Latex antigens induce IgE and eosinophils in mice

Characterization of the allergenic potential of proteins: an assessment of the kiwifruit allergen actinidin

Assessment of the potential allergenicity (IgE-inducing properties) of novel proteins is an important challenge in the overall safety assessment of foods. Resistance to digestion with pepsin is commonly measured to characterize allergenicity, although the association is not absolute. We have previously shown that specific IgE antibody production induced by systemic [intraperitoneal (i.p.)] exposure of BALB/c strain mice to a range of proteins correlates with allergenic potential for known allergens. The purpose of the present study was to explore further the utility of these approaches using the food allergen, actinidin. Recently, kiwifruit has become an important allergenic foodstuff, coincident with its increased consumption, particularly as a weaning food. The ability of the kiwifruit allergen actinidin to stimulate antibody responses has been compared with the reference allergen ovalbumin, and with the non-allergen bovine haemoglobin. Haemoglobin was rapidly digested by pepsin whereas actinidin was resistant unless subjected to prior chemical reduction (reflecting intracellular digestion conditions). Haemoglobin stimulated detectable IgG antibody production at relatively high doses (10%), but failed to provoke detectable IgE. In contrast, actinidin was both immunogenic and allergenic at relatively low doses (0.25% to 1%). Vigorous IgG and IgG1 antibody and high titre IgE antibody responses were recorded, similar to those provoked by ovalbumin. Thus, actinidin displays a marked ability to provoke IgE, consistent with allergenic potential. These data provide further encouragement that in tandem with analysis of pepsin stability, the induction of IgE after systemic exposure of BALB/c strain mice provides a useful approach for the prospective identification of protein allergens.

A latex-induced allergic airway inflammation model in mice

Latex allergy is important due to serious health impacts and widespread use of its products. Latex allergic reactions can be induced in skin and mucosal surfaces including the respiratory tract. The development of murine models of allergic airway inflammation has provided a framework to dissect out the cellular and molecular mechanisms of allergic respiratory inflammation. In this study we have developed a new mouse model of latex allergic airway inflammation using aerosol inhalation. The allergic inflammatory responses were characterized in this model. Mice were injected intraperitoneally with 0, 10, 50, or 200 microg of latex extract and their serum anti-latex IgE titers were determined. In the second stage, a standard protocol of inhalation was designed and three doses of latex extract solutions including 1%, 0.1%, and 0.01% were used to induce allergic airway inflammation. Bronchoalveolar lavage cytokines (IL-5 and IL-13) and serum anti-latex IgE and IgG(1) titers were determined by ELISA. Eosinophil levels in lung, peripheral blood, bronchoalveolar lavage and bone marrow were also evaluated. Histological analysis of lung tissue was also performed after latex inhalation. The aerosol inhalation of 1% latex allergens solution and presensitization with 50 mug of latex in this study resulted in the development of allergic airway inflammation characterized by elevated allergen specific IgE and IgG(1), peripheral blood, bronchoalveolar lavage and bone marrow eosinophilia. Histological analysis of the lung revealed an inflammatory response characterized by eosinophil accumulation. Elevated levels of Th2 cytokines IL-5 and IL-13 also were shown in bronchoalveolar lavage samples. These studies demonstrate that sensitization and subsequent aerosol inhalational challenge of latex allergen extract promotes allergic airway inflammation characterized by elevated IL-5 and IL-13 and eosinophils.

Immune response modulation by curcumin in a latex allergy model

Background

There has been a worldwide increase in allergy and asthma over the last few decades, particularly in industrially developed nations. This resulted in a renewed interest to understand the pathogenesis of allergy in recent years. The progress made in the pathogenesis of allergic disease has led to the exploration of novel alternative therapies, which include herbal medicines as well. Curcumin, present in turmeric, a frequently used spice in Asia has been shown to have anti-allergic and inflammatory potential.

Methods

We used a murine model of latex allergy to investigate the role of curcumin as an immunomodulator. BALB/c mice were exposed to latex allergens and developed latex allergy with a Th2 type of immune response. These animals were treated with curcumin and the immunological and inflammatory responses were evaluated.

Results

Animals exposed to latex showed enhanced serum IgE, latex specific IgG₁, IL-4, IL-5, IL-13, eosinophils and inflammation in the lungs. Intragastric treatment of latex-sensitized mice with curcumin demonstrated a diminished Th2 response with a concurrent reduction in lung inflammation. Eosinophilia in curcumin-treated mice was markedly reduced, co-stimulatory molecule expression (CD80, CD86, and OX40L) on antigen-presenting cells was decreased, and expression of MMP-9, OAT, and TSLP genes was also attenuated.

Conclusion

These results suggest that curcumin has potential therapeutic value for controlling allergic responses resulting from exposure to allergens.

Gastro-Intestinal Exposure to Latex Antigens Induce Allergic Responses in Mice

BACKGROUND

Natural rubber latex (NRL) has emerged as a major cause of respiratory allergy among specific exposed groups of individuals. Since latex allergens are dispersed in the environment it is conceivable that latex proteins are both inhaled and ingested. The mechanism of latex allergy and the immune responses following reexposure of latex allergens by the intranasal route was studied in a murine model of latex allergy developed by intragastric sensitization with NRL.

METHODS

BALB/c mice were sensitized intragastrically ('ig'), intranasally ('in') or 'ig' followed by 'in' challenge with NRL allergens. The cellular and humoral immune responses, lung function and histological changes were determined.

RESULTS

Peripheral blood eosinophilia was observed in the 'ig' and 'ig/in'-NRL-sensitized animals in comparison to normal controls (p < 0.05). The 'ig' group showed a marked increase over control mice in serum total IgE, NRL-specific IgG and IgG subclasses (p < 0.05). Increased levels of IL-4, IL-5, IL-10, and IL-13 were detected in 'ig'-NRL-sensitized mice. Intranasal exposure with NRL after 'ig' sensitization further enhanced the cytokine levels. A tendency towards enhanced stimulation was determined in 'ig'-sensitized mice; a significant difference was shown in the 'ig/in'-group (p < 0.05). Increased airway hyperreactivity was found in 'ig'-NRL-sensitized-mice (15.1 +/- 2.5 vs. 8.9 +/- 1.7 cm H2O x ml(-1) x s, p < 0.05). Mucus secretion from jejunal epithelium and eosinophilic infiltration into the jejunal lamina propria were observed in the 'ig'-NRL-sensitized-mice.

CONCLUSIONS

The results demonstrate that intragastric NRL sensitization did not induce specific tolerance, and additional intranasal exposure with latex allergens resulted in systemic allergic manifestations in the murine model.

Animal models of type I allergy using recombinant allergens

Various animal models including guinea pigs, monkeys, dogs, rats, and mice have been established in an attempt to provide insights into the complex immunological and pathophysiological mechanisms of human type I allergic diseases. The detailed knowledge of the murine genome, the various components of the murine immune system, and the generation of engineered mice has made the murine system the most attractive among all animal models. The availability of multitude technologies and reagents to characterize and manipulate immunological pathways and mediators adds to the outstanding opportunities to assess the pathology of allergic diseases and to develop novel therapeutic strategies in mice. Numerous sensitization protocols with food and aero-allergens are used to establish an allergic/asthma-like phenotype in mice. Requirements for an appropriate murine model include a close resemblance to the pathology of the disease in humans, the objective measurement of the physiologic parameters, as well as reliability and reproducibility of the experimental data. With respect to reproducible experimental conditions, it has been recognized that extract preparations from natural allergen sources can vary in their allergen-content and -composition. This might influence the degree of sensitization or the outcome of treatment strategies in dependence of the applied extract preparation. The use of recombinant allergens in experimental in vivo and in vitro systems can overcome these problems. Another aspect, that has become obvious from the experimental studies, is that allergens can differ in their immunogenicity as well as in their capacity to act as tolerogens. Therefore, it seems important that the efficacy of the different allergen-molecules to act as therapeutic agents is individually examined. In this review, examples of animal models are described, in which recombinant allergens have been used for sensitization and/or treatment of allergic responses and how they have been used to enhance our understanding of the pathology of allergic diseases.

Inhaled cornstarch glove powder increases latex-induced airway hyper-sensitivity in guinea-pigs

BACKGROUND

Breathing is one of the most important modes of sensitization to natural rubber latex (NRL) for health-care workers, a group most at risk. Cornstarch powder (CSp) from medical powdered NRL gloves is known to be an allergen carrier, and sensitization to NRL can occur by inhaling airborne particles from such gloves.

OBJECTIVE

The aim of this study was to demonstrate, using an experimental model, which CSp may act as an adjuvant in NRL-induced airway hyper-responsiveness.

METHODS

Guinea-pigs were exposed to aerosolized NRL-contaminated CSp or to NRL in saline solution for 1 h every day for 2 weeks. The control groups were exposed either to CSp or to saline alone. An additional group of guinea-pigs was exposed to aerosolized ovalbumin (OVA) in saline. Three weeks after the last exposure, specific bronchial challenges were performed. In addition, Specific IgG and IgG1 in sera and thromboxane (Tx) B(2) levels in bronchoalveolar lavage fluid (BALF) were measured.

RESULTS

The NRL challenge caused significant bronchospasm in the animals that had been exposed to NRL compared with those in the control groups (P<0.02). Guinea-pigs exposed to OVA also demonstrated a significant bronchospasm after OVA challenge (P<0.001). The guinea-pigs that had inhaled NRL-contaminated CSp had a significantly higher bronchoconstriction level than those that had inhaled NRL alone (P<0.02). Specific IgG and IgG1 were undetectable in sera from all groups, whereas significant amounts of TxB(2) (P<0.001) were found in the lungs of the guinea-pigs exposed to NRL or OVA.

CONCLUSION

Inhaling CSp increases the airway response to NRL. The fact that specific IgG and IgG1 were not detected might be the result of an immune response limited to the airways. This finding is supported by a significant increase of TxB(2) level in the BALF of sensitized guinea-pigs.

Induction of mucosal tolerance with recombinant Hev b 1 and recombinant Hev b 3 for prevention of latex allergy in BALB/c mice

The prevalence of type I allergy to Hevea brasiliensis latex is particularly high among individuals with frequent exposure to latex products, such as health-care workers (HCW) and patients with spina bifida (SB). Treatment of latex allergy seems problematic as preventive measures, such as allergen avoidance, are not always possible and conventional immunotherapy with standardized latex extracts is not performed routinely. Thus, the aim of the present study was to establish a mouse model of latex allergy using two major latex allergens for HCWs and SB patients, Hev b 1 and Hev b 3, for sensitization. Prophylactic measures on the basis of mucosal tolerance induction with the recombinant allergens were tested in this model. Female BALB/c mice immunized intraperitoneally with recombinant (r)Hev b 1 or rHev b 3 displayed strong immune responses in vivo and in vitro. Intranasal treatment with rHev b 1 and rHev b 3 prior to sensitization led to reduced allergen-specific IgG1/IgE levels and significantly suppressed allergen-induced basophil degranulation. Moreover, lymphocyte proliferation and cytokine production (IL-4, IL-5, IFN-gamma) in vitro were significantly suppressed after pretreatment with both allergens. Suppressive cytokines, such as interleukin (IL)-10 and transforming growth factor (TGF)-beta, remained unchanged after the intranasal pretreatment, indicating mechanism of anergy rather than active immunosuppression. Taken together, these results suggest that mucosal tolerance induction with recombinant allergens could present a promising prevention strategy against latex allergy.

Characterization of a mouse model of allergy to a major occupational latex glove allergen Hev b 5

Allergen-specific immunotherapy is a clinically proven effective treatment for many allergic diseases, including asthma; however, it is not currently available for latex allergy because of the high risk of anaphylaxis. There is, therefore, a crucial need for an animal model of latex allergy in which to develop effective immunotherapy. Previous mouse models of latex allergy either did not characterize the allergic pulmonary immune response or used crude latex extracts, making it difficult to quantify the contribution of individual proteins and limiting their usefulness for developing specific immunotherapy. We immunized mice with recombinant Hev b 5, a defined major latex allergen, or latex glove protein extract, representing the range of occupationally encountered processed latex allergens. The immune response was compared with that seen in ovalbumin-immunized mice. Immunization with Hev b 5 or glove extract elicits hallmarks of allergic pulmonary Th2-type immune responses, comparable to those for ovalbumin, including (1) serum antigen-specific IgE, (2) an eosinophilic inflammatory infiltrate in the lung, (3) increased interleukin-5 in lung bronchoalveolar lavage fluid, and (4) mucus hypersecretion by epithelial cells in the lung airways. This mouse model will aid the development of potentially curative treatments for latex-sensitized individuals, including those with occupational asthma.

Epicutaneous natural rubber latex sensitization induces T helper 2-type dermatitis and strong prohevein-specific IgE response

In addition to immediate type I allergy symptoms, natural rubber latex allergy may manifest as protein contact dermatitis on the hands of health-care workers and other natural rubber latex glove users. We examined whether repeated application of natural rubber latex on mouse skin causes sensitization to natural rubber latex and dermatitis. Epicutaneous sensitization with natural rubber latex produced a significant influx of mononuclear cells, CD4+ CD3+ cells, and eosinophils to the sensitized skin sites. The number of degranulated mast cells in natural rubber latex-sensitized skin sites was significantly higher compared with control sites treated with phosphate-buffered saline. The expression of interleukin-1beta and interleukin-4 mRNA was markedly increased in natural rubber latex-sensitized skin sites. Moreover, significant increases in the mRNA expression of chemokines CCL2 (monocyte chemoattractant protein-1), CCL11 (eotaxin-1), CCL3 (macrophage inflammatory protein-1alpha), and CCL4 (macrophage inflammatory protein-1beta) were found. In addition to the cutaneous inflammatory response, epicutaneous sensitization with natural rubber latex induced a striking increase in the total and specific immunoglobulin E levels but not in the immunoglobulin G2a levels. Intraperitoneal immunization with natural rubber latex induced a strong natural rubber latex-specific immunoglobulin G2a response, but only a weak immunoglobulin E response. We also studied the role of two major natural rubber latex allergens, the highly hydrophilic prohevein and the hydrophobic rubber elongation factor. Cutaneous application of natural rubber latex elicited a strong immunoglobulin E response against prohevein, but not against rubber elongation factor. On the contrary, intraperitoneal immunization with natural rubber latex elicited strong immunoglobulin G2a production to rubber elongation factor but not to prohevein. These results demonstrate that epicutaneous sensitization with natural rubber latex induces T helper 2-dominated dermal inflammation and strong immunoglobulin E response in this murine model of natural rubber latex induced protein contact dermatitis. Epicutaneous sensitization to natural rubber latex proteins eluting from latex gloves may therefore contribute to the development of hand dermatitis and also natural rubber latex-specific immunoglobulin E antibodies.

Immunoadjuvant properties of glove cornstarch powder in latex-induced hypersensitivity

BACKGROUND

Cornstarch powder present in medical gloves plays an important role in latex-induced hypersensitivity as allergen carrier either, by the inhalation route, by skin contact or by direct contact with mucous membranes.

OBJECTIVE

Our objective was to test the hypothesis that cornstarch could act as an immunoadjuvant in immediate type-I latex-induced hypersensitivity.

METHODS

Guinea-pigs were sensitized by intraperitoneal route with two different antigens (latex proteins and ovalbumin) with or without cornstarch powder. Airway responsiveness after specific bronchial provocation was evaluated and specific IgG and IgG1 levels were determined by enzyme-linked immunosorbent assay (ELISA). Controls were treated with cornstarch powder or saline alone.

RESULTS

Animals sensitized with latex proteins (n = 7 in each group) showed significant bronchoconstriction (P < 0.03) and higher anti-latex antibody levels than the controls (P < 0.005). Guinea-pigs sensitized with latex-contaminated cornstarch had higher levels of specific antibodies than those sensitized with latex alone (P < 0.05). Animals sensitized to latex mixed with cornstarch showed higher bronchospasm than those treated with latex alone (P < 0.003). Animals sensitized to ovalbumin mixed with cornstarch also showed higher antibody and bronchoconstriction levels (P < 0.05) than those immunized with ovalbumin alone but antibody titres were significantly lower than those of the animals treated with ovalbumin and Freund's complete adjuvant (P < 0.01; n = 5 in each group).

CONCLUSION

Our findings show that cornstarch powder increases antigen-induced bronchoconstriction and antibody production. This role of immunoadjuvant is not antigen-specific. The cornstarch powder used as donning agent in latex gloves is an allergen carrier and it can enhance latex-induced hypersensitivity.

Bacterial protease treatment of natural rubber latex alters its primary immunogenicity in a mouse model of sensitization

The purpose of the present investigation was to determine whether enzyme-treated (ET)-NRL is less immunogenic than untreated NRL in a BALB/c mouse model of primary in vivo sensitization following repeated subcutaneous injections with the aqueous phase of ammoniated NRL or ET-NRL. Mice immunized with NRL produced IgE against NRL and ET-NRL, indicating that protease treatment did not completely destroy IgE antibody epitopes. In contrast, ET-NRL-immunized mice did not produce IgE against either NRL or ET-NRL, suggesting that enzyme treatment reduced the number of antigenic polypeptides associated with NRL below the threshold for sensitization. Thelper-lymphocytes from NRL-immunized mice proliferated and produced IL-4 when stimulated in vitro with polypeptides from NRL, but not ET-NRL. In contrast, Thelper-lymphocytes from ET-NRL-immunized mice were nonresponsive to ET-NRL or NRL. We conclude that lack of IgE production by ET-NRL-immunized mice is likely related to a lack of T-cell help in the form of IL-4, rather than enzyme digestion of IgE antibody epitopes. These data indicate that there is an immunologic rationale for production of enzyme-treated NRL-containing medical devices.

Hypersensitivity reactions after respiratory sensitization: effect of intranasal peptides containing T-cell epitopes

BACKGROUND

The intranasal administration of peptides containing T-cell epitopes has been shown to inhibit T-cell and antibody responses of mice injected with allergen, but responses to respiratory sensitization might be regulated differently.

OBJECTIVE

This study was designed to examine the effect of intranasal peptide on antigen-induced lung inflammatory responses and delayed hypersensitivity after sensitization by the respiratory mucosa or without sensitization.

METHODS

Mice were treated with an intranasal tolerizing regimen of a peptide containing the major T-cell epitope of Der p 1. Delayed hypersensitivity and lung inflammation to challenge with Der p 1 was measured either without further treatment or after sensitization induced by means of the intranasal administration of Der p 1 with a mutated enterotoxin adjuvant. Lung inflammatory responses were examined by means of lavage and histologic section, and delayed hypersensitivity responses were measured on the basis of ear swelling.

RESULTS

Delayed hypersensitivity reactions were induced in mice treated with intranasal peptide, and large reactions were found in mice given intranasal peptide and sensitized with intranasal Der p 1 and adjuvant. Mice pretreated with peptide and sensitized with Der p 1 had an increased lymphocytic infiltration after allergen-specific challenge, as measured by means of bronchoalveolar lavage and shown histologically. These hypersensitivity results are in contrast to previous data that show tolerance to injected antigen.

CONCLUSIONS

Although the intranasal administration of a peptide containing a T-cell epitope markedly inhibits responses to sensitization produced by the injection of allergen, the peptide induces immune responses and increases hypersensitivity to respiratory sensitization.

Latex allergy: past and present

Although latex products have been in use for over a century, allergic responses to latex proteins have only been recognized as a serious health problem for the past 15 years. Latex allergy particularly affects two groups, health care workers (HCW) and children with spina bifida (SB). This manuscript provides a brief history of latex allergy, and a review of the following: the manufacturing process for dipped latex products, the 11 latex allergens that have been characterized and received allergen designations by the International Union of Immunological Societies, the methods used in exposure assessment, the epidemiology and clinical management of latex allergy, and the use of animal models in investigating mechanisms underlying latex allergy.

The search of latex sensitization in spina bifida: diagnostic approach

BACKGROUND

Sensitization to latex has become a major problem in children with spina bifida. Life-threatening reactions may occur in these patients, therefore the search of latex sensitization must be an active task in all of these children.

OBJECTIVE

To design an approach for the diagnosis of latex sensitization in children with spina bifida.

METHODS

We studied 100 consecutive unselected patients. Skin prick tests with a commercial latex extract were performed, latex-specific serum immunoglobulin (Ig) E was determined by CAP test, and risk factors were studied. Originally, patients with an area of latex skin test > 50% of the area of histamine and/or CAP class > or = 3 were considered sensitized to latex. Diagnostic tests were also performed in a control group of 51 atopic and nonatopic children.

RESULTS

After performing a receiver-operating characteristics curve for both tests we recommend skin tests > 25% of the area of histamine (sensitivity - SEN = 79%, specificity - SPE = 100%, positive predictive value - PPV = 100%, negative predictive value - NPV = 90%), or CAP class > or = 2 (SEN = 88%, SPE = 100%, PPV = 100%, NPV = 94%) as diagnostic cut-off points. The anamnesis had a SEN of 44% for diagnosis, and a SPE of 100%. Latex sensitization was associated with more than 5 operations (OR = 8, 95% CI = 3-21.3), a personal history of atopy (OR = 11.5, 95% CI = 2.3-57.1), and serum total IgE > or = 2 z-units (OR = 4, 95% CI = 1. 6-10).

CONCLUSION

For the routine evaluation of children with spina bifida, we propose a diagnostic algorithm with skin prick tests as a first step and CAP second.

Latex allergy

Coined the next major health concern of the decade, allergy to natural rubber latex affects people routinely exposed to rubber products. Groups at highest risk include health care workers, rubber industry workers, and persons who have undergone multiple surgical procedures, especially those with spina bifida. Allergy to latex is a type I, immediate, IgE-mediated reaction, which can lead to anaphylaxis and death. Much of latex research is published in allergy journals. Dermatologists may not be aware of the prevalence, symptoms, risks, diagnosis, and treatment of latex allergy. These topics are the subject of this review. Research concerning antigenic proteins, as well as sources of latex alternatives, is also summarized. (J Am Acad Dermatol 1998;39:1-24.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants should have a clear understanding of the history, biology, epidemiology, mechanism, clinical characteristics, diagnostic work-up, and treatment of latex allergy. Readers should also have a greater understanding of multiple potential allergenic latex proteins and their importance in preventing future latex-sensitization.

Anti-interleukin (IL)-4 and -IL-5 antibodies downregulate IgE and eosinophilia in mice exposed to Aspergillus antigens

The effect of multiple divided doses compared with single-dose injections of antibodies to murine interleukin (IL)-4 and IL-5 in their respective downregulation of IgE and eosinophilia developing in a model of allergic aspergillosis is investigated. BALB/c mice were exposed to Aspergillus fumigatus antigens (Af) before and along with anticytokine antibodies. The kinetics of blood eosinophils, eosinophil peroxidase (EPO) in bone-marrow cells, serum levels of IgE and Af-specific antibodies, Af-induced cytokine production and mRNA, and lung histology were studied. The results indicate that only multiple anti-IL-5 antibodies were effective in maintaining baseline levels of blood eosinophils. Multiple anti-IL-4 antibodies also downregulated eosinophils in the bone marrow, lung, and peripheral blood, although to a lesser extent than in anti-IL-5 antibody-injected mice. Significant correlation between the EPO activity and the eosinophil numbers in anticytokine antibody-treated mice was observed. The different anti-IL-4 antibody treatments downregulated IgE to the same extent. We conclude that multiple divided doses of anti-IL-5 antibodies are required to sustain normal eosinophil levels in murine allergic aspergillosis. This information may be significant in the therapy of pulmonary allergic diseases.

Immunopathologic responses to Aspergillus antigen in interleukin-4 knockout mice

Two strains of interleukin-4 (IL-4) gene knockout mice were studied and compared with wild strains to determine the role of IL-4 in the immunopathogenesis of murine allergic aspergillosis. Animals immunized intraperitoneally were subsequently challenged with Aspergillus antigen intranasally. The animals were evaluated for total serum immunoglobulin E (IgE) levels, Aspergillus-specific IgG antibody isotypes, peripheral blood eosinophils, cytokine and chemokine mRNA transcripts in spleen cells, and pulmonary histology. No serum IgE was detected in animals deficient in the IL-4 gene. Aspergillus-specific IgG1 was detected in all animals, while enhanced levels of IgG2a were detected in IL-4 knockout animals challenged with A. fumigatus antigen. There were no differences in the peripheral blood or lung eosinophils in the two groups of mice exposed to A. fumigatus. These results indicate that lung injury in Aspergillus-antigen challenged animals may be the result of the eosinophil mediators and that IgE-mediated injury may not be significant in this model, which may be a significant variation between the model and human allergic aspergillosis.

Development of bone marrow eosinophilia in mice induced by Aspergillus fumigatus antigens

A model of allergic bronchopulmonary aspergillosis (ABPA) developed by exposing mice to Aspergillus fumigatus antigen (Af) exhibits peripheral blood (PB), lung, and bone marrow (BM) eosinophilia. Because the BM is a site of eosinophilopoiesis, we have investigated the role of Af in the induction of this process in the BM. Groups of mice were exposed intranasally (i.n.) or intraperitoneally (i.p.) to Af. BM cells from mice were cultured with either Af or allogenic spleen cell supernatant stimulated with Af. Eosinophil counts in different lymphoid compartments, eosinophil peroxidase (EPO), and mRNA for cytokines and IgE in BM cells were studied. Results indicate that the eosinophil numbers were significantly elevated in PB and BM of all Af-exposed mice. Lung lavage eosinophils increased only in the i.n. group. Af induced EPO activity only in BM cultures from Af-exposed mice. The EPO activity was further enhanced by supernatants from spleen cells from Af-exposed mice. mRNA transcription of IL-3 and IL-5 were measurable in BM cells of the ip exposed mice. These findings suggest that Af mediates eosinophil development in BM of mice and this process is promoted by hematopoietic factors generated within the BM and in other lymphoid tissue such as the spleen.

Aspergillus fumigatus peptides differentially express Th1 and Th2 cytokines

Relevant allergens from Aspergillus fumigatus associated with allergic bronchopulmonary aspergillosis (ABPA) have been cloned and expressed. The pathogenesis of ABPA probably depends on specific cytokines and immunoglobulins secreted by lymphocytes on stimulation with different epitopes of those allergens. In the present study, we synthesized peptides of 12-16 amino acids from the sequence of Asp fI and compared their immunological responses in four mice strains (BALB/c, C57BL/6, AKR, and CBA). Of the five peptides studied for their cytokine profile, one showed a clear Th1, whereas another showed a Th2 response. The remaining three peptides varied in their immunoreactivity. The results suggest that a number of epitopes of diverse activities are present in individual molecules and may be involved in the pathogenesis of ABPA through differential cytokine secretions.

Latex allergen in respirable particulate air pollution

OBJECTIVE

Urban air samples contain numerous irregular respirable black particles, which may be airborne tire fragments. A major component of tires is natural latex. Proteins of natural latex can act as adjuvants and as antigens capable of eliciting immediate hypersensitivity, making their presence in particulate air pollution an important clinical issue.

METHODS

Particulate air pollutants were collected by volumetric sampling devices and characterized by optical microscopy, chemical solubility tests, and mass spectrometry. Extracts of rubber tire fragments were tested for elutable latex antigens by antibody inhibition assays.

RESULTS

Identification of latex in air samples and milled material from automobile tires was supported by mass spectrometry results and was further confirmed by physical appearance and chemical solubility studies. Competitive immunoassay confirmed the presence of extractable latex antigens from rubber tire fragments.

CONCLUSIONS

Latex antigens are extractable from rubber tire fragments, which are abundant in urban air samples. Given the adjuvant and sensitizing effects of latex, these airborne particles could contribute, through direct and indirect mechanisms, to the increase in both latex sensitization and asthma. The impact of these particles should be considered in the issue of morbidity and mortality rates associated with respiratory diseases and air pollution.