Differential requirements for interleukin (IL)-4 and IL-13 in protein contact dermatitis induced by Anisakis

IL-4Rα signalling in B cells and T cells play differential roles in acute and chronic atopic dermatitis

Atopic dermatitis (AD) is a common pruritic inflammatory skin disease with complex environmental and genetic predisposing factors. Primary skin barrier dysfunction and aberrant T helper 2 (TH2) responses to common allergens, together with increased serum IgE antibodies, characterise the disease. B and T cells are essential in the disease manifestation, however, the exact mechanism of how these cells is involved is unclear. Targeting interleukin 4 receptor alpha (IL-4Rα), an IL-4/IL-13 signalling axis, with dupilumab shows efficacy in AD. We investigated the importance of IL-4Rα signalling specifically on B and T cells during acute and chronic models of AD. We used House dust mite (HDM) and Ovalbumin (OVA) in chronic models and a low-calcemic analog of vitamin D (MC903) for acute models of AD. We used mb1creIL-4Rα-/lox, iLCKcreIL-4Rα-/lox, LCKcreIL-4Rα-/lox, CD4creIL-4Rα-/lox, Foxp3creIL-4Rα-/lox and IL-4Rα-/lox littermate controls. IL-4Rα-responsive B cells were essential in serum IgE levels, but not in epidermal thickening in both chronic and acute models. IL-4Rα-responsive T cells were essential in epidermal thickening in the pan-T cell, but not CD4 or CD8 T cells suggesting the importance of γδT cells during acute AD. Our results suggest that IL-4Rα responsiveness on innate T cells regulates acute atopic dermatitis, while on B cells it regulates IgE.

Anaphylaxis induced by Thalassophryne nattereri venom in mice is an IgE/IgG1-mediated, IL-4-dependent phenomenon

We hypothesized that beyond the Thalassophryne nattereri venoms ability to induce in mice a strong specific-Th2 response with high levels of specific IgE/IgG1, it would be able to trigger anaphylaxis in sensitized individuals. To investigate whether the venom is capable of inducing an allergic reaction in mice and characterize soluble and cellular mediators involved in this process, BALB/c female mice were sensitized intraperitoneally with decreasing-dose of venom at weekly intervals for 4 weeks and challenged by intraperitoneal, oral or epicutaneous routes with venom 2 weeks later. Our data show that sensitized-mice challenged by all routes showed intense symptoms of anaphylaxis, dependent on the anaphylactic IgG1 and IgE antibodies and mast cells. The late-phase reaction developed after initial symptoms was characterized by the influx of eosinophils, dependent on IL-5, IL-17A and eotaxin produced by Th2 cells in inflamed lungs and skin draining lymph-nodes. Using C57BL/6 deficient mice we demonstrated that IL-4 KO mice failed to develop anaphylactic symptoms or local Th2 inflammation, producing low levels of IgG1 and increased levels of IgG2a. Together our results demonstrated that the venom of T. nattereri has allergenic proteins that can trigger an allergic process, a phenomenon IgE-IgG1 dependent, IL-4-mediated and negatively regulated by IFN-γ.

Influence of Parasitic Worm Infections on Allergy Diagnosis in Sub-Saharan Africa

Epidemiological studies from Sub-Saharan Africa indicate that allergies are on the rise in this region especially in urban compared to rural areas. This increase has been linked to improved hygiene, lifestyle changes, and lower exposure to pathogens in childhood. Reduced exposure to parasitic worm (helminth) infections and allergy outcomes has been the focus of a number of population studies over the years. Paradoxically, there are parallels in the immune responses to helminths and to allergies. Both conditions are associated with elevated levels of immunoglobulin E, high numbers of T helper 2 cells, eosinophils, and mast cells. These immune parallels have meant that the diagnosis of allergies in parts of the world where helminths are endemic can be hampered. The aim of this review is to examine observations from population studies conducted in Sub-Saharan Africa that demonstrate how helminth infections influence the parameters used to diagnose allergy outcomes in this region. We explore specifically how helminth infections hinder the in vitro diagnosis of allergic sensitization, influence the clinical manifestations of allergy, and also the effect of anthelmintic treatment on allergy outcomes. Advancing our understanding of how helminths influence allergy diagnosis is imperative for the development of improved tools to assess, diagnose, and treat allergic disorders in both helminth-endemic and non-endemic countries worldwide.

Role of IL-4 receptor α-positive CD4(+) T cells in chronic airway hyperresponsiveness

BACKGROUND

TH2 cells and their cytokines are associated with allergic asthma in human subjects and with mouse models of allergic airway disease. IL-4 signaling through the IL-4 receptor α (IL-4Rα) chain on CD4(+) T cells leads to TH2 cell differentiation in vitro, implying that IL-4Rα-responsive CD4(+) T cells are critical for the induction of allergic asthma. However, mechanisms regulating acute and chronic allergen-specific TH2 responses in vivo remain incompletely understood.

OBJECTIVE

This study defines the requirements for IL-4Rα-responsive CD4(+) T cells and the IL-4Rα ligands IL-4 and IL-13 in the development of allergen-specific TH2 responses during the onset and chronic phase of experimental allergic airway disease.

METHODS

Development of acute and chronic ovalbumin (OVA)-induced allergic asthma was assessed weekly in CD4(+) T cell-specific IL-4Rα-deficient BALB/c mice (Lck(cre)IL-4Rα(-/lox)) and respective control mice in the presence or absence of IL-4 or IL-13.

RESULTS

During acute allergic airway disease, IL-4 deficiency did not prevent the onset of TH2 immune responses and OVA-induced airway hyperresponsiveness or goblet cell hyperplasia, irrespective of the presence or absence of IL-4Rα-responsive CD4(+) T cells. In contrast, deficiency of IL-13 prevented allergic asthma, irrespective of the presence or absence of IL-4Rα-responsive CD4(+) T cells. Importantly, chronic allergic inflammation and airway hyperresponsiveness were dependent on IL-4Rα-responsive CD4(+) T cells. Deficiency in IL-4Rα-responsive CD4(+) T cells resulted in increased numbers of IL-17-producing T cells and, consequently, increased airway neutrophilia.

CONCLUSION

IL-4-responsive T helper cells are dispensable for acute OVA-induced airway disease but crucial in maintaining chronic asthmatic pathology.

Genetic determinants in the development of sensitization to environmental allergens in early childhood

Sensitization to environmental allergens remains one of the strongest risk factors for asthma, and there is likely a genetic basis. We sought to identify genetic determinants for the development of allergic sensitization to environmental allergens, particularly cockroach allergen, in early childhood. A total of 631 children with the information about genotypic data on 895 single nucleotide polymorphisms (SNPs) in 179 candidate genes were selected from an existing dataset (Boston Birth Cohort). Genetic analysis was performed for allergic sensitizations among all subjects and sub-population, Black/African, respectively. Eight SNPs in seven genes showed significant association with allergic sensitization with P < 0.05, including two top SNPs, rs7851969 in JAK2 (P = 0.003) and rs11739089 in CNOT6 (P = 0.008). When analyses were specifically performed for cockroach sensitization, 16 SNPs in 13 genes showed P < 0.05, including five genes with SNPs at P < 0.01 (JAK1, JAK3, IL5RA, FCER1A, and ADAM33). Particularly, haplotype analyses demonstrated that multiple-haplotypes in FCER1A were significantly associated with cockroach sensitization with the strongest association for a 2-marker haplotype (rs6665683T-rs12136904T, P = 0.001). Furthermore, SNP rs6665683 was marginally associated with the levels of cockroach allergen specific IgE. When a similar analysis was performed for house dust mite, four SNPs in three genes (JAK2, MAML1, and NOD1) had P < 0.01. Of these, JAK2 appeared to be an only gene showing association across the sensitizations we analyzed. Some of findings were further validated when analysis was limited to black population. Our study identified several loci that may confer the susceptibility to allergic sensitization, and suggested that sensitization to allergens may depend on their unique loci.

Allergic reactions to Anisakis found in fish

The food-borne parasite Anisakis is an important hidden food allergen. Anisakis is a parasitic nematode which has a third-stage larval form that infects mainly fish, and ingestion of contaminated seafood can result in severe allergic reactions. Symptoms experienced due to exposure to this parasite include gastrointestinal disorders, urticaria, dermatitis, asthma and even anaphylaxis. Accurate prevalence data of allergic sensitisation to Anisakis are difficult to estimate due to the lack of well-designed population-based studies. Current diagnostic approaches rely on the detection of serum IgE antibodies to allergenic proteins, which however demonstrate considerable immunological cross-reactivity to other invertebrate allergens. While exposure to this parasite seems to increase due to the increasing consumption of seafood worldwide, the immunology of infection and allergic sensitization is not fully understood.

A review of parasite studies of commercially important marine fishes in sub-Saharan Africa

Scattered records of parasitic species infecting commercially important marine fishes in sub-Saharan Africa are known from just a few countries where concerted efforts have been made by local parasitologists (e.g. Senegal, Nigeria, South Africa). Most of these consist of taxonomic records or general surveys of parasite faunas associated with marine hosts, which may or may not have been of commercial value. Little to no multi-disciplinary research is conducted in most parts of sub-Saharan Africa and hence parasitological data are not commonly used to advise fisheries management procedures. This review summarizes current knowledge on all parasitological research associated with commercially important marine fish species in sub-Saharan Africa.

Foodborne anisakiasis and allergy

Human anisakiasis, a disease caused by Anisakis spp. (Nematoda), is often associated with clinical signs that are similar to those associated with bacterial or viral gastroenteritis. With the globalisation of the seafood industry, the risk of humans acquiring anisakiasis in developed countries appears to be underestimated. The importance of this disease is not only in its initial manifestation, which can often become chronic if the immune response does not eliminate the worm, but, importantly, in its subsequent sensitisation of the human patient. This sensitisation to Anisakis-derived allergens can put the patient at risk of an allergic exacerbation upon secondary exposure. This article reviews some aspects of this food-borne disease and explains its link to chronic, allergic conditions in humans.

IL-4Rα-associated antigen processing by B cells promotes immunity in Nippostrongylus brasiliensis infection

In this study, B cell function in protective T_H2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rα^−/− mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4⁺ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88^−/− B cells. These data suggest TLR dependent antigen processing by IL-4Rα-responsive B cells producing IL-13 contribute significantly to CD4⁺ T cell-mediated protective immunity against N. brasiliensis infection.

Parasitic nematode infections are an extremely important global public health problem. Infections by hookworms and roundworms for example cause anemia, widespread developmental problems and devalued immunity against bacterial infections such as salmonella and tuberculosis. Although treatable with drugs, parasitic nematode re-infections occur as humans do not develop protective immunity. Ultimately, the public health burden caused by these infections will be best controlled by the development of vaccines against nematode infections. For these to be effective, it is important to understand how the various components of the immune system can respond to infection. In this study, we show that B cells, which typically protect against infection by producing antibodies, can also protect against an experimental hookworm like nematode infection by additional mechanisms. This form of protection instead depended on B cells producing cytokines associated with parasitic nematode expulsion and also by providing T cells with specific instruction. Together, these B cell driven responses lead to a rapid resolution of the infection. These important findings indicate that vaccination strategies against nematode parasites such as hookworms need to understand immune responses other than antibody to be optimally protective.

Contact hypersensitivity models in mice

The contact hypersensitivity (CHS) reaction is commonly utilized to study cell-mediated host immune responses to epicutaneously applied allergens. This reaction is divided into two distinct phases, the afferent phase and the efferent phase. During the afferent phase of this model, mice are exposed to a contact allergen, which is typically a hapten that is applied to a location distal to the site of elicitation. Following a brief intermission, mice are reexposed to the contact allergen during the elicitation phase at a site proximal to the location of sensitization. In mice, the pinna of the ear is typically utilized to evaluate the elicitation phase. While the CHS reaction is typically utilized to study Th1-mediated immune responses, it is now evident that Th2 and Th17 cells also contribute during the elicitation phase of the model. Likewise, in humans, elevated immune responses to contact allergens are associated with a variety of atopic diseases. Here, we describe a common protocol for the induction and assessment of the CHS reaction in mice.

Occupational allergies in seafood-processing workers

Global increased demand for seafood and its products has been associated with a concomitant rise in fishing, aquaculture, and processing activities. This increased harvesting of seafood is associated with more frequent reporting of allergic health problems among seafood processors. This review outlines the high-risk working populations, work processes, as well as host and environmental exposure risk factors for occupational respiratory and skin allergies. It also provides insights into the major and minor allergens as well as the pathophysiological mechanisms implicated. Diagnostic and preventive approaches are outlined in managing work-related allergy associated with seafood processing.

A 24 kDa excretory-secretory protein of Anisakis simplex larvae could elicit allergic airway inflammation in mice

We have reported that a 24 kDa protein (22U homologous; As22U) of Anisakis simplex larvae could elicit several Th2-related chemokine gene expressions in the intestinal epithelial cell line which means that As22U may play a role as an allergen. In order to determine the contribution of As22U to allergic reactions, we treated mice with 6 times intra-nasal application of recombinant As22U (rAs22U). In the group challenged with rAs22U and ovalbumin (OVA), the number of eosinophils in the bronchial alveolar lavage fluid (BALF) was significantly increased, as compared to the group receiving only OVA. In addition, mice treated with rAs22U and OVA showed significantly increased airway hyperresponsiveness. Thus, severe inflammation around the airway and immune cell recruitment was observed in mice treated with rAs22U plus OVA. The levels of IL-4, IL-5, and IL-13 cytokines in the BALF increased significantly after treatment with rAs22U and OVA. Similarly, the levels of anti-OVA specific IgE and IgG1 increased in mice treated with rAs22U and OVA, compared to those treated only with OVA. The Gro-α (CXCL1) gene expression in mouse lung epithelial cells increased instantly after treatment with rAs22U, and allergy-specific chemokines eotaxin (CCL11) and thymus-and-activation-regulated-chemokine (CCL17) gene expressions significantly increased at 6 hr after treatment. In conclusion, rAs22U may induce airway allergic inflammation, as the result of enhanced Th2 and Th17 responses.

Cyst formation, increased anti-inflammatory cytokines and expression of chemokines support for Clonorchis sinensis infection in FVB mice

To verify the hypothesis that different pathology of Clonorchis sinensis infection by mouse strains is determined by different responses of cytokines and chemokines, we compared those responses of FVB with those of BALB/c mice. All of FVB mice infected with 30 metacercariae of C. sinensis showed cystic dilatation in the liver, whereas infected BALB/c mice did not. Mature worms were recovered from 19 of 20 liver sections of FVB mice while only one of 20 sections of BALB/c mice revealed a mature worm. In both strains the proportion of CD4(+) T cells was lower in C. sinensis-infected than in the uninfected group. However, the proportion of CD8(+) T cells was elevated in C. sinensis-infected from both strains compared to uninfected mice. The Th2-associated anti-inflammatory cytokines such as IL-4, IL-5 and IL-13, IL-10 and TGF-β, were significantly more produced by the lymphocytes of FVB than by those of BALB/c mice. Especially, the 2 anti-inflammatory cytokines, IL-10 and TGF-β, were presumably related with susceptibility and the development of worms in the liver. C. sinensis infected FVB mice also produced more chemokines such as RANTES and MIP-1α in the liver lymphocytes than BALB/c mice. In conclusion, the FVB mice provide the favorable niche for C. sinensis by cyst formation in the bile duct, increased production of Th2-associated anti-inflammatory cytokines and upregulation of chemokines.

Anisakis pegreffii-induced airway hyperresponsiveness is mediated by gamma interferon in the absence of interleukin-4 receptor alpha responsiveness

Infection with the fish parasite Anisakis following exposure to contaminated fish can lead to allergic reactions in humans. The present study examined the immunological mechanisms underlying the development of allergic airway inflammation in mice after different routes of sensitization to Anisakis. Wild-type and interleukin-4 receptor alpha (IL-4Ralpha)-deficient BALB/c mice were sensitized intraperitoneally with live or heat-killed Anisakis larvae or by intranasal administration of an Anisakis extract and were subsequently challenged intranasally with an Anisakis extract. Both routes of sensitization induced IL-4Ralpha-dependent allergic airway responses, whereas allergen-specific antibody responses developed only when mice were sensitized intraperitoneally. Intranasal sensitization induced airway hyperresponsiveness (AHR) in wild-type mice only, showing that AHR was IL-4/IL-13 dependent. Unexpectedly, infection with Anisakis larvae induced AHR in both wild-type and IL-4Ralpha-deficient mice. IL-4Ralpha-independent AHR was mediated by gamma interferon (IFN-gamma), as evidenced by the fact that in vivo neutralization of IFN-gamma abrogated AHR. Together, these results demonstrate that both infection with larvae and inhalational exposure to Anisakis proteins are potent routes of allergic sensitization to Anisakis, explaining food- and work-related allergies in humans. Importantly for diagnosis, allergic airway inflammation can be independent of detectable Anisakis-specific antibodies. Moreover, depending on the route of sensitization, AHR can be induced either by IL-4/IL-13 or by IFN-gamma.