Protective effects of cyclophosphamide, cyclosporin A and FK506 against antigen-induced lung eosinophilia in guinea-pigs

The JAK-3 inhibitor CP-690550 is a potent anti-inflammatory agent in a murine model of pulmonary eosinophilia

Janus kinase 3 (JAK-3) is a tyrosine kinase that has been shown to participate in the signaling of several cytokines that are believed to play a role in allergic airway disease, e.g. IL-2, 4 and 9. The current study describes the immunosuppressive effects of CP-690550, a novel, small molecule inhibitor of JAK-3, in a murine model of allergic pulmonary inflammation. In vitro, CP-690550 potently inhibited IL-4 induced upregulation of CD23 (IC(50)=57 nM) and class II major histocompatibility complex (MHCII) expression (IC(50)=71 nM) on murine B cells. Repeat aerosol exposure to ovalbumin in wild-type mice sensitized to the antigen resulted in preferential recruitment of Th2-like cells (IL-4+ and IL-5+) into bronchoalveolar lavage fluid (BAL). The importance of IL-4 in the development of pulmonary eosinophilia was supported by a marked (90%) reduction in the influx of these cells in IL-4KO mice similarly sensitized and ovalbumin exposed. Animals dosed with CP-690550 (15 mg/kg/d) during the period of antigen sensitization and boost demonstrated marked reductions in BAL eosinophils and levels of IL-13 and eotaxin following ovalbumin aerosol exposure. The JAK-3 inhibitor (1.5-15 mg/kg/d) also effectively reduced the same parameters when administered during the period of antigen challenge. In contrast, the calcineurin inhibitor tacrolimus (10 mg/kg) was effective only when administered during the period of ovalbumin aerosol exposure. These data support the participation of JAK-3 in processes that contribute to pulmonary eosinophilia in the allergic mouse model. CP-690550 represents an intriguing novel therapy for treatment of allergic conditions associated with airway eosinophilia including asthma and rhinitis.

FK506 aerosol locally inhibits antigen-induced airway inflammation in Guinea pigs

BACKGROUND

Eosinophilic airway inflammation is a common pathological feature of asthma. It has been shown that FK506 given systemically suppresses antigen-induced airway inflammation in animal models. However, it is unknown whether inhaled FK506 can suppress the airway allergic inflammation/immune response and whether it acts locally or systemically.

METHODS

We tested the effects of oral FK506 and inhaled FK506 on antigen-induced airway inflammation in guinea pigs. The tissue and blood concentrations of FK506 given via both routes were compared. The effect of inhaled FK506 on the expression of cytokine mRNA in lung and bronchoalveolar lavage fluid (BALF) cells was also tested.

RESULTS

Both routes of administration of FK506 suppressed the airway eosinophilia in egg albumin (EA)-sensitized and -challenged animals. The effect of three inhaled puffs was almost equal to that of 1 mg/kg administered by the oral route. Following inhalation of three puffs, FK506 concentration in blood (AUC(0-24 h)) was approximately 1/21 of that following oral FK506 (1 mg/kg). After EA challenge, mRNA expression of interleukin (IL)-5, eotaxin and IL-1beta in BALF cells and IL-5 in the lung increased significantly. FK506 aerosol markedly inhibited IL-5 mRNA expression in the lung. In situ hybridization indicated that in the BALF IL-5 mRNA expression by lymphocyte-like cells was inhibited by FK506 aerosol. In addition, anti-IL-5 antibody injected intratracheally almost completely abolished eosinophilia in this model.

CONCLUSION

Inhaled FK506 can suppress airway inflammation in guinea pigs, where the local action, presumably the inhibition of T-cell activation/function in the lung and airways, was primarily important.

Attenuation of the allergen-induced late asthmatic reaction by cyclosporin A is associated with inhibition of bronchial eosinophils, interleukin-5, granulocyte macrophage colony-stimulating factor, and eotaxin

The allergen-induced late asthmatic reaction (LAR) is associated with increases in bronchial eosinophils and basophils as well as upregulation of several eosinophil active cytokines and C-C chemokines. Cyclosporin A (CsA) was previously shown to inhibit the LAR, but not the early asthmatic reaction (EAR), and this was associated with a decrease in blood eosinophils. For these reasons, we determined whether CsA inhibited the allergen-induced increases in bronchial eosinophils, basophils, eotaxin, interleukin-5 (IL-5), and granulocyte macrophage colony-stimulating factor (GM-CSF). Subjects with a demonstrable LAR underwent bronchoscopy with biopsy and bronchoalveolar lavage (BAL) at baseline and then were randomly allocated to receive either CsA (n = 13) or placebo (n = 11) before challenge. A second bronchoscopy was performed 24 h later. The LAR, but not the EAR, was significantly attenuated in the CsA group compared with placebo (p < 0.05). CsA significantly inhibited the allergen-induced increases in IL-5 (p = 0.02) and GM-CSF (p = 0. 0028) in mRNA+ cells in BAL, and in a mAB against human activated eosinophils (EG2+) (p = 0.0227). We conclude that inhibition of the LAR by CsA may be related to its inhibitory effects on eosinophil-associated cytokines and chemokines. The beneficial effect of CsA in asthma may also be the result of inhibition of eosinophil accumulation.

Allergen-induced bronchial eosinophilia in guinea-pigs is inhibited by both pre- and post-induction cyclosporin-A treatments

Repeated treatment of sensitized guinea-pigs with cyclosporin-A (CS-A) before aerosol allergen challenge is known to inhibit the subsequent bronchial eosinophilia. It is not known, however, if the drug is also effective on established/on-going bronchial eosinophilia. We have, therefore, studied the effect of CS-A on allergen-induced eosinophil recruitment into the bronchoalveolar lavage (BAL) fluid of guinea-pigs when given before or after induction.Ovalbumin-immunized guinea-pigs were treated with CS-A (20 mg/kg subcutaneously) or vehicle daily for varying periods before a single aerosol allergen challenge. In animals in which bronchial eosinophilia was maintained with repeated aerosol allergen challenge, CS-A or vehicle was given daily for varying periods after the first allergen challenge. BAL and cell count were performed 24 h after the last challenge. In vehicle-treated animals, a single allergen challenge caused a 4-5 fold increase in the number of eosinophils in the BAL fluid after 24 h, declining to baseline by 7 days. In repeatedly-challenged animals, this response was sustained throughout. Eosinophil infiltration was significantly inhibited when CS-A was given daily for 7-14 days, but not for 1 or 3 days, before allergen challenge. When given during an established/on-going eosinophil infiltration, a significant inhibition was seen after administration for 5 or 7 days, but not for 1 or 3 days.These results show that repeated CS-A administration inhibits not only the induction of allergic bronchial eosinophilia but also the maintenance of an established one. This may be relevant in the treatment of allergic diseases, such as asthma, in which drug administration often begins when eosinophilia is already established.

Differential regulation of cytokine expression after allergen exposure of sensitized rats by cyclosporin A and corticosteroids: relationship to bronchial hyperresponsiveness

BACKGROUND

Cyclosporin A and dexamethasone exhibit different effects on allergic airway eosinophilia and bronchial hyperresponsiveness (BHR).

OBJECTIVE

We determined whether these were related to alteration of cytokine expression, particularly with regard to the profile of Th1- versus Th2-derived cytokines.

METHODS

Brown-Norway rats sensitized with ovalbumin were administered cyclosporine or dexamethasone before ovalbumin aerosol challenge. Bronchial responsiveness was measured 18 to 24 hours after aerosol exposure. Airway cellular influx was determined by bronchoalveolar lavage and tissue immunohistochemistry. The expression of Th1 and Th2 cytokine messenger RNA (mRNA) was analyzed by reverse transcriptase-PCR.

RESULTS

Ovalbumin exposure induced significant BHR, with increases in eosinophils, lymphocytes, and neutrophils in bronchoalveolar lavage fluid and an increase in eosinophils, CD2(+) and CD8(+), but not CD4(+) T cells, in the airway submucosa. IL-2, IFN-gamma, IL-4, and IL-5 mRNA expression in the lungs of sensitized ovalbumin-exposed rats was increased (P <.05) compared with controls. Cyclosporin A had no significant effect on BHR and neutrophil accumulation but reduced the number of bronchoalveolar lavage eosinophils (P <.002), airway submucosal eosinophils, and CD4(+) and CD8(+) T cells (P <.02). It also suppressed the induced mRNA expression of IL-2, IL-4, IL-5, and IFN-gamma. By contrast, the inflammatory cell influx and mRNA expression for IL-2, IL-4, and IL-5, as well as BHR, were suppressed by dexamethasone. However, an increase in IL-10 and IFN-gamma mRNA expression was found.

CONCLUSION

The differential activities of cyclosporin A and dexamethasone on inflammatory cell influx, particularly neutrophils, or cytokine expression such as IL-10 and IFN-gamma may underlie their contrasting effects on BHR.

Facilitation of apoptosis by cyclosporins A and H, but not FK506 in mouse bronchial eosinophils

This study was undertaken to clarify whether or not binding to cyclophilin is a prerequisite for cyclosporin A-induced modulation of apoptotic cell death in eosinophils. Eosinophils were isolated from bronchoalveolar lavage fluid of mice challenged with inhaled allergen after sensitization. Apoptosis was determined by analysing the DNA content. At 72 h, 99% of the cells had died without addition of cytokines, whereas 55-60% of the cells survived in the presence of 10 U/ml recombinant murine interleukin 5 or recombinant murine granulocyte macrophage-colony stimulation factor (GM-CSF). Apoptotic cell death at 72 h in the presence of 10 U/ml interleukin 5 was increased by addition of cyclosporin H, an analogue of cyclosporin A without cyclophilin binding activity, in a concentration-dependent (0.3 to 3 microM) manner. The increase in apoptosis elicited by cyclosporin A and cyclosporin H took place also in the presence of 10 U/ml GM-CSF but to a lesser extent. There was a significant augmentation of apoptosis in eosinophils cultured in the presence of each cytokine for 72 h or longer. Tacrolimus (FK506) failed to augment apoptotic cell death. Thus, it is unlikely that binding of cyclosporin A to cyclophilin accounts for the increased apoptosis induced by cyclosporin A and its analogue in eosinophils. The increase in apoptosis induced by cyclosporin A, but not FK506, in activated eosinophils from the airways may be attributed to the anti-asthmatic effects of cyclosporin A.

The effects of TYB-2285 and its metabolites on lymphocyte responses in vitro

1. We examined the effects of TYB-2285 and its metabolites (TC-286 and TC-326) on antigen-induced lymphocyte proliferation, allogeneic mixed lymphocyte reaction (MLR) and mitogen-induced lymphocyte proliferation. 2. Splenic lymphocytes from C57BL/6 strain mice sensitized with human serum albumin were cultured with the antigen in the presence of TYB-2285 or its metabolites (10(-7)-10(-4) M). The lymphocyte proliferation enhanced by antigen was inhibited by TYB-2285 and its metabolites in a dose-dependent manner. 3. Splenic lymphocytes collected from C57BL/6 and Balb/C strain mice were cocultured in the presence of TYB-2285 and its metabolites (10(-7)-10(-4) M). Allogeneic MLR was inhibited by TYB-2285 and its metabolites in a dose-dependent manner. 4. Splenic lymphocytes from C47BL/6 strain mice were cultured with concanavalin A (Con A) in the presence of TYB-2285 and its metabolites (10(-7)-10(-4) M). TYB-2285 and its metabolites did not affect Con A-induced lymphocyte proliferation. Cyclosporin A showed an inhibitory effect on Con A-induced lymphocyte proliferation that was as strong as the inhibitory effect on antigen-induced lymphocyte proliferation and allogeneic MLR at a lower concentration.

Cyclosporin A and FK506 reduce interleukin-5 mRNA abundance by inhibiting gene transcription

The cytokine interleukin-5 (IL-5) selectively induces the proliferation, differentiation, and activation of mature eosinophils. The immunosuppressive agents cyclosporin A (CsA) and FK506 ameliorate the influx of eosinophils seen in allergic conditions such as asthma. We investigated the mechanisms controlling IL-5 messenger RNA (mRNA) expression in human T-lymphocytes in the presence of CsA or FK506. Fresh human peripheral blood mononuclear cells (PBMC); 7-day cultured PBMC, which represent a population of activated T-lymphocytes derived from PBMC; and the T-cell line HSB-2 were used. A novel polymerase chain reaction (PCR)-based nuclear run-on assay was employed to investigate the rate of IL-5 gene transcription. IL-5 mRNA degradation was measured by quantitative reverse transcriptase (RT)-PCR. CsA and FK506 strongly inhibited cellular IL-5 mRNA expression in response to phytohemagglutinin (PHA), or to phorbol myristate acetate (PMA), and/or calcium ionophore. Marked inhibition was observed in PBMC, 7-day cultured PBMC, and HSB-2 cells. Nuclear run-on assays done with either 7-day cultured PBMC or HSB-2 cells demonstrated striking inhibition of IL-5 gene transcription by both CsA and FK506 at levels reflecting the degree of reduction of total cellular IL-5 mRNA abundance. Neither CsA or FK506 had any detectable effect on the stability of IL-5 mRNA. Thus, the inhibitory effect of CsA and FK506 on cellular IL-5 mRNA expression can be explained by inhibition of the rate of IL-5 gene transcription.

Parainfluenza virus type-3 infection attenuates the respiratory effects of antigen challenge in sensitized guinea pigs

Respiratory viral infections not only exacerbate asthma symptoms but may also be important in the pathogenesis of the disease. We therefore explored the effects of respiratory viral infection on the respiratory response of sensitized guinea pigs to antigen challenge. Lung tissue obtained from uninfected guinea pigs sensitized to ovalbumin aerosol released histamine upon incubation with the antigen in vitro. After antigen challenge in vivo, sensitized animals had significantly greater numbers of eosinophils in their bronchoalveolar lavage fluid than did nonsensitized animals and exhibited airway hyperresponsiveness to methacholine aerosol. When ovalbumin sensitization was initiated 7 days after inoculation with parainfluenza virus type-3 (PI-3), antigen challenge elicited little histamine release from infected lung tissue in vitro. Likewise, subsequent to antigen challenge in vivo, animals failed to exhibit airway hyperresponsiveness or an increased eosinophil population in bronchoalveolar lavage fluid. Similar effects were observed when sensitization was begun 19 days after PI-3 virus inoculation. The mechanism(s) responsible for the attenuated responses to antigen in PI-3 infected animals are unknown but may involve virus-induced effects on immune cells.

Down-regulation of Th2 cell-mediated murine peritoneal eosinophilia by antiallergic agents

Local eosinophilia has been linked to the pathogenesis of the inflammatory aspect of allergic diseases. The present study found that co-injection of D10G4.1 (D10) cells, a murine Th2 clone, with conalbumin (CA) into the peritoneal cavity of AKR/J mice increased the number of peritoneal eosinophils. The accumulation of eosinophils reached a maximum level at 24 to 48 hr and was accompanied by a marked increase in the number of neutrophils and a minor increase in the number of mononuclear cells. D10-induced peritoneal eosinophilia was suppressed by administration of either anti-IL-4 and anti-IL-5 monoclonal antibodies in an additive manner or by cyclosporin A (CsA). Interestingly, suplatast tosilate (IPD-1151T), known to be antiallergic agent capable of suppressing IgE synthesis and chemical mediator release, but not disodium cromoglycate, selectively suppressed eosinophil accumulation. Taken together with the observation that CsA and IPD-1151T suppressed IL-4 and IL-5 production by CA-stimulated D10 cells in vitro, the present results strongly suggest that agents capable of down-regulating Th2 cell cytokine production may attenuate allergic inflammation by impairing the recruitment of eosinophils that is mediated by Th2 cells.

Tacrolimus. A review of its pharmacology, and therapeutic potential in hepatic and renal transplantation

Tacrolimus (FK 506) is a macrolide immunosuppressant which possesses similar but more potent immunosuppressant properties compared with cyclosporin, inhibiting cell-mediated and humoral immune responses. Like cyclosporin, tacrolimus demonstrates considerable interindividual variation in its pharmacokinetic profile. This has caused difficulty in defining the optimum dosage regimen and has highlighted the usefulness of therapeutic drug monitoring. Most clinical studies with tacrolimus have neither been published in their entirety nor subjected to extensive peer review; there is also a paucity of published randomised investigations of tacrolimus versus cyclosporin, particularly in renal transplantation. Despite these drawbacks, tacrolimus has shown notable efficacy as a rescue or primary immunosuppressant therapy when combined with corticosteroids in adult and paediatric recipients following liver or kidney transplantation. Indeed, graft salvage rates in patients experiencing rejection or drug-related toxicity were > or = 50%, although data in renal transplantation are limited. Compared with cyclosporin as a primary immunosuppressant, tacrolimus showed comparable or greater patient/graft survival rates in liver allograft recipients (where cost savings associated with reduced hospitalisation costs were evident in one study), and comparable patient/graft survival in patients following kidney transplantation. Worthy of note was the efficacy of tacrolimus as a primary immunosuppressant in patients who received en bloc kidney allografts. The incidence of rejection was largely reduced following rescue therapy with tacrolimus and was generally lower (notably for refractory rejection) than that observed for cyclosporin, at least in liver allograft recipients. This was reflected in less need for adjunct immunotherapy including antilymphocyte preparations for the treatment of rejection episodes. The potential for reduction or withdrawal of corticosteroid therapy with tacrolimus appears to be a distinct advantage compared with cyclosporin, and this may be enhanced by the reduced incidence of infectious complications and of hypertension and hypercholesterolaemia reported by some investigators. In other respects, however, the tolerability profile of tacrolimus appears to be broadly similar to that of cyclosporin. Against this background, preliminary data indicate that tacrolimus provides a valuable therapeutic alternative to retransplantation in patients experiencing liver or kidney graft rejection or drug-related toxicity. Pending confirmation of initial randomised studies and preliminary results from large randomised investigations, tacrolimus may well be considered as an alternative primary immunosuppressant to cyclosporin in hepatic (particularly) and renal transplantation. Furthermore, the steroid-sparing effects of tacrolimus, although of benefit to all patient groups, may prove to be of particular worth in children and in en bloc kidney recipients. In these patients tacrolimus may well emerge as the drug of choice.(ABSTRACT TRUNCATED AT 400 WORDS)