Regulatory role of B cells in a murine model of allergic airway disease

Mice sensitized to OVA and subjected to acute OVA aerosol exposures develop allergic airway disease (AAD). However, chronic continuous Ag exposure results in resolution of AAD and the development of local inhalational tolerance (LIT). Because we have previously observed the persistence of B cells in the bronchoalveolar lavage (BAL) and hilar lymph nodes (HLN) at the resolution stage of this model, we investigated the role of B cells in the modulation of AAD. Although B cell-deficient mice developed LIT, adoptive transfer of HLN B cells from LIT mice to OVA-sensitized recipients resulted in attenuated AAD following subsequent OVA aerosol exposure, as determined by reduced BAL leukocytosis and eosinophilia, decreased tissue inflammation, and absent methacholine hyper-responsiveness. In similar adoptive transfer studies, HLN B cells from AAD mice were without effect. The protection transferred by LIT HLN B cells was Ag specific and was associated with accumulation of Foxp3(+) T regulatory cells regionally in BAL and HLN, but not systemically in the spleen. Fluorescent labeling of LIT HLN B cells before adoptive transfer demonstrated that these cells had the capacity to migrate to local inflammatory sites. In vitro assessment demonstrated that the LIT HLN B cells exerted this regulatory effect via TGF-beta induced conversion of CD4(+)CD25(-) T effector cells into functionally suppressive CD4(+)CD25(+)Foxp3(+) T regulatory cells. These findings illustrated a novel regulatory role for regional B cells in AAD and suggested a possible contributory role of B cells, along with other cell types, in the establishment of LIT.     

Interleukin-10 does not mediate inhalational tolerance in a chronic model of ovalbumin-induced allergic airway disease

OBJECTIVE: IL-10 is a potent anti-inflammatory cytokine, and IL-10-producing regulatory T cells are effective inhibitors of murine asthmatic responses. This study determined whether IL-10-dependent mechanisms mediated the local inhalational tolerance seen with chronic inhalational exposure to antigen. METHODS: Wildtype and IL-10(-/-) mice were sensitized with ovalbumin (OVA) and then challenged with daily OVA inhalations for 10 days or 6 weeks. RESULTS: The 10-day animals developed allergic airway disease, characterized by BAL eosinophilia, histologic airway inflammation and mucus secretion, methacholine hyperresponsiveness, and OVA-specific IgE production. These changes were more pronounced in IL-10(-/-) mice. The 6-week IL-10(-/-) and wildtype animals both developed inhalational tolerance, with resolution of airway inflammation but persistence of OVA-specific IgE production. CONCLUSION: IL-10 may have anti-inflammatory effects in the acute stage of murine allergic airways disease, but the cytokine does not mediate the development of local inhalational tolerance with chronic antigen exposure.     

Regulation of IgE activity in inhalational tolerance via formation of IgG anti-IgE/IgE immune complexes

Background

Allergic asthma is an inflammatory disorder of the airways that results from inappropriate production of IgE against harmless, environmental antigens. Sequestration of free IgE using humanized IgG anti-IgE is an effective therapy for asthma and other atopic disorders. However, the status of free IgE in subjects who have naturally developed immune tolerance to inhaled antigens has not been well studied.

Methods

C57BL/6 mice were sensitized and challenged with ovalbumin (OVA) for 7 days to induce allergic airway disease (AAD) or 6 weeks to induce a state of local inhalational tolerance (LIT). Serum from AAD or LIT mice, diluted to achieve equivalent levels of total OVA-specific IgE, was used to sensitize rat basophil leukemia cells for allergen-mediated degranulation. Levels of degranulation were measured in relation to serum concentrations of free IgE and IgG anti-IgE/IgE immune complexes.

Results

Serum from AAD animals induced a greater degree of basophil degranulation than serum from LIT animals. These results correlated with higher levels of free IgE in AAD animals, whereas LIT mice demonstrated a significant increase in IgG anti-IgE/IgE immune complexes relative to their diseased counterparts.

Conclusions

Sequestration of free IgE by naturally occurring IgG anti-IgE may aid in the development of immune tolerance against inhaled allergens. The decrease in bioavailability of free IgE may, in turn, contribute to the overall reduction of asthma symptoms via a mechanism that mimics the therapeutic effects of humanized IgG anti-IgE.

     

Temporal correlation of measurements of airway hyperresponsiveness in ovalbumin-sensitized mice

Airway hyperresponsiveness, airway inflammation, and reversible airway obstruction are physiological hallmarks of asthma. These responses are increasingly being studied in murine models of antigen exposure and challenge, using whole body plethysmography to noninvasively assess airway hyperresponsiveness. This approach infrequently has been correlated with indexes of airway hyperresponsiveness measured by invasive means. Furthermore, correlation with quantitative histological data for tissue infiltration by inflammatory and immune cells, particularly in the wall of airways, during daily airway challenge is lacking. To address these uncertainties, we used C57BL/6 mice that were immunized with ovalbumin or vehicle (saline) and sensitized to aerosolized ovalbumin or vehicle 8 days later. The mice were subsequently exposed to aerosolized ovalbumin or vehicle, respectively, on days 14-22. We assessed airway hyperresponsiveness to methacholine noninvasively on days 14, 15, 18, or 22; we studied the same mice 24 h later while they were anesthetized for invasive analyses of airway hyperresponsiveness. Plasma total IgE concentration was significantly higher in the ovalbumin-treated mice compared with the vehicle-treated mice, but this did not correlate with eosinophil number. Peak airway hyperresponsiveness measured by either approach correlated early during daily antigen challenge (days 14 and 15), but this correlation was lost later during subsequent daily antigen challenges (days 18 and 22). On days 14 and 15, peak airway hyperresponsiveness correlated with transmigration of neutrophils and macrophages, but not lymphocytes, in the peribronchovascular connective tissue sheaths. This extravascular accumulation was found to be focal by three-dimensional microscopy. We conclude that, although ovalbumin treatment changed lung function in mice, correlation between noninvasive and invasive measures of peak airway hyperresponsiveness was inconsistent.     

Tolerance induced by chronic inhaled antigen in a murine asthma model is not mediated by endotoxin

Ovalbumin (OVA)-sensitized wildtype (WT) and endotoxin-resistant (ER) mice developed similar degrees of airways eosinophilia and serum OVA-specific IgE levels after acute aerosolized OVA challenge. WT mice demonstrated methacholine hyperreactivity, whereas ER mice showed no change in responsiveness. With chronic aerosolized OVA challenge, both WT and ER mice developed local tolerance, with resolution of airway eosinophilia but persistence of anti-OVA IgE in serum. Thus, the development of local tolerance with chronic aerosol exposure to OVA is independent of any potential effects of endotoxin in the OVA aerosol solution.     

Mucosal immunotherapy with CpG oligodeoxynucleotides reverses a murine model of chronic asthma induced by repeated antigen exposure

Murine models of acute atopic asthma may be inadequate to study the effects of recurrent exposure to inhaled allergens, such as the epithelial changes seen in asthmatic patients. We developed a murine model in which chronic airway inflammation is maintained by repeated allergen [ovalbumin (OVA)] inhalation; using this model, we examined the response to mucosal administration of CpG DNA (oligonucleotides) and specific antigen immunotherapy. Mice repeatedly exposed to OVA developed significantly greater airway hyperresponsiveness and goblet cell hyperplasia, but not airway eosinophilia, compared with those exposed only twice. CpG-based immunotherapy significantly reversed both acute and chronic markers of inflammation as well as airway hyperresponsiveness. We further examined the effect of mucosal immunotherapy on the response to a second, unrelated antigen. Mice sensitized to both OVA and schistosome eggs, challenged with inhaled OVA, and then treated with OVA-directed immunotherapy demonstrated significant reduction of airway hyperresponsiveness and a moderate reduction in eosinophilia, after inhalation challenge with schistosome egg antigens. In this model, immunotherapy treatment reduced bronchoalveolar lavage (BAL) levels of Th2 cytokines (IL-4, IL-5, IL-13, and IL-10) without changing BAL IFN-gamma. Antigen recall responses of splenocytes from these mice demonstrated an antigen-specific (OVA) enhanced release of IL-10 from splenocytes of treated mice. These results suggest that CpG DNA may provide the basis for a novel form of immunotherapy of allergic asthma. Both antigen-specific and, to a lesser extent, antigen-nonspecific responses to mucosal administration of CpG DNA are seen.     

Effect of orally administered non-viable Lactobacillus cells on murine humoral immune responses

BALB/c mice were immunized intraperitoneally with the food antigen ovalbumin (OVA) while they were fed with Lactobacillus GG heated killed cell preparation. The oral administration of Lactobacillus GG did not appear to modify the antigen-augmented serum IgE in the tested mice but significantly augmented serum OVA specific IgG in the tested mice fed with a diet containing 0.1% Lactobacillus GG as the non-viable cell preparation (P< 0.05). The fecal OVA specific IgA of the tested mice fed with nonviable Lactobacillus GG cells was also significantly elevated (P< 0.05) compared to those from OVA immunized mice. The spleen cells of mice fed with non-viable Lactobacillus GG cells secreted more IL-6 (P< 0.01). These results suggest that the non-viable Lactobacillus GG can augment the systemic and mucosal immune responses in a host animal favoring secretory IgA but not IgE in an adjuvant-like manner.     

Antibody-antigen interaction in the airway drives early granulocyte recruitment through BLT1

Antibody-antigen interactions in the airway initiate inflammation in acute asthma exacerbations. This inflammatory response is characterized by the recruitment of granulocytes into the airways. In murine models of asthma, granulocyte recruitment into the lung contributes to the development of airway hyperresponsiveness (AHR), mucus production, and airway remodeling. Leukotriene B4 is a mediator released following antigen challenge that has chemotactic activity for granulocytes, mediated through its receptor, BLT1. We investigated the role of BLT1 in granulocyte recruitment following antigen challenge. Wild-type mice and BLT1-/- mice were sensitized and challenged with ovalbumin (OVA) to induce acute allergic airway inflammation. In addition, to explore the relevance to antibody-antigen interactions, we injected OVA bound to anti-OVA IgG1 or anti-OVA IgE intratracheally into na?ve wild-type and BLT1-/- mice. Cell composition of the lungs, cytokine levels, histology, and AHR were determined. After sensitization and challenge with ovalbumin, there was significantly reduced neutrophil and eosinophil recruitment into the airways of BLT1-/- mice compared with wild-type animals after one or two daily antigen challenges, but this difference was not seen after three or four daily antigen challenges. Mucus production and AHR were not affected. Intratracheal injection of OVA bound to IgG1 or IgE induced neutrophil recruitment into the airways in wild-type mice but not in the BLT1-/- mice. We conclude that BLT1 mediates early recruitment of granulocytes into the airway in response to antigen-antibody interactions in a murine model of acute asthma.     

IgE-selective and antigen-specific unresponsiveness in mice. I. Induction of the unresponsiveness by administration of ovalbumin-pullulan conjugate.

An experimental model was demonstrated in mice for the induction of IgE-selective unresponsiveness to ovalbumin, a protein antigen. An administration of ovalbumin, conjugated with pullulan, a linear polymer of glucose, (OA-pullulan) into mice resulted in the induction of a long lasting, IgE-selective unresponsiveness to the subsequent immunization with native OA in the form optimal to elicit IgE antibody response. The IgE-selective unresponsiveness is antigen specific and is infectious to normal mice by transferring the spleen cells from mice receiving OA-pullulan conjugate at least 2 weeks before. In contrast to other modified antigens, OA-pullulan was found to elicit good IgM and IgG antibody responses, but not an IgE response, without the aid of an adjuvant.     

Reaginic antibody formation in the mouse. VII. Depression of the ongoing IgE antibody formation by suppressor T cells.

The ongoing IgE antibody formation against ovalbumin (OA) in high responder mice was depressed by i.v. injections of either native or urea-denatured ovalbumin (UD-OA). Adoptive transfer experiments to determine the helper function of spleen cells from the treated animals showed that helper function for both IgE and IgG antibody responses diminished after treatment. Evidence was obtained that treatment suppressed the expansion of IgE-G memory cells. When the same treatment with OA or UD-OA was given to OA-primed mice before the appearance of IgE antibody in their serum, OA-specific splenic suppressor T cells were demonstrable. Thus, the transfer of splenic T cells from treated mice into normal mice suppressed the primary IgE and IgG antibody responses of the recipeints to DNP-OA. It was also found that the transfer of the splenic T cells from UD-OA-treated mice into OA-primed mice depressed ongoing IgE antibody formation in the recipients. The results suggested strongly that the decrease of helper function and the depression of ongoing IgE antibody formation by repeated injections of UD-OA was caused by generation of antigen (OA)-specific suppressor T cells.     

Haemophilus influenzae infection drives IL-17-mediated neutrophilic allergic airways disease

A subset of patients with stable asthma has prominent neutrophilic and reduced eosinophilic inflammation, which is associated with attenuated airways hyper-responsiveness (AHR). Haemophilus influenzae has been isolated from the airways of neutrophilic asthmatics; however, the nature of the association between infection and the development of neutrophilic asthma is not understood. Our aim was to investigate the effects of H. influenzae respiratory infection on the development of hallmark features of asthma in a mouse model of allergic airways disease (AAD). BALB/c mice were intraperitoneally sensitized to ovalbumin (OVA) and intranasally challenged with OVA 12-15 days later to induce AAD. Mice were infected with non-typeable H. influenzae during or 10 days after sensitization, and the effects of infection on the development of key features of AAD were assessed on day 16. T-helper 17 cells were enumerated by fluorescent-activated cell sorting and depleted with anti-IL-17 neutralizing antibody. We show that infection in AAD significantly reduced eosinophilic inflammation, OVA-induced IL-5, IL-13 and IFN-γ responses and AHR; however, infection increased airway neutrophil influx in response to OVA challenge. Augmented neutrophilic inflammation correlated with increased IL-17 responses and IL-17 expressing macrophages and neutrophils (early, innate) and T lymphocytes (late, adaptive) in the lung. Significantly, depletion of IL-17 completely abrogated infection-induced neutrophilic inflammation during AAD. In conclusion, H. influenzae infection synergizes with AAD to induce Th17 immune responses that drive the development of neutrophilic and suppress eosinophilic inflammation during AAD. This results in a phenotype that is similar to neutrophilic asthma. Infection-induced neutrophilic inflammation in AAD is mediated by IL-17 responses.     

Intranasal mite allergen induces allergic asthma-like responses in NC/Nga mice

Airway responses induced by intranasal administration of mite allergen without adjuvant were studied in NC/Nga mice. A crude extract of Dermatophagoides farinae (Df) was administered for 5 consecutive days and a single intranasal challenge booster dose was given 1 week after the last sensitization. 24 h after the single challenge, the airway hyperresponsiveness (AHR) was measured and the bronchoalveolar lavage fluid (BALF) was analyzed for numbers of eosinophils and neutrophils, and both cytokine and chemokine levels. There were marked increases in number of eosinophils in the BALF, AHR, Th2 cytokines (IL-5 and IL-13), and chemokine (eotaxin-1 and eotaxin-2) levels in the BALF following Df exposure. C57BL/6N, A/J, BALB/c, and CBA/JN mouse strains were also exposed to Df crude extract, but all of the measured responses were strongest in NC/Nga mice. Furthermore, Df-exposed NC/Nga mice showed the goblet cell hyperplasia, pulmonary eosinophilic inflammation, and increases in both total serum IgE and Df-specific IgG1. After intranasal exposure of NC/Nga mice to crude extract of Dermatophagoides pteronyssinus, the BALF eosinophilia and AHR were similar to responses induced by Df. None of the study parameters were increased in response to intranasal exposure to ovalbumin. These data demonstrated that NC/Nga mice developed allergic asthma-like responses after intranasal exposure to mite allergens.     

Effects of thioredoxin on established airway remodeling in a chronic antigen exposure asthma model

The development and treatment of asthma remains a subject of considerable interest in the medical community. Previous studies implicate an important role of cytokines in the pathology of asthma. In this current study, we examined whether redox-active protein thioredoxin 1 (TRX1) could prevent airway remodeling in an ovalbumin (OVA)-driven mouse chronic antigen exposure asthma model. Balb/c mice were sensitized and then challenged nine times with OVA (days 19-45). In this protocol, airway remodeling was established by day 34. Administration of recombinant human TRX1 during antigen challenge (days 18-32) significantly inhibited airway remodeling, eosinophilic pulmonary inflammation, airway hyperresponsiveness and resulted in decreased lung expression of eotaxin, macrophage inflammatory protein-1alpha and IL-13. Airway remodeling and eosinophilic pulmonary inflammation was also prevented in chronic OVA-exposed Balb/c human TRX1 transgenic mice. Importantly, TRX1-administration, after the establishment of airway remodeling (days 35-45), resulted in improved airway pathology. Our results suggest TRX1 prevents the development of airway remodeling, and also improves established airway remodeling by inhibiting production of chemokines and Th2 cytokines in the lungs.     

Endotoxin contamination of ovalbumin suppresses murine immunologic responses and development of airway hyper-reactivity

The reversible airway hyper-reactivity (AHR) of asthma is modeled by sensitizing and challenging mice with aerosolized ovalbumin. However, the C57BL/6 murine strain does not display the large increase in circulating IgG and IgE antibodies found in human atopy and asthma. We found that commercial ovalbumin was contaminated with lipopolysaccharide (LPS) in amounts sufficient to fully activate endothelial cells in an in vitro assay of the first step of inflammation. Desensitization of TLR4 by LPS pretreatment suppressed the inflammatory effect of ovalbumin. The presence of LPS was occult, because it does not require serum presentation and, like the LPS of Salmonella minnesota, was not suppressed by polymyxin B. Purified ovalbumin did not activate endothelial cells in vitro; however, endotoxin-free ovalbumin was far more effective than commercial material in stimulating IgE production and respiratory dysfunction in a C57BL/6 murine model of AHR. Moreover, endotoxin-free ovalbumin induced lung inflammation with alveolar enlargement and destruction in a histologic pattern that differed from the changes caused by commercial, endotoxin-contaminated ovalbumin. Reconstitution of purified ovalbumin with S. minnesota LPS decreased lung inflammation, decreased changes in lung function, and suppressed anti-ovalbumin antibody production. We conclude endotoxin contaminates ovalbumin preparations and that endotoxin co-administration with the ovalbumin antigen creates a state of tolerance in a murine model of AHR. Co-exposure to endotoxin and antigen occurs in humans through organic dusts, so murine models of AHR may reflect the clinical situation, but models based on commercial ovalbumin do not accurately reflect the effect of protein antigen alone on animal physiology.     

Immunomodulatory Effects of Escherichia coli ATCC 25922 on Allergic Airway Inflammation in a Mouse Model

Background

Hygiene hypothesis demonstrates that the lack of microbial exposure would promote the development of allergic airway disease (AAD). Therefore, the gut microbiota, including Escherichia coli (E. coli), would probably offer a potential strategy for AAD.

Objective

To investigate whether E. coli infection is able to suppress the induction of AAD and to elucidate the underlying mechanisms.

Methods

Nonpathogenic E. coli ATCC 25922 was infected by gavage before AAD phase in three patterns: 10⁸ or 10⁶ CFU in neonates or 10⁸ CFU in adults. Then mice were sensitized and challenged with ovalbumin (OVA) to induce allergic inflammation in both the upper and lower airways. Hallmarks of AAD, in terms of eosinophil infiltration and goblet cell metaplasia in subepithelial mucosa, Th2 skewing of the immune response, and levels of T regulate cells (Tregs), were examined by histological analysis, ELISA, and flow cytometry, respectively.

Results

E. coli, especially neonatally infected with an optimal dose, attenuated allergic responses, including a decrease in nasal rubbing and sneezing, a reduction in eosinophil inflammation and goblet cell metaplasia in subepithelial mucosa, decreased serum levels of OVA-specific IgE, and reduced Th2 (IL-4) cytokines. In contrast, this effect came with an increase of Th1 (IFN-r and IL-2) cytokines, and an enhancement of IL-10-secreting Tregs in paratracheal lymph nodes (PTLN).

Conclusion

E. coli suppresses allergic responses in mice, probably via a shift from Th1 to Th2 and/or induction of Tregs. Moreover, this infection is age- and dose-dependent, which may open up novel possibilities for new therapeutic interventions.     

Analysis of Pulmonary Dendritic Cell Maturation and Migration during Allergic Airway Inflammation

Dendritic cells (DCs) are the key players involved in initiation of adaptive immune response by activating antigen-specific T cells. DCs are present in peripheral tissues in steady state; however in response to antigen stimulation, DCs take up the antigen and rapidly migrate to the draining lymph nodes where they initiate T cell response against the antigen^1,2. Additionally, DCs also play a key role in initiating autoimmune as well as allergic immune response³.DCs play an essential role in both initiation of immune response and induction of tolerance in the setting of lung environment⁴. Lung environment is largely tolerogenic, owing to the exposure to vast array of environmental antigens⁵. However, in some individuals there is a break in tolerance, which leads to induction of allergy and asthma. In this study, we describe a strategy, which can be used to monitor airway DC maturation and migration in response to the antigen used for sensitization. The measurement of airway DC maturation and migration allows for assessment of the kinetics of immune response during airway allergic inflammation and also assists in understanding the magnitude of the subsequent immune response along with the underlying mechanisms.Our strategy is based on the use of ovalbumin as a sensitizing agent. Ovalbumin-induced allergic asthma is a widely used model to reproduce the airway eosinophilia, pulmonary inflammation and elevated IgE levels found during asthma^6,7. After sensitization, mice are challenged by intranasal delivery of FITC labeled ovalbumin, which allows for specific labeling of airway DCs which uptake ovalbumin. Next, using several DC specific markers, we can assess the maturation of these DCs and can also assess their migration to the draining lymph nodes by employing flow cytometry.     

Allergy influences the inflammatory status of the brain and enhances tau-phosphorylation

Despite the existing knowledge regarding the neuropathology of Alzheimer's disease (AD), the cause of sporadic forms of the disease is unknown. It has been suggested that systemic inflammation may have a role, but the exact mechanisms through which inflammatory processes influence the pathogenesis and progress of AD are not obvious. Allergy is a chronic inflammatory disease affecting more than 20% of the Western population, but the effects of allergic conditions on brain functions are largely unknown. The aim of this study was to investigate whether or not chronic peripheral inflammation associated with allergy affects the expression of AD-related proteins and inflammatory markers in the brain. On the basis of previously described models for allergy in mice we developed a model of chronic airway allergy in mouse, with ovalbumin as allergen. The validity of the chronic allergy model was confirmed by a consistent and reproducible eosinophilia in the bronchoalveolar lavage (BAL) fluid of allergic animals. Allergic mice were shown to have increased brain levels of both immunoglobulin (Ig) G and IgE with a widespread distribution. Allergy was also found to increase phosphorylation of tau protein in the brain. The present data support the notion that allergy-dependent chronic peripheral inflammation modifies the brain inflammatory status, and influences phosphorylation of an AD-related protein, indicating that allergy may be yet another factor to be considered for the development and/or progression of neurodegenerative diseases such as AD.     

Tidal midexpiratory flow as a measure of airway hyperresponsiveness in allergic mice

A method for the noninvasive measurement of airway responsiveness was validated in allergic BALB/c mice. With head-out body plethysmography and the decrease in tidal midexpiratory flow (EF(50)) as an indicator of airway obstruction, responses to inhaled methacholine (MCh) and the allergen ovalbumin were measured in conscious mice. Allergen-sensitized and -challenged mice developed airway hyperresponsiveness as measured by EF(50) to aerosolized MCh compared with that in control animals. This response was associated with increased allergen-specific IgE and IgG1 production, increased levels of interleukin-4 and interleukin-5 in bronchoalveolar lavage fluid and eosinophilic lung inflammation. Ovalbumin aerosol challenge elicited no acute bronchoconstriction but resulted in a significant decline in EF(50) baseline values 24 h after challenge in allergic mice. The decline in EF(50) to MCh challenge correlated closely with simultaneous decreases in pulmonary conductance and dynamic compliance. The decrease in EF(50) was partly inhibited by pretreatment with the inhaled beta(2)-agonist salbutamol. We conclude that measurement of EF(50) to inhaled bronchoconstrictors by head-out body plethysmography is a valid measure of airway hyperresponsiveness in mice.     

Characterization of NLRP12 during the development of allergic airway disease in mice

Among the 22 members of the nucleotide binding-domain, leucine rich repeat-containing (NLR) family, less than half have been functionally characterized. Of those that have been well studied, most form caspase-1 activating inflammasomes. NLRP12 is a unique NLR that has been shown to attenuate inflammatory pathways in biochemical assays and mediate the lymph node homing of activated skin dendritic cells in contact hypersensitivity responses. Since the mechanism between these two important observations remains elusive, we further evaluated the contribution of NLRP12 to organ specific adaptive immune responses by focusing on the lung, which, like skin, is exposed to both exogenous and endogenous inflammatory agents. In models of allergic airway inflammation induced by either acute ovalbumin (OVA) exposure or chronic house dust mite (HDM) antigen exposure, Nlrp12(-/-) mice displayed subtle differences in eosinophil and monocyte infiltration into the airways. However, the overall development of allergic airway disease and airway function was not significantly altered by NLRP12 deficiency. Together, the combined data suggest that NLRP12 does not play a vital role in regulating Th2 driven airway inflammation using common model systems that are physiologically relevant to human disease. Thus, the allergic airway inflammation models described here should be appropriate for subsequent studies that seek to decipher the contribution of NLRP12 in mediating the host response to agents associated with asthma exacerbation.