Acanthamoeba profilin elicits allergic airway inflammation in mice

Background

In previous studies, we suggested that Acanthamoeba is a new aero-allergen and that patients who showed positive results for the skin-prick test response to Acanthamoeba cross-reacted with several pollen allergens. Additionally, patients with common antibodies reacted to the 13–15 kDa Acanthamoeba unknown allergen.

Objective

We examined whether profilin of Acanthamoeba is a human airway allergic agent because of its molecular weight.

Methods

We expressed recombinant Ac-PF (rAc-PF) protein using an Escherichia coli expression system and evaluated whether Ac-PF is an airway allergic agent using an allergic airway inflammation animal model.

Results

Airway hyperresponsiveness was increased in rAc-PF-inoculated mice. The number of eosinophils and levels of Th2 cytokines, interleukin (IL)-4, IL-5, and IL-13 were increased in the bronchial alveolar lavage fluid of rAc-PF-treated mice. The lungs of the rAc-PF-treated mice group showed enhanced mucin production and metaplasia of lung epithelial cells and goblet cells.

Conclusion

In this study, we demonstrated that rAc-PF may be an allergen in Acanthamoeba, but further studies needed to identify the mechanisms of allergenic reactions induced by Ac-PF.

Recently, the number of asthma patients have increased sharply. Among patients with asthma have a high serum IgE titer, but despite this, some of these patients do not react to known allergens in skin prick tests, that suggests the presence of unknown environmental allergens. The protozoa Acanthamoeba live in very diverse environment including water, soil, air and even human nasal cavities, throat, pharynx and lung. In previous study, Acanthamoeba could be a new aero-allergen. Patients who showed positive results for the skin-prick test response to Acanthamoeba, their serum could be cross-reacted with several pollen allergens as well as Acanthamoeba total proteins. Additionally, the patients have common antibodies reacted to the 13–15 kDa Acanthamoeba unknown allergen. Profilin, which is found in all eukaryotic organisms in most cells, is an actin-binding protein that interferes with nucleation and restructuring of new filaments. Recent studies showed that profilin functions as a pan-allergen recognized by IgE in approximately 20% of birch pollen and plant food allergic patients. In Acanthamoeba, two isoforms of profilin (Ac-PF) have been identified: profilin-I and profilin-II. We examined profilin from Acanthamoeba as a potential human airway allergic agent because of its molecular weight (13–14 kDa) and cross-reactivity with several pollen allergens in the skin prick test showing positive results for Acanthamoeba in chronic cough patients. In this study, we expressed recombinant Ac-PF (rAc-PF) protein using an Escherichia coli expression system and evaluated whether Ac-PF is an airway allergic agent using an asthma animal model. Our study showed that rAc-PF may be an allergen in Acanthamoeba, but further studies needed to identify the mechanisms of allergenic reactions induced by Ac-PF.

Schistosoma japonicum infection downregulates house dust mite-induced allergic airway inflammation in mice

The “hygiene hypothesis” is a theory try to explain the dramatic increases in the prevalence of autoimmune and allergic diseases over the past two to three decades in developed countries. According to this theory, reduced exposure to parasites and microorganisms in childhood is the main cause for the increased incidences of both T helper 1 (Th1)-mediated autoimmunity and Th2-mediated allergy. In this study, we investigated the impact of Schistosoma japonicum infection on the allergic airway inflammation induced by repeated intracheal inoculations of house dust mites (HDM), which is a Th17 and neutrophils dominant murine asthma model, mimicking severe asthma. We found that S. japonicum infection downregulated airway hyperresponsiveness. The infiltrating cells, Th17 and Th2 effector cytokines in the bronchoalveolar lavage (BAL) fluids and lungs were significantly reduced in the infected mice. Our findings indicated that S. japonicum infection was able to effectively inhibit host’s allergic airway inflammation, which may be related to the upregulated Treg cells upon infection. To our knowledge, it is the first study to reveal the impact of S. japonicum infection on house dust mite induced severe asthma. More in depth investigation is need to elucidate the underlying mechanisms.

Acanthamoeba protease activity promotes allergic airway inflammation via protease-activated receptor 2

Acanthamoeba is a free-living amoeba commonly present in the environment and often found in human airway cavities. Acanthamoeba possesses strong proteases that can elicit allergic airway inflammation. To our knowledge, the aeroallergenicity of Acanthamoeba has not been reported. We repeatedly inoculated mice with Acanthamoeba trophozoites or excretory-secretory (ES) proteins intra-nasally and evaluated symptoms and airway immune responses. Acanthamoeba trophozoites or ES proteins elicited immune responses in mice that resembled allergic airway inflammation. ES proteins had strong protease activity and activated the expression of several chemokine genes (CCL11, CCL17, CCL22, TSLP, and IL-25) in mouse lung epithelial cells. The serine protease inhibitor phenyl-methane-sulfonyl fluoride (PMSF) inhibited ES protein activity. ES proteins also stimulated dendritic cells and enhanced the differentiation of naive T cells into IL-4-secreting T cells. After repeated inoculation of the protease-activated receptor 2 knockout mouse with ES proteins, airway inflammation and Th2 immune responses were markedly reduced, but not to basal levels. Furthermore, asthma patients had higher Acanthamoeba-specific IgE titers than healthy controls and we found Acanthamoeba specific antigen from house dust in typical living room. Our findings suggest that Acanthamoeba elicits allergic airway symptoms in mice via a protease allergen. In addition, it is possible that Acanthamoeba may be one of the triggers human airway allergic disease.

Prevention of house dust mite induced allergic airways disease in mice through immune tolerance

Allergic airways disease is a consequence of a Th2 response to an allergen leading to a series of manifestations such as production of allergen-specific IgE, inflammatory infiltrates in the airways, and airway hyper-reactivity (AHR). Several strategies have been reported for tolerance induction to allergens leading to protection from allergic airways disease. We now show that CD4 blockade at the time of house dust mite sensitization induces antigen-specific tolerance in mice. Tolerance induction is robust enough to be effective in pre-sensitized animals, even in those where AHR was pre-established. Tolerant mice are protected from airways eosinophilia, Th2 lung infiltration, and AHR. Furthermore, anti-CD4 treated mice remain immune competent to mount immune responses, including Th2, to unrelated antigens. Our findings, therefore, describe a strategy for tolerance induction potentially applicable to other immunogenic proteins besides allergens.

IL-13 induces disease-promoting type 2 cytokines, alternatively activated macrophages and allergic inflammation during pulmonary infection of mice with Cryptococcus neoformans

In the murine model of Cryptococcus neoformans infection Th1 (IL-12/IFN-gamma) and Th17 (IL-23/IL-17) responses are associated with protection, whereas an IL-4-dependent Th2 response exacerbates disease. To investigate the role of the Th2 cytokine IL-13 during pulmonary infection with C. neoformans, IL-13-overexpressing transgenic (IL-13Tg(+)), IL-13-deficient (IL-13(-/-)), and wild-type (WT) mice were infected intranasally. Susceptibility to C. neoformans infection was found when IL-13 was induced in WT mice or overproduced in IL-13Tg(+) mice. Infected IL-13Tg(+) mice had a reduced survival time and higher pulmonary fungal load as compared with WT mice. In contrast, infected IL-13(-/-) mice were resistant and 89% of these mice survived the entire period of the experiment. Ag-specific production of IL-13 by susceptible WT and IL-13Tg(+) mice was associated with a significant type 2 cytokine shift but only minor changes in IFN-gamma production. Consistent with enhanced type 2 cytokine production, high levels of serum IgE and low ratios of serum IgG2a/IgG1 were detected in susceptible WT and IL-13Tg(+) mice. Interestingly, expression of IL-13 by susceptible WT and IL-13Tg(+) mice was associated with reduced IL-17 production. IL-13 was found to induce formation of alternatively activated macrophages expressing arginase-1, macrophage mannose receptor (CD206), and YM1. In addition, IL-13 production led to lung eosinophilia, goblet cell metaplasia and elevated mucus production, and enhanced airway hyperreactivity. This indicates that IL-13 contributes to fatal allergic inflammation during C. neoformans infection.

[Argas reflexus (Fabricius, 1794) as a cause of acarosis in people]

The studies were carried out between 1997-1999 within the administrative district of Toruń. Forty sports pigeon breeders together with their pigeonswere understudy annually. The collected material allowed noticing the following issues: in 1997 and 1998 the Argas reflexus (Fabricius, 1794) was present in dovecotes (individuals) and t he breeds' owners were pricked. In 1998 numerous specimens of the A. reflexus were obtained from the material from the sanitary-epidemiological station. The specimens were collected from the bodies of the people, family members and from their flat located on the highest third floor of the old house. In the mite-infected dovecotes and in the old houserooms, the following steps were suggested: mechanical cleansing, whitewashing, disinfecting, and triple disinsecting, with fourteen-day-long intervals. The people with the symptoms of acariosis were subjected to treatment with calcium, anti-allergic, and anti-fever mixtures, and, in some cases, cortisone ointments were applied. In spite of a considerable growth in the symptoms, the used methods turned out to be successful in all the studied cases.

Exposure to foodborne and orofecal microbes versus airborne viruses in relation to atopy and allergic asthma: epidemiological study

OBJECTIVE

To investigate if markers of exposure to foodborne and orofecal microbes versus airborne viruses are associated with atopy and respiratory allergies.

DESIGN

Retrospective case-control study.

PARTICIPANTS

240 atopic cases and 240 non-atopic controls from a population sample of 1659 participants, all Italian male cadets aged 17-24.

SETTING

Air force school in Caserta, Italy.

MAIN OUTCOME MEASURES

Serology for Toxoplasma gondii, Helicobacter pylori, hepatitis A virus, measles, mumps, rubella, chickenpox, cytomegalovirus, and herpes simplex virus type 1; skin sensitisation and IgE antibodies to relevant airborne allergens; total IgE concentration; and diagnosis of allergic asthma or rhinitis.

RESULTS

Compared with controls there was a lower prevalence of T gondii (26% v 18%, P=0.027), hepatitis A virus (30% v 16%, P=0.004), and H pylori (18% v 15%, P=0.325) in atopic participants. Adjusted odds ratios of atopy decreased with a gradient of exposure to H pylori, T gondii, and hepatitis A virus (none, odds ratio 1; one, 0. 70; two or three, 0.37; P for trend=0.000045) but not with cumulative exposure to the other viruses. Conversely, total IgE concentration was not independently associated with any infection. Allergic asthma was rare (1/245, 0.4%) and allergic rhinitis infrequent (16/245, 7%) among the participants (245/1659) exposed to at least two orofecal and foodborne infections (H pylori, T gondii, hepatitis A virus).

CONCLUSION

Respiratory allergy is less frequent in people heavily exposed to orofecal and foodborne microbes. Hygiene and a westernised, semisterile diet may facilitate atopy by influencing the overall pattern of commensals and pathogens that stimulate the gut associated lymphoid tissue thus contributing to the epidemic of allergic asthma and rhinitis in developed countries.

Spider mite allergy in apple-cultivating farmers: European red mite (Panonychus ulmi) and two-spotted spider mite (Tetranychus urticae) may be important allergens in the development of work-related asthma and rhinitis symptoms

BACKGROUND

Recent investigations have suggested that the citrus red mite (Panonychus citri) is the most important allergen affecting citrus-cultivating farmers with asthma, allergic rhinitis, or both.

OBJECTIVE

We sought to evaluate type I hypersensitivity to spider mites, particularly the European red mite (Panonychus ulmi) and the two-spotted spider mite (Tetranychus urticae), and to determine the relationship between hypersensitivity to spider mites and respiratory dysfunction.

METHODS

We performed a cross-sectional survey. Questionnaires were given, and skin prick tests for 11 inhalant allergens common in Korea and 2 species of spider mites (European red mite and two-spotted spider mite) were performed in 725 apple-cultivating farmers in Korea.

RESULTS

Results of skin prick tests in the apple farmers indicated that European red mite (23.2%) was the most common sensitizing allergen, followed by Tyrophagus putrescentiae (21.2%), two-spotted spider mite (16.6%), Dermatophagoides farinae (16.3%), D pteronyssinus (14.4%), cockroach (13.1%), and Hop Japanese (Humulus Japonicus) pollen (12.0%). Positive skin responses (mean wheal size >/=3 mm) to one or more of 13 inhalant allergens were found in 48.2% of farmers tested, whereas 40 subjects (8.6%) had an isolated skin response to the spider mites. Among 119 farmers with work-related asthmatic symptoms, the positive skin response rates to European red mite and two-spotted spider mite were 40.4% and 27.0%, respectively. These figures were significantly higher than those found among farmers without work-related symptoms (19.1% and 14.1%, respectively; P <.01). The prevalence of work-related asthma symptoms was higher in farmers with positive skin responses to spider mites than in those with negative skin responses to spider mites and those with positive skin responses to any allergen tested (31.4% vs 15.0% vs 21.0%, respectively; P <.05).

CONCLUSION

Spider mites, particularly European red mite and 2-spotted spider mite, are common sensitizing allergens in apple-cultivating farmers. These spider mites may be important causative allergens in the development of work-related respiratory symptoms in these workers.

Association between giardiasis and allergy

BACKGROUND

Previous studies have indicated that there may be an association between infection by the intestinal protozoan Giardia lamblia and the expression of allergic disease.

OBJECT

We evaluated a group of children who attended the Outpatient Clinic of the Children's Hospital in Caracas, Venezuela, a group in which both allergic disease and giardiasis were common.

METHODS

We performed feces examination and measured total and specific serum IgE (immunoglobulin E) in these children.

RESULTS

We found that 70% of the children infected with G. lamblia presented symptoms of allergy, in contrast to 43% of the non-Giardia parasitized group (P <.05). In addition, the G. lamblia parasitized children showed significantly higher levels of total serum IgE (1194 IU/mL) than the non-Giardia group (822 IU/mL) (P <.005). Children infected with G. lamblia showed higher levels of specific serum IgE antibody against food allergens compared both with the non-parasitized group (P <.0001) and children infected with parasites other than Giardia (P <.05). In contrast, IgE responses against the house dust mite Dermatophagoides pteronyssinus were similar in all the groups studied.

CONCLUSIONS

These results reveal a clear relationship between giardiasis and allergy, possibly because infection by this protozoon enhances sensitization towards food antigens, due to increased antigen penetration through damaged intestinal mucosa.

Relationship between allergic manifestations and Toxocara seropositivity: a cross-sectional study among elementary school children

Toxocara (the cause of visceral larva migrans in humans) and allergy have in common both elevated immunoglobulin E (IgE) levels and eosinophilia. In the present study, we investigated: 1) associations between Toxocara seropositivity and allergic manifestations; 2) risk factors for Toxocara infection; and 3) differences in Toxocara seroprevalence, allergic manifestations and the associations between these two, in children from urban and rural environments. Blood samples from 1,379 Dutch urban and rural elementary schoolchildren, were examined for Toxocara antibodies, eosinophil numbers, total IgE concentrations, and the occurrence of inhaled allergen-specific IgE. Questionnaires investigating respiratory health and putative risk factors for infection were completed. It was found that 8% of the children had Toxocara antibodies, occurring significantly less often in females than in males. The means of total serum IgE levels and blood eosinophils were significantly higher in the Toxocara-seropositive than in the seronegative group. Allergic asthma/recurrent bronchitis was found in 7% of the children, allergic reaction on animal contact in 4%, and IgE to at least one inhaled allergen in 16%. These variables were associated with Toxocara seroprevalence. Inhaled allergen-specific IgE and asthma/recurrent bronchitis occurred significantly less often in rural than in urban areas, and significantly less often among girls than among boys. Furthermore, occurrence of allergen-specific IgE increased significantly with age. No association existed between Toxocara seroprevalence and assumed risks, i.e. contact with pet animals and public playgrounds. In conclusion, our results indicate that allergic manifestations occur more often in Toxocara-seropositive children. A relationship with an already existing allergic condition is plausible.

The Marrara syndrome: a hypersensitivity reaction of the upper respiratory tract and buccopharyngeal mucosa to nymphs of Linguatula serrata

The Marrara syndrome, like Halazoun in Lebanon, is a hypersensitivity reaction of the upper respiratory tract and buccopharyngeal mucosa to nymphs of Linguatula serrata. The condition follows the consumption of Marrara which consists of raw liver, lungs, trachea and rumen of goats and sheep infected with larvae of L. serrata. The adult worm is found in the nasal passages of dogs. Sheep and goats are infected by eggs from infected dogs. A survey that included 240 adult individuals in a village of endemic L. serrata infection in the Sudan showed that 20% experienced symptoms of allergic nasopharyngitis (Marrara syndrome) following the consumption of raw viscera of goats or sheep at least once in their life. In a prospective study of 24 patients who reported to hospital with the Marrara syndrome, the clinical features included itching in the throat and nose, unilateral conductive deafness, tinnitus and facial palsy. Secondary bacterial infection caused suppurative otitis media. Adult L. serrata parasites were found in the nasal passages of 56 and 47% of male and female dogs in the endemic area. Nymphs were recovered from the mesenteric lymph nodes, lungs and livers of goats in the area.