Persistence of bronchopulmonary hyper-reactivity and eosinophilic lung inflammation after anti-IL-5 or -IL-13 treatment in allergic BALB/c and IL-4Ralpha knockout mice

Evaluation of the therapeutic effects of oestradiol on the systemic inflammatory response and on lung injury caused by the occlusion of the proximal descending aorta in male rats

OBJECTIVES

Ischaemia and reperfusion-induced microvascular dysfunction is a serious problem encountered during a variety surgical procedures, leading to systemic inflammation and affecting remote organs, specially the lungs. 17β-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17β-oestradiol therapeutic effects after aortic ischaemia and reperfusion (I/R) by evaluating lung inflammation.

METHODS

Twenty-four Wistar rats were submitted to I/R by insufflation of a 2-F catheter in thoracic aorta for 20 min. Reperfusion took 4 h and 17β-oestradiol (280 µg/kg, i.v.) was administered after 1 h of reperfusion. Sham-operated rats were controls. Bronchoalveolar lavage was performed and lung samples were prepared for histopathological analysis and tissue culture (explant). Interleukin (IL)-1β, IL-10 and tumour necrosis factor-α were quantified.

RESULTS

After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17β-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17β-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1β increased after I/R and 17β-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1β and IL-10 in lung explants, reduced by 17β-oestradiol.

CONCLUSIONS

Our results showed that 17β-oestradiol treatment performed in the period of reperfusion, modulated the systemic response and the lung repercussions of I/R by thoracic aortic occlusion. Thus, we can suggest that 17β-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.

Paneth Cell-Derived Lysozyme Defines the Composition of Mucolytic Microbiota and the Inflammatory Tone of the Intestine

Paneth cells are the primary source of C-type lysozyme, a β-1,4-N-acetylmuramoylhydrolase that enzymatically processes bacterial cell walls. Paneth cells are normally present in human cecum and ascending colon, but are rarely found in descending colon and rectum; Paneth cell metaplasia in this region and aberrant lysozyme production are hallmarks of inflammatory bowel disease (IBD) pathology. Here, we examined the impact of aberrant lysozyme production in colonic inflammation. Targeted disruption of Paneth cell lysozyme (Lyz1) protected mice from experimental colitis. Lyz1-deficiency diminished intestinal immune responses to bacterial molecular patterns and resulted in the expansion of lysozyme-sensitive mucolytic bacteria, including Ruminococcus gnavus, a Crohn's disease-associated pathobiont. Ectopic lysozyme production in colonic epithelium suppressed lysozyme-sensitive bacteria and exacerbated colitis. Transfer of R. gnavus into Lyz1^-/- hosts elicited a type 2 immune response, causing epithelial reprograming and enhanced anti-colitogenic capacity. In contrast, in lysozyme-intact hosts, processed R. gnavus drove pro-inflammatory responses. Thus, Paneth cell lysozyme balances intestinal anti- and pro-inflammatory responses, with implications for IBD.

Acute effects of estradiol on lung inflammation due to intestinal ischemic insult in male rats

Intestinal ischemia and reperfusion (intestinal I/R) causes acute lung inflammation that is characterized by leukocyte migration, increased lung microvascular permeability, and, in severe forms, noncardiogenic pulmonary edema and acute respiratory distress syndrome. Female sex hormones interfere with immune response, and experimental and clinical evidence shows that females are more resistant than males to organ injury caused by gut trauma. To reduce the lung inflammation caused by intestinal I/R, we have acutely treated male rats with estradiol. Intestinal I/R was performed by the clamping (45 min) of the superior mesenteric artery (SMA), followed by 2 h of intestinal reperfusion (unclamping SMA). Groups of rats received 17β estradiol (E2, 280 µg/kg, i.v., single dose) 30 min after the SMA occlusion (ischemia period) or 1 h after the unclamping of SMA (reperfusion period). Leukocytes influx into the lung and microvascular leakage were assessed by lung myeloperoxidase activity and Evans blue dye extravasation, respectively. The lung expression of adhesion molecules (intercellular adhesion molecule 1, platelet endothelial cell adhesion molecule 1, and vascular cell adhesion molecule [VCAM]) was evaluated by immunohistochemistry. Interleukin 1β (IL-1β), IL-10, and NOx concentrations were quantified in supernatants of cultured lung tissue. We have found that intestinal I/R increased the lung myeloperoxidase activity and Evans blue dye extravasation, which were reduced by treatment of rats with E2. Intestinal I/R increased ICAM-1 expression only, and it was decreased by E2 treatment. However, E2 treatment reduced the basal expression of platelet endothelial cell adhesion molecule 1. E2 treatment during intestinal ischemia was effective to reduce the levels of IL-10 and IL-1β in explant supernatant, but only IL-10 levels were reduced by E2 at reperfusion phase. The treatment with E2 did not affect NOx concentration. Taken together, our data suggest that estradiol modulates the lung inflammatory response induced by lung injury, likely by acute effects. Thus, acute estradiol treatment could be considered as a potential therapeutic agent in ischemic events.

The putative role of ovary removal and progesterone when considering the effect of formaldehyde exposure on lung inflammation induced by ovalbumin

OBJECTIVE

Formaldehyde exposure during the menstrual cycle is known to affect the course of allergic lung inflammation. Because our previous data demonstrated that formaldehyde combined with an ovariectomy reduced allergic lung inflammation, we investigated the putative role of ovary removal and progesterone treatment when considering the effect of formaldehyde on allergic lung inflammation.

METHOD

Ovariectomized rats and their matched controls were exposed to formaldehyde (1%, 3 days, 90 min/day) or vehicle, and immediately after exposure, the rats were sensitized to ovalbumin by a subcutaneous route. After 1 week, the rats received a booster by the same route, and after an additional week, the rats were challenged with ovalbumin (1%) by an aerosol route. The leukocyte numbers, interleukin-10 (IL-10) release, myeloperoxidase activity, vascular permeability, ex vivo tracheal reactivity to methacholine and mast cell degranulation were determined 24 h later.

RESULTS

Our results showed that previous exposure to formaldehyde in allergic rats decreased lung cell recruitment, tracheal reactivity, myeloperoxidase activity, vascular permeability and mast cell degranulation while increasing IL-10 levels. Ovariectomy only caused an additional reduction in tracheal reactivity without changing the other parameters studied. Progesterone treatment reversed the effects of formaldehyde exposure on ex vivo tracheal reactivity, cell influx into the lungs and mast cell degranulation.

CONCLUSION

In conclusion, our study revealed that formaldehyde and ovariectomy downregulated allergic lung inflammation by IL-10 release and mast cell degranulation. Progesterone treatment increased eosinophil recruitment and mast cell degranulation, which in turn may be responsible for tracheal hyperreactivity and allergic lung inflammation.

Formaldehyde inhalation reduces respiratory mechanics in a rat model with allergic lung inflammation by altering the nitric oxide/cyclooxygenase-derived products relationship

Bronchial hyperresponsiveness is a hallmark of asthma and many factors modulate bronchoconstriction episodes. A potential correlation of formaldehyde (FA) inhalation and asthma has been observed; however, the exact role of FA remains controversial. We investigated the effects of FA inhalation on Ovalbumin (OVA) sensitisation using a parameter of respiratory mechanics. The involvement of nitric oxide (NO) and cyclooxygenase-derived products were also evaluated. The rats were submitted, or not, to FA inhalation (1%, 90 min/day, 3 days) and were OVA-sensitised and challenged 14 days later. Our data showed that previous FA exposure in allergic rats reduced bronchial responsiveness, respiratory resistance (Rrs) and elastance (Ers) to methacholine. FA exposure in allergic rats also increased the iNOS gene expression and reduced COX-1. L-NAME treatment exacerbated the bronchial hyporesponsiveness and did not modify the Ers and Rrs, while Indomethacin partially reversed all of the parameters studied. The L-NAME and Indomethacin treatments reduced leukotriene B₄ levels while they increased thromboxane B₂ and prostaglandin E₂. In conclusion, FA exposure prior to OVA sensitisation reduces the respiratory mechanics and the interaction of NO and PGE₂ may be representing a compensatory mechanism in order to protect the lung from bronchoconstriction effects.

Anti-inflammatory effects of inosine in allergic lung inflammation in mice: evidence for the participation of adenosine A2A and A 3 receptors

Inosine, a naturally occurring purine formed from the breakdown of adenosine, is associated with immunoregulatory effects. Evidence shows that inosine modulates lung inflammation and regulates cytokine generation. However, its role in controlling allergen-induced lung inflammation has yet to be identified. In this study, we aimed to investigate the role of inosine and adenosine receptors in a murine model of lung allergy induced by ovalbumin (OVA). Intraperitoneal administration of inosine (0.001-10 mg/kg, 30 min before OVA challenge) significantly reduced the number of leukocytes, macrophages, lymphocytes and eosinophils recovered in the bronchoalveolar lavage fluid of sensitized mice compared with controls. Interestingly, our results showed that pre-treatment with the selective A2A receptor antagonist (ZM241385), but not with the selective A2B receptor antagonist (alloxazine), reduced the inhibitory effects of inosine against macrophage count, suggesting that A2A receptors mediate monocyte recruitment into the lungs. In addition, the pre-treatment of mice with selective A3 antagonist (MRS3777) also prevented inosine effects against macrophages, lymphocytes and eosinophils. Histological analysis confirmed the effects of inosine and A2A adenosine receptors on cell recruitment and demonstrated that the treatment with ZM241385 and alloxazine reverted inosine effects against mast cell migration into the lungs. Accordingly, the treatment with inosine reduced lung elastance, an effect related to A2 receptors. Moreover, inosine reduced the levels of Th2-cytokines, interleukin-4 and interleukin-5, an effect that was not reversed by A2A or A2B selective antagonists. Our data show that inosine acting on A2A or A3 adenosine receptors can regulate OVA-induced allergic lung inflammation and also implicate inosine as an endogenous modulator of inflammatory processes observed in the lungs of asthmatic patients.

Long-term amphetamine treatment exacerbates inflammatory lung reaction while decreases airway hyper-responsiveness after allergic stimulus in rats

Asthma is an allergic lung disease can be modulated by drugs that modify the activity of central nervous system (CNS) such as amphetamine (AMPH). AMPH is a highly abused drug that exerts potent effects on behavior and immunity. In this study we investigated the mechanism involved in the effects of long-term AMPH treatment on the increased magnitude of allergic lung response. We evaluated mast cells degranulation, cytokines release, airways responsiveness and, expression of adhesion molecules. Male Wistar rats were treated with AMPH or vehicle (PBS) for 21 days and sensitized with ovalbumin (OVA) one week after the first injection of vehicle or AMPH. Fourteen days after the sensitization, the rats were challenged with an OVA aerosol, and 24h later their parameters were analyzed. In allergic rats, the treatment with AMPH exacerbated the lung cell recruitment due increased expression of ICAM-1, PECAM-1 and Mac-1 in granulocytes and macrophages recovered from bronchoalveolar lavage. Elevated levels of IL-4, but decreased levels of IL-10 were also found in samples of lung explants after AMPH treatment. Conversely, the ex-vivo tracheal hyper-responsiveness to methacholine (MCh) was reduced by AMPH treatment, whereas the force contraction of tracheal segments due to in vitro antigen challenge remained unaltered. Our findings suggest that lung inflammation and airway hyper-responsiveness due to OVA challenge are under the distinct control of AMPH during long-term treatment. Our data strongly indicate that AMPH positively modulates allergic lung inflammation via the increase of ICAM-1, PECAM-1, Mac-1 and IL-4. AMPH also abrogates the release of the anti-inflammatory cytokine IL-10.

3,4-methylenedioxymethamphetamine (ecstasy) decreases inflammation and airway reactivity in a murine model of asthma

OBJECTIVE

3,4-Methylenedioxymethamphetamine (MDMA), or ecstasy, is a synthetic drug used recreationally, mainly by young people. It has been suggested that MDMA has a Th cell skewing effect, in which Th1 cell activity is suppressed and Th2 cell activity is increased. Experimental allergic airway inflammation in ovalbumin (OVA)-sensitized rodents is a useful model to study Th2 response; therefore, based on the Th2 skewing effect of MDMA, we studied MDMA in a model of allergic lung inflammation in OVA-sensitized mice.

METHODS

We evaluated cell trafficking in the bronchoalveolar lavage fluid, blood and bone marrow; cytokine production; L-selectin expression and lung histology. We also investigated the effects of MDMA on tracheal reactivity in vitro and mast cell degranulation.

RESULTS

We found that MDMA given prior to OVA challenge in OVA-sensitized mice decreased leukocyte migration into the lung, as revealed by a lower cell count in the bronchoalveolar lavage fluid and lung histologic analysis. We also showed that MDMA decreased expression of both Th2-like cytokines (IL-4, IL-5 and IL-10) and adhesion molecules (L-selectin). Moreover, we showed that the hypothalamus-pituitary-adrenal axis is partially involved in the MDMA-induced reduction in leukocyte migration into the lung. Finally, we showed that MDMA decreased tracheal reactivity to methacholine as well as mast cell degranulation in situ.

CONCLUSIONS

Thus, we report here that MDMA given prior to OVA challenge in OVA-sensitized allergic mice is able to decrease lung inflammation and airway reactivity and that hypothalamus-pituitary-adrenal axis activation is partially involved. Together, the data strongly suggest an involvement of a neuroimmune mechanism in the effects of MDMA on lung inflammatory response and cell recruitment to the lungs of allergic animals.

Amphetamine modulates cellular recruitment and airway reactivity in a rat model of allergic lung inflammation

Asthma is characterized by pulmonary cellular infiltration, vascular exudation and airway hyperresponsiveness. Several drugs that modify central nervous system (CNS) activity can modulate the course of asthma. Amphetamine (AMPH) is a highly abused drug that presents potent stimulating effects on the CNS and has been shown to induce behavioral, biochemical and immunological effects. The purpose of this study was to investigate the effects of AMPH on pulmonary cellular influx, vascular permeability and airway reactivity. AMPH effects on adhesion molecule expression, IL-10 and IL-4 release and mast cell degranulation were also studied. Male Wistar rats were sensitized with ovalbumin (OVA) plus alum via subcutaneous injection. One week later, the rats received another injection of OVA-alum (booster). Two weeks after this booster, the rats were subjected to AMPH treatment 12 h prior to the OVA airway challenge. In rats treated with AMPH, the OVA challenge reduced cell recruitment into the lung, the vascular permeability and the cellular expression of ICAM-1 and Mac-1. Additionally, elevated levels of IL-10 and IL-4 were found in samples of lung explants from allergic rats. AMPH treatment, in comparison, increased IL-10 levels but reduced those of IL-4 in the lung explants. Moreover, the tracheal responsiveness to methacholine (MCh), as well as to an in vitro OVA challenge, was reduced by AMPH treatment, and levels of PCA titers were not modified by the drug. Our findings suggest that single AMPH treatment down-regulates several parameters of lung inflammation, such as cellular migration, vascular permeability and tracheal responsiveness. These results also indicate that AMPH actions on allergic lung inflammation include endothelium-leukocyte interaction mechanisms, cytokine release and mast cell degranulation.

Lidocaine-derivative JMF2-1 prevents ovalbumin-induced airway inflammation by regulating the function and survival of T cells

BACKGROUND

Inhalation of the local anaesthetic lidocaine has been suggested to be beneficial for asthmatics, but airway anaesthesia is unpleasant and may exacerbate bronchoconstriction. Our previous study showed that inhalation of the lidocaine analogue JMF2-1 can elicit the anti-inflammatory properties of lidocaine without anaesthesia. This prompted further research on the mechanism of action and putative therapeutic application of JMF2-1.

OBJECTIVE

We tested the hypothesis that JMF2-1 would prevent allergen-induced lung inflammation and airway hyperresponsiveness (AHR) by modulating T cell function in vivo and in vitro. Methods Local and systemic changes in leucocyte levels, cytokine production and lung mechanics were examined in a murine model of lung inflammation. JMF2-1 (0.05-2%) or saline was aerosolized twice a day during the ovalbumin (OVA)-provocation period (19-21 days post-sensitization). Analyses were performed 24 h after the final challenge. Primary cultured lymph node cells were used to assess the effects of JMF2-1 (100-600 μm) at the cellular level.

RESULTS

OVA challenge resulted in lung recruitment of CD4(+) T cells and eosinophils, increased generation of inflammatory cytokines and AHR to inhaled methacholine within 24 h. These changes were prevented by JMF2-1 nebulization, and occurred in parallel with an increase in the number of apoptotic cells in the lung. JMF2-1 treatment did not alter levels of CD4(+) or CD8(+) T cells in the thymus or lymph nodes of naïve mice, although it inhibited OVA-induced IL-13 production and the lymphocyte proliferative response in vitro. It also induced apoptosis of OVA-activated lymphocytes in a mechanism sensitive to z-VAD, indicating that JMF2-1 mediates caspase-dependent apoptosis.

CONCLUSION

Inhalation of JMF2-1 prevents the cardinal features of asthma by reducing T(H) 2 cytokine generation and lung eosinophilic inflammatory infiltrates via local inhibition of T cell function and survival. JMF2-1 may represent a novel therapeutic alternative for asthma control with distinct advantages over local anaesthetics.

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.

Intranasal challenge with increasing ovalbumin doses differently affects airway hyperresponsiveness and inflammatory cell accumulation in mouse model of asthma

OBJECTIVE

To investigate whether challenge with increasing allergen doses could differently affect allergen-induced airway hyperresponsiveness (AHR) and inflammatory cell accumulation in mouse model of asthma, providing an experimental model to investigate their relationship.

MATERIAL AND METHODS

AHR and accumulation of inflammatory cells in bronchoalveolar lavage fluid (BALF) and into the lungs were compared in ovalbumin-sensitized mice that were challenged intranasally with 2.5, 10, 25 or 100 microg of ovalbumin/mouse.

RESULTS

Both AHR and inflammatory cell accumulation were proportional to the ovalbumin dose used for challenge. However, in group challenged with 10 microg of ovalbumin airway inflammation was present, although allergen-induced AHR was not detected. Additional analysis indicated that neither mucous hyperproduction nor eosinophil degranulation could be correlated to presence of AHR in this model, whereas concentration of interleukin (IL)-13 in BALF was increased only in those groups in which AHR was present.

CONCLUSIONS

Altogether, intranasal challenge of mice with increasing allergen doses could serve as a suitable experimental system for investigation of mechanisms by which airway inflammation leads to allergen-induced AHR. Our initial findings are in line with previous reports that dissociate AHR from amount of eosinophil accumulation and imply the role of IL-13 in this process.

Interference of methysergide, a specific 5-hydroxytryptamine receptor antagonist, with airway chronic allergic inflammation and remodelling in a murine model of asthma

BACKGROUND

Airway remodelling encompasses the structural changes observed in asthmatic airways. Mast cells, through the release of histamine and 5-hydroxytryptamine (serotonin), are implicated in early asthmatic reactions, bronchoconstriction and mucosal oedema, and in the development of bronchial hyperresponsiveness. However, the association between serotonin and remodelling processes in murine model of airways inflammation remains to be elucidated.

OBJECTIVE

As serotonin is released by murine mast cells upon antigen challenge, we tested the hypothesis of its involvement in the development of inflammatory and remodelling processes in a murine model of chronic airway inflammation following prolonged allergen challenge. Methods BALB/c mice were exposed to aerosolized ovalbumin for 20 min 2 days a week, for 4 consecutive weeks. Two hours before each challenge, they were treated with methysergide (intranasally, 40 microg/kg). Forty-eight hours after the last aerosol challenge, bronchoalveolar lavage (BAL) and lung tissue were collected for analysis.

RESULTS

Methysergide inhibited the allergen-induced increase in airway eosinophilia, reduced T helper type 2 (Th2) cytokines in lung, spleen or thoracic lymph nodes, and specific IgE levels. The extravasation of plasma and fibronectin production in the lung, and collagen deposition in the lung were also inhibited after methysergide treatment. Although methysergide treatment induced an increase in IFN-gamma levels, experiments with neutralizing antibody suggest that this is not responsible for inhibition. In addition, instillation of serotonin to immunized mice induced eosinophil recruitment to BAL, Th2 cytokine production and fibronectin release in lung as well as collagen deposition.

CONCLUSION

Serotonin may contribute to the development and maintenance of remodelling through the release of cytokines and of fibrogenic mediators. Serotonin should therefore be considered as relevant for the development and maintenance of airway remodelling.

Arhgef1 is required by T cells for the development of airway hyperreactivity and inflammation

RATIONALE

Arhgef1 is an intracellular protein, expressed by hematopoietic cells, that regulates signaling by both G protein-coupled receptors and RhoA, and, consequently, is required for appropriate migration and adhesion of diverse leukocyte populations.

OBJECTIVES

To evaluate a possible contribution for Arhgef1 in the development of airway inflammation and airway hyperreactivity.

METHODS

Arhgef1-deficient (Arhgef1-/-) and wild-type (WT) mice were sensitized and airway challenged, followed by measurement of airway responsiveness to inhaled methacholine. Inflammation was assessed by several parameters that included flow cytometric analysis and histology. Arhgef1-deficient recipients were reconstituted with WT T lymphocytes before sensitization and challenge, and again measured for airway responsiveness and inflammation. Cytokine production in response to specific antigen was measured in cultures of isolated leukocytes from lung and spleen and compared with the levels generated in lung and spleen explant cultures.

MEASUREMENTS AND MAIN RESULTS

Arhgef1-/- mice display significantly reduced airway hyperreactivity, Th2 cytokine production, and lung inflammation, despite intact systemic immunity. After airway challenge of Arhgef1-/- mice, antigen-specific T cells were present in mutant lungs, but were found to interact with CD11c+ cells at a significantly reduced frequency. Adoptive transfer of WT T cells into Arhgef1-/- mice restored airway hyperreactivity and inflammation.

CONCLUSIONS

These data demonstrate that T cells depend on Arhgef1 to promote lung inflammation. Moreover, a deficiency in Arhgef1 results in reduced T cell-CD11c+ antigen-presenting cell interaction, and likely underscores the inability of Arhgef1-/- mice to mount an adaptive immune response to airway challenge.

Modulation of the induction of lung and airway allergy in the offspring of IFN-gamma-treated mother mice

Recent studies have highlighted the influence of fetal/maternal interactions on the development of asthma. Because IFN-gamma reduces Th2-mediated allergic responses, we assessed its capacity to modulate asthma in the offspring when injected into mothers during pregnancy. IFN-gamma was injected in CD1 female mice on day 6.5 of gestation. Immediately after birth, male newborns were housed in cages with interchanged mothers: the offspring from IFN-gamma-treated mothers were breastfed by normal mothers (IFN/nor), and those from normal mothers were breastfed by IFN-gamma-treated (Nor/IFN) or normal mothers (Nor/nor). Immediately after weaning, the spleen cells from IFN/nor and Nor/IFN mice produced less IL-4 and more IFN-gamma than Nor/nor mice when stimulated with Con A. At the age of 6-7 wk, mice were immunized with OVA on days 0 and 7. From day 14 to 16, they were exposed to aerosolized OVA. The bronchoalveolar lavage fluid from Nor/nor mice showed eosinophilia, a large number of these cells being present in perivascular and peribronchial regions of lung tissues. IFN/nor or Nor/IFN mice showed greatly reduced eosinophil numbers in bronchoalveolar lavage fluid. In addition, lung sections from IFN/nor, but not Nor/IFN mice showed almost normal histology. In OVA-sensitized IFN/nor and Nor/IFN mice, the production of IFN-gamma, IL-4, and IL-5 by spleen cells was significantly reduced as compared with cells from the OVA-sensitized Nor/nor group. IgE and anaphylactic IgG1 were also reduced in plasma of IFN/nor mice. In conclusion, the presence of IFN-gamma during pregnancy confers to the fetus a protection against allergenic provocations in the adult life.

Inhibition of human interleukin-13-induced respiratory and oesophageal inflammation by anti-human-interleukin-13 antibody (CAT-354)

BACKGROUND

Allergic asthma is a complex disorder characterized by local and systemic T helper type 2 -cell responses such as the production of IL-13, a cytokine associated with the induction of airway hyper-responsiveness (AHR), chronic pulmonary eosinophilia, airway mucus overproduction and eosinophilic oesophagitis.

OBJECTIVE

Our study aimed to address the therapeutic potential of a human anti-human IL-13 IgG4 monoclonal antibody (CAT-354) in a murine model of respiratory and oesophageal inflammation induced by intratracheal human IL-13.

METHODS

BALB/c mice were treated on days 1 and 3 with CAT-354 (intraperitoneal injection), and human IL-13 was injected intratracheally on days 2 and 4. AHR to methacholine, airway eosinophilia in bronchoalveolar lavage fluid, histologic analysis of goblet cell metaplasia and oesophageal eosinophilia were evaluated.

RESULTS

Human IL-13 induced airway eosinophilia and goblet cell metaplasia in mice in a dose-dependent manner. Moreover, intratracheal dosing with 25 microg of human IL-13 was sufficient to induce AHR, goblet cell metaplasia and oesophageal eosinophilia. Pretreatment with CAT-354 significantly reduced AHR, airway eosinophilia and oesophageal eosinophilia.

CONCLUSION

These results demonstrate that anti-human IL-13 (CAT-354) is a potential therapeutic treatment for allergic airway and oesophageal diseases.

Allergen immunotherapy in the prevention of asthma

PURPOSE OF REVIEW

Asthma is a disease causing significant morbidity and mortality. In the recent past, there has been an explosion of pharmacotherapeutic options attempting to control the disease. Unfortunately, none of the current options offers the promise of prevention or a permanent cure. However, there appear to be exciting, new data emerging to support the hypothesis that the prevention or early treatment of allergic rhinitis, such as with the use of allergen immunotherapy, may help mitigate the severity of bronchial symptoms and even prevent the development of asthma. In this paper, we review recent research published proposing immunotherapy as a means of preventing the development of, or at least ameliorating, allergic asthma.

RECENT FINDINGS

There is evidence that the upper and lower airways may be considered a single unit, with the nasal and bronchial mucosa having features in common. Epidemiological, pathophysiological and clinical studies have shown that they can be affected by similar inflammatory triggers, with interconnected mechanisms amplifying the inflammatory cascade. Allergic rhinitis is interrelated to, and is a risk factor for, the development of asthma. An evidence-based review validates the successful use of allergen immunotherapy in treating allergic rhinitis and asthma. There is promising evidence advocating its use in the prevention of clinical asthma.

SUMMARY

This article explores current research pertaining to the use of immunomodulation, such as by using allergen immunotherapy, to ameliorate and prevent the development of allergic asthma.

Effect of Mycobacterium tuberculosis chaperonins on bronchial eosinophilia and hyper-responsiveness in a murine model of allergic inflammation

BACKGROUND

Epidemiological evidence suggests that infection with Mycobacterium tuberculosis protects children against asthma. Several laboratories have shown that, in mouse models of allergic inflammation, administration of the whole live tuberculosis vaccine, Mycobacterium bovis bacillus Calmette-Guerin (BCG), prevents ovalbumin (OVA)-induced pulmonary eosinophilia.

OBJECTIVE

The aim of this study was to characterize specific M. tuberculosis molecules that are known to modulate immune responses to see if they affected pulmonary eosinophilia and bronchial hyper-responsiveness.

METHODS

C57Bl/6 mice were sensitized to OVA on days 0 and 7 and subsequently challenged with OVA on day 14 over a 3-day period. Pulmonary eosinophilia and bronchial hyper-responsiveness were measured 24 h following the last antigen challenge. In some groups, mice were pre-treated with M. tuberculosis or M. tuberculosis chaperonins (Cpns)60.1, 60.2 and 10, and the effect of this treatment on the allergic inflammatory response to aerosolized OVA was established.

RESULTS

We show that M. tuberculosis Cpns inhibit allergen-induced pulmonary eosinophilia in the mouse. Of the three Cpns produced by M. tuberculosis, Cpn60.1, Cpn10 and Cpn60.2, the first two are effective in preventing eosinophilia when administered by the intra-tracheal route. Furthermore, the increase in airways sensitivity to inhaled methacholine following OVA challenge of immunized mice was suppressed following treatment with Cpn60.1. The allergic inflammatory response was also characterized by an increase in Th2 cytokines IL-4 and IL-5 in bronchoalveolar lavage fluid, which was also suppressed following treatment with Cpn60.1.

CONCLUSION

These data show that bacterial Cpns can suppress eosinophil recruitment and bronchial hyper-responsiveness in a murine model of allergic inflammation.

Differential regulation of the release of tumor necrosis factor-alpha and of eicosanoids by mast cells in rat airways after antigen challenge

BACKGROUND: Rat trachea display a differential topographical distribution of connective tissue mast cells (CTMC) and mucosal mast cells (MMC) that may imply regional differences in the release of allergic mediators such as tumor necrosis factor-alpha (TNF-alpha) and eicosanoids. AIM: To evaluate the role of CTMC and MMC for release of TNF-alpha and eicosanoids after allergenic challenge in distinct segments of rat trachea. MATERIALS AND METHODS: Proximal trachea (PT) and distal trachea (DT) from ovalbumin (OVA)-sensitized rats, treated or not with compound 48/80 (48/80) or dexamethasone, were incubated in culture medium. After OVA challenge, aliquots were collected to study release of TNF-alpha and eicosanoids. RESULTS: Release of TNF-alpha by PT upon OVA challenge peaked at 90 min and decayed at 6 and 24 h. Release from DT peaked at 30-90 min and decayed 6 and 24 h later. When CTMC were depleted with 48/80, OVA challenge exacerbated the TNF-alpha release by PT at all time intervals, while DT exacerbated TNF-alpha levels 6 and 24 h later only. Dexamethasone reduced TNF-alpha production after 90 min of OVA challenge in PT and at 3 and 6h in DT. OVA challenge increased prostaglandin D2) in DT and leukotriene B4 in both segments but did not modify prostaglandin E2 and leukotriene C4 release. CONCLUSION: OVA challenge induces TNF-alpha release from MMC, which is negatively regulated by CTMC. The profile of TNF-alpha and eicosanoids depends on the time after OVA challenge and of the tracheal segment considered.

Respiratory syncytial virus, pneumonia virus of mice, and influenza A virus differently affect respiratory allergy in mice

BACKGROUND

Respiratory viral infections in early childhood may interact with the immune system and modify allergen sensitization and/or allergic manifestations. In mice, respiratory syncytial virus (RSV) infection during allergic provocation aggravates the allergic T helper (Th) 2 immune response, characterized by the production of IL-4, IL-5, and IL-13, and inflammatory infiltrates. However, it is unclear whether the RSV-enhanced respiratory allergic response is a result of non-specific virus-induced damage of the lung, or virus-specific immune responses.

OBJECTIVE

In the present study we investigated whether RSV, pneumonia virus of mice (PVM) and influenza A virus similarly affect the allergic response.

METHODS

BALB/c mice were sensitized and challenged with ovalbumin (OVA), and inoculated with virus during the challenge period. Pulmonary inflammation, lung cytokine mRNA responses, and IgE production in serum were assessed after the last OVA-challenge.

RESULTS

Like RSV, PVM enhanced the OVA-induced pulmonary IL-4, IL-5, and IL-13 mRNA expression, which was associated with enhanced perivascular inflammation. In addition, PVM increased the influx of eosinophils in lung tissue. In contrast, influenza virus decreased the Th2 cytokine mRNA expression in the lungs. However, like PVM, influenza virus enhanced the pulmonary eosinophilic infiltration in OVA-allergic mice.

CONCLUSION

The Paramyxoviruses RSV and PVM both are able to enhance the allergic Th2 cytokine response and perivascular inflammation in BALB/c mice, while the Orthomyxovirus influenza A is not.