this DNA.

Effect of purified components of Ascaris suum extracts on IgE antibody response in guinea pigs

The effect of components P530 and P29, isolated from Ascaris suum adult worm extract (ASC), on the heterologous IgE antibody response was studied in guinea pigs. Groups of 7 guinea pigs were immunized ip with 50 micrograms of ovalbumin (OA) alone or mixed with 200 micrograms of each component precipitated in an alum gel. The primary and secondary IgE antibody response was evaluated by passive cutaneous anaphylaxis reaction (PCA). Immunization of guinea pigs with P29 plus ovalbumin (OA) resulted in a significant increase in the level of serum IgE anti-OA antibodies, especially in the secondary response (almost 8-fold higher when compared with control group). This potentiated response was not observed when the animals received OA plus P530 or the crude extract. Indeed, the P530 component, as well as the crude extract, induced a depression of the anti-OA IgE antibody response (2-3 fold decrease when compared with OA-immunized animals). It was also shown that P29, but not P530 or ASC, was capable of eliciting a strong anti-ASC IgE antibody response. These results demonstrate that in guinea pigs these two Ascaris suum components have antagonistic biological effects, one inducing potentiation and the other suppression of the heterologous IgE antibody response