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Atsuki Fukushima

Publications and source records attributed to Atsuki Fukushima.

At least 19 recordsLinked to original sources
PubMed2006

Antibodies to T-cell Ig and mucin domain-containing proteins (Tim)-1 and -3 suppress the induction and progression of murine allergic conjunctivitis.

The T cell Ig and mucin domain-containing proteins (Tim) regulate Th1- and Th2-mediated immune responses. We investigated the ability of Abs blocking Tim-1 or Tim-3 ligand-binding activity to prevent and treat murine experimental allergic conjunctivitis (EC), a Th2-mediated disease. Treatment with either Ab during the induction phase of EC in actively immunized wild-type mice suppressed EC and upregulated Th1 and Th2 immune responses. In contrast, both Abs exacerbated EC in actively immunized IFN-gamma-knockout mice. Thus, both anti-Tim Abs suppress the pathogenic immune responses generated in the induction phase by upregulating systemic IFN-gamma production. Treatment of actively immunized mice and passively immunized mice with either anti-Tim Ab just prior to RW challenge also suppressed EC. Thus, treatment with anti-Tim-1 or anti-Tim-3 Ab can suppress both the induction and progression of EC, which could indicate potential preventive and/or therapeutic approaches for allergic diseases such as allergic conjunctivitis.

Animals↗
PubMed2006

Differential contributions of B7-1 and B7-2 to the development of murine experimental allergic conjunctivitis.

B7-1 and B7-2 are the co-stimulatory molecules that are involved in activation of T cells. We investigated whether B7-1 and B7-2 play a role in the development of T cell-mediated experimental allergic conjunctivitis (EC). EC was induced in Balb/c mice by active immunization with ragweed (RW) followed by RW challenge in eye drops. These mice were treated with neutralizing anti-B7-1 Ab, anti-B7-2 Ab, both Abs, anti-cytotoxic T lymphocyte-associated Ag-4 (CTLA-4) Ab or normal IgGs as controls either during the induction phase or the effector phase. With regard to the induction phase treatment, EC was significantly attenuated when both anti-B7-1 and anti-B7-2 Abs were injected. In contrast, anti-CTLA-4 Ab treatment significantly exacerbated EC. With regard to the effector phase treatment, anti-B7-2 Ab alone significantly attenuated EC, while anti-CTLA-4 Ab tended to exacerbate EC. Collectively, B7-1 and B7-2 differently contribute to the development of EC during the induction and effector phases.

Animals↗
PubMed2006

Roles of CD4+CD25+ T cells in the development of experimental murine allergic conjunctivitis.

BACKGROUND: CD25+ regulatory T (T reg) cells play a suppressive role in experimental autoimmune uveoretinitis as well as experimental airway inflammation but their involvement in the development of allergic conjunctivitis (AC) remains unclear. We therefore investigated whether T reg cells play a role in the development of experimental AC (EC). METHODS: BALB/c and C57BL/6 mice were actively immunized with ragweed (RW). The mice were treated with an anti-CD25 Ab (PC61) or control normal rat IgG (nrIgG) either 2 days prior to active immunization or during the induction phase (days 0, 2, 4, 6 and 8). Ten days after active immunization, the mice were challenged with RW-containing drops. Twenty-four hours after the challenge, the conjunctivas were harvested for histological analysis of eosinophil infiltration, and the spleens were harvested for cell culture for splenocyte transfer. Cultured splenocytes were transferred into syngeneic mice, and 4 days after the transfer, the recipient mice were challenged with RW. Twenty-four hours after the challenge, conjunctivas were collected for histological analysis. RESULTS: Pretreatment with PC61 did not affect EC in either strain of mice; however, treatment with PC61 during the induction phase significantly suppressed EC in C57BL/6 mice. In contrast, transfer of RW-primed splenocytes from mice treated with PC61 induced EC that was significantly more severe regardless of strain and treatment protocol. CONCLUSIONS: The finding that T reg cells play a suppressive role in the development of EC in splenocyte transfer experiments suggests that modulation of T reg cells may be a possible therapy for AC.

Adoptive Transfer↗
PubMed2006

Analysis of the interaction between IFN-gamma and IFN-gammaR in the effector phase of experimental murine allergic conjunctivitis.

IFN-gamma acts to promote the severity of experimental allergic conjunctivitis (EC) during the effector phase. To identify the cell source and cell target of this cytokine in the effector phase of EC, we established mice lacking both IFN-gamma and the IFN-gamma receptor (Dbl-KO). Reciprocal adoptive transfer experiments involving wild-type, Dbl-KO, IFN-gamma-lacking and IFN-gammaR-lacking mice were performed. EC was then induced by RW challenge in eye drops. Analysis of the resulting eosinophil infiltration in the six donor/recipient combinations revealed that IFN-gamma produced by both donor and recipient cells plays an important role in the EC effector phase, and that the targets for this cytokine are also both donor and recipient cells. That EC was attenuated when any of the IFN-gamma-IFN-gammaR interactions were disturbed confirms that IFN-gamma promotes the severity of EC during the effector phase. These observations indicate that Dbl-KO mice will be useful for investigating the role(s) IFN-gamma play in inflammatory diseases.

Adoptive Transfer↗
PubMed2006

Modulation of murine experimental allergic conjunctivitis by treatment with alpha-galactosylceramide.

When mice are treated with alpha-galactosylceramide (alpha-GalCer), NKT cells are activated and suppress the development of experimental airway inflammation. This suppressive effect is believed to be mediated by the upregulation of IFN-gamma. Here, we investigated whether alpha-GalCer treatment can also modulate the development of experimental allergic conjunctivitis (EC). EC was induced in wild-type and IFN-gamma-deficient Balb/c mice by active immunization with ragweed (RW) followed by challenge with RW in eye drops. The mice were intraperitoneally injected with alpha-GalCer or vehicle at the time of immunization or before RW challenge. Twenty-four hours after RW challenge, conjunctivas, spleens and sera were harvested for histological analysis, flow cytometric, proliferation and cytokine assays, and measurement of immunoglobulin levels, respectively. Treatment with alpha-GalCer at the time of the EC-priming immunization significantly increased Th2 responses and markedly upregulated the severity of the EC. However, treatment with alpha-GalCer just before the Ag challenge that triggers EC in primed animals significantly suppressed the disease. This was associated with an increased frequency of CD4(+)CD25(+) cells, which express Foxp3, in the spleen. alpha-GalCer treatment just prior to Ag challenge also suppressed the development of EC in IFN-gamma-deficient mice, and we found apoptosis and anergy are unlikely to play a major role in the mechanism by which pre-challenge alpha-GalCer treatment suppresses EC. These data suggest that NKT cells can play a downregulatory role in the development of EC and that alpha-GalCer may be useful for treating allergic conjunctivitis.

Allergens↗
PubMed2006

Role of VLA-4 in the development of allergic conjunctivitis in mice.

PURPOSE: The severity of allergic conjunctivitis (AC) correlates with the degree of eosinophil infiltration into the conjunctiva, which is believed to be mediated by chemokines and adhesion molecules. The adhesion molecule very late antigen (VLA)-4 and its ligand, vascular cell adhesion molecule (VCAM)-1, are known to play important roles in eosinophil infiltration. However, the expression and function of VLA-4 in AC have not been investigated in detail. We sought to characterize VLA-4-expressing cells in the conjunctivas of mice that are developing experimental AC (EC) and to determine whether the interaction between VLA-4 and VCAM-1 is needed for the infiltration of eosinophils into the conjunctiva in AC. METHODS: EC was induced in Balb/c mice by active immunization with ragweed (RW) or adoptive transfer of RW-primed splenocytes, followed by RW challenge. Twenty-four hours after RW challenge, the conjunctivas were harvested. The conjunctivas from naive mice or mice developing EC were evaluated for VLA-4 and VCAM-1 expression by immunohistochemistry and immunofluorescent analyses. To investigate whether the interaction between VLA-4 and VCAM-1 is needed for the genesis of AC, mice developing EC were treated with anti-VLA-4 or anti-VCAM-1 antibodies two h before and after RW challenge. As a control, EC-developing mice were treated with normal rat IgG. Twenty-four hours after RW challenge, the conjunctivas were harvested for histological analysis. RESULTS: Upon induction of EC, VLA-4-expressing cells infiltrated the conjunctiva but the constitutive VCAM-1 expression around conjunctival vessels was not augmented. Immunofluorescent analyses demonstrated that most of the T cells infiltrating the conjunctiva expressed VLA-4 but only half of the infiltrating eosinophils expressed it. Treatment with both anti-VLA-4 and anti-VCAM-1 antibodies significantly suppressed the infiltration of eosinophils into the conjunctiva that was induced by either active immunization or splenocyte transfer. CONCLUSIONS: These results confirm that VLA-4-expressing cells infiltrate the conjunctiva and that the interaction between VLA-4 and VCAM-1 is needed for the development of EC.

Adoptive Transfer↗
PubMed2006

Pharmacokinetic analysis of platelet-activating factor in the tears of guinea pigs with allergic conjunctivitis.

PURPOSE: The aim of this study was to examine the levels of platelet-activating factor (PAF) and lyso-PAF in tears from experimental animals developing allergic conjunctivitis (AC). METHODS: AC was induced in guinea pigs by application of ovalbumin in eye drops. Tear samples were collected from 5 actively sensitized animals and from 5 unsensitized control animals before the challenge, and 1, 2, 4, and 6 h postchallenge. C18:0-PAF, C18:0-lyso-PAF, C16:0-PAF, and C16:0-lyso-PAF levels in the tear samples were determined using liquid chromatography-tandem mass spectrometry. RESULTS: The concentrations of C16:0-PAF, C16:0-lyso-PAF, and C18:0-lyso-PAF were measurable in both unsensitized and sensitized groups, whereas C18:0-PAF was undetectable in tear samples from either group. The levels of C16:0-PAF, C16:0-lyso-PAF, and C18:0-lyso-PAF in sensitized animals increased throughout the time course of the experiment, whereas there was no corresponding increase in the levels of these molecules in the unsensitized group. There were strong correlations between the concentrations of C16:0-PAF and C16:0-lyso-PAF, both in the sensitized and in the unsensitized group, and the concentrations of C16:0-lyso-PAF and C18:0-lyso-PAF within each group. CONCLUSIONS: The data from this study demonstrated that the levels of PAF and lyso-PAF increase in tears in a guinea pig model of AC development and implicate a role for PAF for the development of AC.

Animals↗
PubMed2006

Role of suppressor of cytokine signaling in ocular allergy.

PURPOSE OF REVIEW: The goal of this article is to evaluate developments in the knowledge of suppressor of cytokine signaling (SOCS) protein ocular allergy and the potential of SOCS proteins as targets for therapeutic strategies. RECENT FINDINGS: The family of proteins designated SOCS proteins plays an important role in Th2-mediated allergic responses through the control of the balance between Th1 and Th2 cells. SOCS3 and SOCS5 are predominantly expressed in Th2 and Th1 cells, respectively, and they reciprocally inhibit the Th1 and Th2 differentiation processes. SOCS3 is highly expressed at the disease site of allergic conjunctivitis, and T-cell-specific expression of SOCS3 deteriorates clinical and pathological features of allergic conjunctivitis. Reduction of the expression level or inhibition of function clearly reduces the severity of allergic conjunctivitis. On the other hand, constitutive expression of SOCS5, a specific inhibitor of IL-4 signaling, results in reduced eosinophil infiltration. Moreover, negative regulation of the Th2-mediated response by dominant-negative SOCS3 and SOCS5 reduced the incidence of allergic conjunctivitis in a mouse model. SUMMARY: The present article summarizes recent findings in terms of a role of SOCS protein as a negative regulator in ocular allergy and its clinical application.

Animals↗
PubMed2006

CD8+ T cells play disparate roles in the induction and the effector phases of murine experimental allergic conjunctivitis.

Although CD4+ Th2 cells clearly play an essential role in the development of experimental allergic diseases, the functions CD8+ T cells may have in these diseases have been investigated less extensively and remain controversial. Here, we investigated the roles of CD8+ T cells in the development of experimental allergic conjunctivitis (EC). EC was induced in CD8alpha-deficient (CD8KO) mice and wild-type (WT) mice by active immunization with short ragweed pollen (RW) followed by challenge with RW-containing eye drops. Alternatively, EC was induced by transferring RW-primed splenocytes followed by RW challenge. With regard to actively immunized mice, CD8KO mice showed significantly less severe eosinophil infiltration of the conjunctiva and lower total IgE levels, although the levels of the other Igs were equivalent between the two strains. Cytokine production by cultured splenocytes also did not differ, but the WT conjunctivas showed upregulated IL-5 and IL-6 expression and greater upregulation of IL-4 expression than the conjunctivas of CD8KO mice. Thus, CD8+ T cells may play a significant role during the induction phase by aiding IgE production and the generation of Th2 cytokines in the conjunctiva, thus promoting the development of EC. In contrast, splenocytes from CD8KO mice induced significantly more severe EC in WT mice than cells from WT mice. In addition, transfer of RW-primed splenocytes induced significantly more severe eosinophil infiltration in CD8KO recipient mice. Thus, CD8+ T cells promote the development of EC during the induction phase, but suppress it during the effector phase.

Adoptive Transfer↗
PubMed2006

Roles of OX40 in the development of murine experimental allergic conjunctivitis: exacerbation and attenuation by stimulation and blocking of OX40.

PURPOSE: To investigate the roles of interaction between OX40 and OX40 ligand (OX40L) in the development of experimental allergic conjunctivitis (EC) in mice. METHODS: BALB/c mice actively immunized with short ragweed pollen (RW) were intraperitoneally injected on days 0, 2, 4, 6, and 8 with agonistic anti-OX40 Ab, blocking anti-OX40L Ab, or normal rat (nr)IgG. On day 10, the mice were challenged with RW in eye drops, and 24 hours later their conjunctivas, spleens, and blood were harvested for analyses. For examination of the effects of the Abs during the late induction (or effector) phase, actively immunized mice were treated with the Abs just before or at the same time as the challenge. In addition, splenocytes from RW-primed mice were transferred into syngeneic naïve mice, and the recipients were treated with Abs twice (on days 2 and 4). On day 4, the mice were challenged with RW and evaluated. RESULTS: When the treatments were performed during the induction phase, anti-OX40 Ab treatment significantly increased clinical EC and eosinophil infiltration into the conjunctiva, whereas anti-OX40L Ab treatment significantly reduced eosinophil infiltration. Compared with splenocytes from nrIgG-treated mice, splenocytes from anti-OX40 Ab-treated mice proliferated vigorously against RW and produced significantly higher amounts of IL-2, -4, and -5 by RW stimulation but a significantly lesser amount of IFN-gamma after Con A stimulation. In contrast, splenocytes from anti-OX40L Ab-treated mice produced significantly less IL-5 with RW stimulation and IL-2 and IL-5 with Con A stimulation, whereas significantly more IFN-gamma was induced by Con A stimulation. Treatment with anti-OX40 and anti-OX40L Abs during the late induction or effector phase of EC did not affect eosinophil infiltration. CONCLUSIONS: Blocking of the interaction between OX40 and OX40L in vivo inhibits the development of EC. In contrast, forced stimulation of OX40 in vivo significantly exacerbates EC by activating T cells, especially Th2 cells. These effects were noted only in the induction phase of EC, suggesting that the interaction between OX40 and OX40L is important in the generation of Th2 immune responses in the development of EC.

Adoptive Transfer↗
PubMed2006

The early efficacy of topical levocabastine in patients with allergic conjunctivitis.

BACKGROUND: We investigated the early efficacy of topical levocabastine, an H(1) histamine-receptor antagonist, in improving the clinical symptoms of allergic conjunctivitis. METHODS: Thirty-six patients with allergic conjunctivitis were enrolled. One drop of levocabastine was instilled in one eye and one drop of artificial tears in the contralateral eye. Clinical examinations were performed before, and 15 and 30 minutes after instillation. Symptoms of itching and signs of injection were assessed at each time point. RESULTS: Both levocabastine and artificial tears resulted in a statistically significant reduction in ocular itching. However, levocabastine was significantly more effective. CONCLUSIONS: Although artificial tears had a positive effect in reducing symptoms of allergic conjunctivitis, by the washing out of allergens, levocabastine was more effective than artificial tears in controlling acute symptoms of allergic conjunctivitis, demonstrating that the selective H1 histamine-receptor antagonist action of levocabastine is rapidly effective in a clinical setting.

Administration, Topical↗
PubMed2005

TLR2 agonist ameliorates murine experimental allergic conjunctivitis by inducing CD4 positive T-cell apoptosis rather than by affecting the Th1/Th2 balance.

Innate immune responses that operate through Toll-like receptors (TLRs) are actively involved in the development of diseases predominantly mediated by adaptive immune responses. This is true also for allergic disease, as TLRs have been found to be involved in the development of allergic airway inflammation. We investigated whether stimulating TLR2 also abrogates murine allergic conjunctivitis by upregulating Th1 responses. We found that treating mice during the efferent phase with the TLR2 agonist Pam3CSK4 significantly suppressed eosinophil infiltration into the conjunctiva. However, Pam3CSK4 treatment inhibited both the Th1 and Th2 responses in the mice, and also suppressed eosinophil infiltration in IFN-gamma knockout mice. Flow cytometric analysis demonstrated that Pam3CSK4 treatment significantly elevated the numbers of annexin V-positive splenocytes, especially CD4 positive T cells. Thus, the stimulation of TLR2 during the efferent phase of murine allergic conjunctivitis suppresses eosinophil infiltration by inducing CD4 positive T-cell apoptosis rather than upregulating Th1 responses.

Animals↗
PubMed2005

The interaction between ICOS and B7RP-1 is not required for the development of experimental murine allergic conjunctivitis.

It is still unclear whether the interaction between inducible costimulator (ICOS) and its ligand, B7 related protein (B7RP)-1, is important for the development of allergic diseases. We investigated whether blocking the ICOS/B7RP-1 interaction affects the development of murine experimental allergic conjunctivitis (EC). EC was induced in Balb/c mice either by active immunization of ragweed (RW) or by transferring RW-primed splenocytes, followed by challenge with RW-containing eye drops. The mice were treated with anti-B7RP-1 antibody (Ab) or normal rat immunoglobulin G (IgG) during either the induction or effector phase. Regardless of the induction method or when the animals were treated, eosinophil infiltration into the conjunctiva was not affected by the anti-B7RP-1 Ab treatment. Splenocyte responses were not largely affected by this treatment. However, serum Ig levels were significantly reduced. These data suggest that blocking the ICOS/B7RP-1 in allergic diseases may not always be therapeutic.

Allergens↗
PubMed2005

Role of IL-27-producing dendritic [corrected] cells in Th1-immunity polarization in Lewis rats.

Lewis and Brown Norway rats are entirely different with respect to the polarization of their immune responses (Th1 and Th2, respectively). We found that naive Lewis rat splenocytes treated in vitro with heat-killed Mycobacterium tuberculosis (Mtb) upregulate the expression of both subunits of IL-27 (IL-27p28 and EBI3). Mtb treatment caused naive Lewis rat splenocytes to express 4.6-fold more IL-27p28 than Mtb-treated Brown Norway rat splenocytes 6h after the treatment. Although WSX-1, the IL-27 receptor, was not induced by Mtb treatment in splenocytes from either rat strain, Lewis rats expressed significantly higher levels of the IL-27 signal transducers T-bet and IL-12Rbeta2 than Brown Norway rats. Flow cytometric analysis of dendritic cells from bone marrow cells revealed Lewis rats had more IL-27p28-positive cells. Thus, early in the immune response, Lewis rats appear to produce higher levels of IL-27 than Brown Norway rats, resulting in polarization towards Th1-immunity.

Animals↗
PubMed2005

Lck couples Shc to TCR signaling.

Recent genetic evidence demonstrated that Shc is a critical molecule for T cell activation and differentiation. However, how Shc is coupled to the T cell antigen receptor (TCR) has not been clearly characterized. Here we report that the tyrosine kinase Lck functions as a connecting molecule for TCR and Shc. Lck plays a critical role in TCR signal transduction by phosphorylating the immuno-receptor tyrosine based activation motif (ITAM). Our data shows that the PTB domain of Shc binds the SH2/3 domains of Lck in a phosphotyrosine-independent manner. Inhibition of the Lck/Shc interaction led to the loss of IL-2 promoter activation, confirming that the role of Shc in IL-2 production requires its interaction with Lck. Together, the data show that Shc is connected to the activated TCR via direct interaction with Lck.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Fyn regulates eosinophil infiltration into the conjunctiva by downregulating the Th2 response.

PURPOSE: Under certain circumstances, fyn may serve to negatively regulate the differentiation of naïve helper T (Th) cells into Th2 cells. This study aimed to investigate whether fyn negatively regulates the development of experimental immune-mediated blepharoconjunctivitis (EC), in which Th2 cells play an important role in C57BL/6 mice. METHODS: C57BL/6 background wild-type (WT) or fyn knockout (fyn-/-) mice were subcutaneously immunized with ragweed (RW) adsorbed in aluminum hydroxide. Ten days later the mice were challenged with RW in eye drops, and 24 h after challenge, eyes, blood and spleens were harvested for histology, measurement of serum IgE, and proliferation or cytokine assays, respectively. RW-primed splenocytes from WT and fyn-/- mice were cultured in the presence of RW. Seventy-two hours later, either whole splenocytes or isolated CD4+T cells were transferred into syngeneic WT mice. Four days after the transfer, the recipient mice were challenged with RW and evaluated as described above. RESULTS: Infiltration of eosinophils into the conjunctiva induced by active immunization was significantly increased in fyn-/- mice relative to WT mice. Total serum IgE was also significantly higher in fyn-/- mice than in WT mice. In parallel, a higher level of IL-4 production from splenocytes was induced by concanavalin A stimulation in fyn-/- mice than in WT mice. In contrast to active immunization, transfer of whole splenocytes or separated CD4+T cells derived from WT or fyn-/- mice induced similar levels of eosinophilic infiltration in WT mice. CONCLUSIONS: Fyn regulates infiltration of eosinophils into the conjunctiva through downregulation of Th2 responses. This negative regulation is exerted only during the induction phase of EC.

Animals↗