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

Natural killer T cells in allergic asthma: implications for the development of novel immunotherapeutical strategies

Allergic asthma has emerged as a prevalent allergic disease worldwide, affecting most prominently both young individuals and lower-income populations in developing and developed countries. To devise effective and curative immunotherapy, it is crucial to comprehend the intricate nature of this condition, characterized by an immune response imbalance that favors a proinflammatory profile orchestrated by diverse subsets of immune cells. Although the involvement of Natural Killer T (NKT) cells in asthma pathology is frequently implied, their specific contributions to disease onset and progression remain incompletely understood. Given their remarkable ability to modulate the immune response through the rapid secretion of various cytokines, NKT cells represent a promising target for the development of effective immunotherapy against allergic asthma. This review provides a comprehensive summary of the current understanding of NKT cells in the context of allergic asthma, along with novel therapeutic approaches that leverage the functional response of these cells.

Purified Native and Recombinant Major Alternaria alternata Allergen (Alt a 1) Induces Allergic Asthma in the Murine Model

Aeroallergens such us the spores of Alternaria alternata are described as the most important agents associated with respiratory allergies and severe asthma. Various experimental models of asthma have been developed using A. alternata extracts to study the pathogenesis of asthma, establishing the main parameters that trigger the asthmatic response. In this study, we describe a mouse model of asthma induced only by Alt a 1. To induce the allergic response, mice were challenged intranasally with the major allergen of A. alternata, Alt a 1. The presence of eosinophils in the lungs, elevated concentrations of Th2 family cytokines, lymphocyte proliferation and elevated IgE total serum levels indicated that the sensitisation and challenge with Alt a 1 induced the development of airway inflammation. Histological studies showed an eosinophilic cellular infiltrate in the lung tissue of mice instilled with Alt a 1. We demonstrate that Alt a 1 alone is capable of inducing a lung inflammatory response with an increase in IgE serum levels mimicking the allergic asthma immunoresponse when it is administered into BALB/c mice. This model will allow the evaluation of the immunoregulatory or immunotolerant capacity of several molecules that can be used in targeted immunotherapy for fungal allergic asthma.

Immunoprotective inference of experimental chronic Trichinella spiralis infection on house dust mites induced allergic airway remodeling

Allergic bronchial asthma is characterized by chronic inflammation of the respiratory airways mediated by T-helper 2 (Th2), Th17 and their cytokines. Although most asthmatic patients suffer from allergic airway remodeling (AAR), aggressive anti-allergic treatment failed to reverse it. The hygiene hypothesis illuminated the counter relationship between allergy and helminthic infections. The immune system is modulated by Trichinella spiralis (T. spiralis) infection to maintain homeostasis. Therefore, this work aimed to investigate the impact of chronic T. spiralis infection on induced AAR in C57BL/6 mice sensitized by house dust mites (HDM) allergens. Forty mice were divided into 3 groups: I (10 healthy mice), IΙ (15 HDM sensitized mice), and ΙΙI (15 T. spiralis chronically infected mice and sensitized with HDM allergens). The assessment aimed to evaluate the effects of regulatory CD4+CD25+FOXP3+ cells (Tregs) and their cytokines comparative to hypersensitivity mediated cytokines. Chronic T. spiralis infection effectively prevented the host's AAR. This result was evidenced by upregulated Tregs in blood by flow cytometric analysis and increased interleukin-10 (IL-10) levels in bronchoalveolar lavage (BAL) by Enzyme linked immunosorbent assay (ELISA) as well as improved lung histopathological changes. Also, serum HDM specific immunoglobulin E (IgE), BAL eosinophils, BAL IL-5 levels, and IL-17 gene expression in lung tissues were significantly reduced in T. spiralis chronically infected mice. In conclusion, the immune response in chronic T. spiralis infection could provide a promising mechanistic tool for protection against AAR, which paves the way for innovative preventive measures of other immunological disorders.

Skin Exposure Contributes to Chemical-Induced Asthma: What is the Evidence? A Systematic Review of Animal Models

It is generally assumed that allergic asthma originates primarily through sensitization via the respiratory mucosa, but emerging clinical observations and experimental studies indicate that skin exposure to low molecular weight (LMW) agents, i.e. “chemicals,” may lead to systemic sensitization and subsequently develop asthma when the chemical is inhaled. This review aims to evaluate the accumulating experimental evidence that adverse respiratory responses can be elicited upon inhalation of an LMW chemical sensitizer after previous sensitization by dermal exposure. We systematically searched the PubMed and Embase databases up to April 15, 2017, and conducted forward and backward reference tracking. Animal studies involving both skin and airway exposure to LMW agents were included. We extracted 6 indicators of “selective airway hyper-responsiveness” (SAHR)—i.e. respiratory responses that only occurred in previously sensitized animals—and synthesized the evidence level for each indicator into strong, moderate or limited strength. The summarized evidence weight for each chemical agent was graded into high, middle, low or “not possible to assess.” We identified 144 relevant animal studies. These studies involved 29 LMW agents, with 107 (74%) studies investigating the occurrence of SAHR. Indicators of SAHR included physiological, cytological/histological and immunological responses in bronchoalveolar lavage, lung tissue and airway-draining lymph nodes. Evidence for skin exposure-induced SAHR was present for 22 agents; for 7 agents the evidence for SAHR was inconclusive, but could not be excluded. The ability of a chemical to cause sensitization via skin exposure should be regarded as constituting a risk of adverse respiratory reactions.

Diphteria-tetanus-pertussis vaccine reduces specific IgE, inflammation and remodelling in an animal model of mite-induced respiratory allergy

BACKGROUND

Adjuvants, such as bacterial lipopolysaccharides, have been studied to improve the efficacy of allergen-specific immunotherapy. The Bordetella pertussis (Pw) vaccine has been shown to have a protective role in ovalbumin-induced asthma models. However, its role in allergy to mites is unknown. We evaluated the effects of the diphtheria-tetanus-pertussis (DTPw) vaccine on a murine model of respiratory allergy induced by Dermatophagoides pteronyssinus (Derp).

METHODS

In a 30-day protocol, BALB/c mice were immunized subcutaneously with saline or Derp, alone or in combination with diphtheria-tetanus (DT) or DTPw vaccines (days 0, 7 and 14). Subsequently, they underwent a daily intranasal challenge with saline or Derp (days 22-28) and were then sacrificed (day 29). We evaluated serum-specific immunoglobulins, bronchoalveolar lavage (BAL) cellularity, remodelling of the lower airways, density of polymorphonuclear leukocytes (PMNs) and acidic nasal mucus content.

RESULTS

The animals sensitized with Derp produced high levels of specific immunoglobulins, increased density of PMNs and nasal mucus content, and elevated BAL cellularity and remodelling. Vaccines led to a reduction in IgE levels, with the Derp-DTPw group being similar to the saline groups. The vaccinated groups had reductions of BAL cellularity and remodelling, with more expressive results in the Derp-DTPw group compared to the Derp-DT group. The DT and DTPw vaccines inhibited the nasal PMN infiltrate, and DTPw modulated the production of acidic nasal mucus.

CONCLUSIONS

The DTPw vaccine reduced serum specific IgE, nasal and pulmonary inflammation and remodelling of the lower airways.

Animal models of asthma: utility and limitations

Clinical studies in asthma are not able to clear up all aspects of disease pathophysiology. Animal models have been developed to better understand these mechanisms and to evaluate both safety and efficacy of therapies before starting clinical trials. Several species of animals have been used in experimental models of asthma, such as Drosophila, rats, guinea pigs, cats, dogs, pigs, primates and equines. However, the most common species studied in the last two decades is mice, particularly BALB/c. Animal models of asthma try to mimic the pathophysiology of human disease. They classically include two phases: sensitization and challenge. Sensitization is traditionally performed by intraperitoneal and subcutaneous routes, but intranasal instillation of allergens has been increasingly used because human asthma is induced by inhalation of allergens. Challenges with allergens are performed through aerosol, intranasal or intratracheal instillation. However, few studies have compared different routes of sensitization and challenge. The causative allergen is another important issue in developing a good animal model. Despite being more traditional and leading to intense inflammation, ovalbumin has been replaced by aeroallergens, such as house dust mites, to use the allergens that cause human disease. Finally, researchers should define outcomes to be evaluated, such as serum-specific antibodies, airway hyperresponsiveness, inflammation and remodeling. The present review analyzes the animal models of asthma, assessing differences between species, allergens and routes of allergen administration.

Association between KIR genes and dust mite sensitization in a Brazilian population

BACKGROUND

Killer cell immunoglobulin-like receptors (KIRs), found on the surface of natural killer (NK) cells, play a key role in controlling the innate response. Such response depends on a series of cellular interactions between these receptors and HLA activating/inhibiting ligands. Atopic diseases have been associated with genes that regulate cytokine production and HLA genes, which may either protect or predispose to hypersensitivity.

OBJECTIVE

To verify an association study of KIR genes with sensitization to the following mites: Dermatophagoides farinae, Dermatophagoides pteronyssinus, and Blomia tropicalis.

METHODS

A total of 341 children aged up to 14 years, were classified as mite-sensitive or mite-insensitive after undergoing a skin prick test for immediate allergic reactions. The presence/absence of KIR genes and their human leukocyte antigen (HLA) ligands was determined by polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) with the commercial kit LabType™ using Luminex™.

RESULTS

The frequencies of KIR genes and their respective class I HLA ligands and the frequency of haplotypes were performed in sensitive and insensitive individuals, and no significant differences were found.

CONCLUSION

Our results suggest no influence of KIR genes on resistance/susceptibility to sensitization to dust mites.