Akihide Koda

Suppression of IgE production by IPD-1151T (suplatast tosilate), a new dimethylsulfonium agent: (1). Regulation of murine IgE response.

The effect of IPD-1151T, a new dimethylsulfonium compound, on the IgE response was investigated in the mouse system. The oral administration of IPD-1151T to immunized BALB/c mice suppressed the primary IgE antibody response and depressed the elevation of serum IgE levels, whereas the same treatment did not affect the IgG antibody response. The enhanced expression of low-affinity IgE receptor (Fc epsilon RII/CD23) on the spleen cells of immunized mice was also inhibited by IPD-1151T administration. It was further demonstrated from the adoptive transfer experiment that IPD-1151T, administered to hapten-primed B cell donors, but not to carrier-primed T cell donors, exerted its suppressive influence on the hapten-specific secondary IgE antibody response in irradiated syngeneic recipients. Interestingly, IPD-1151T concentration-dependently inhibited the production of interleukin 4 (IL-4) by D10G4.1, known to be a typical Th2 clone. However, IPD-1151T did not suppress the production of IgE and IgG1 by normal splenic B cells stimulated with lipopolysaccharide and IL-4. Moreover, IL-4-induced expression of Fc epsilon RII on normal spleen cells was not inhibited by the agent. These results strongly suggest that the IgE-suppressive activity of IPD-1151T is most likely due to the inhibition of IL-4 production at the T cell level.

Bleomycin-Induced Pulmonary Fibrosis in Genetically Mast Cell-Deficient WBB6F1-W/Wv Mice and Mechanism of the Suppressive Effect of Tranilast, an Antiallergic Drug Inhibiting Mediator Release from Mast Cells, on Fibrosis

It has been well known that the number of mast cells increases during the development of fibrosis in various tissues including the lung. However, the role of mast cells in fibrosis still remains obscure. In the present paper, we evidenced that pulmonary fibrosis could be induced in genetically mast cell-deficient WBB6F1-W/Wv mice as well as WBB6F1-(+/+) mice having mast cells normally by the treatment with bleomycin (BLM, 5 mg/kg, i.v., 10 days), and there was not much difference in the histological changes of lungs between the two strains. An increase in the hydroxyproline content of the lung of WBB6F1-W/Wv mice was rather higher than that of WBB6F1-(+/+) mice. Previously, we reported that tranilast, an antiallergic drug inhibiting chemical mediator release from mast cells, suppressed the development of BLM-induced pulmonary fibrosis in ICR mice, suggesting the possibility that mast cells play certain roles in fibrosis. However, it was evidenced in the present report that tranilast suppressed BLM-induced fibrosis in WBB6F1-W/Wv mice. Tranilast neither suppressed the cytotoxic activity of BLM against KB cells and L-929 cells in vitro, nor inhibited the antitumor activity of BLM against Sarcoma-180 transplanted subcutaneously into ICR mice. Tranilast may act through suppressing BLM-induced activation of lymphoid cells including macrophage and neutrophil. These results indicate an inconsequential role of mast cells in the development of fibrosis. Increases in the number of mast cells and in histamine content of the lung, which were widely reported in the lungs of BLM-treated mice, may be the result of fibrosis.

Effect of murine recombinant interleukin‐5 on the cell population in guinea‐pig airways

1 An intratracheal injection of murine recombinant interleukin 5 (mrIL‐5, 2–15 μg/0.25 ml/animal) induced a dose‐dependent increase in the number of macrophages, eosinophils, neutrophils and epithelial cells in the bronchoalveolar lavage fluid (BALF) of guinea‐pigs 24 h after administration. Bovine serum albumin (15 μg/0.25 ml/animal), used as a reference material, did not cause any change of this type. 2 The intratracheal administration of mrIL‐5 at a dose of 15 μg showed a tendency to increase the number of these pulmonary inflammatory cells and epithelial cells in the BALF at 12 h with a significant increase observed at 24 h. 3 Prednisolone (20 mg kg−1, i.p.) inhibited the mrIL‐5‐induced increase in macrophages, eosinophils, neutrophils and epithelial cells. Ketotifen (2 mg kg−1, i.p.) reduced the mrIL‐5‐induced increase in the eosinophil, neutrophil and epithelial cell populations. The simultaneous injection of 2% disodium cromoglycate (DSCG) into the trachea prevented the mrIL‐5‐induced increase in the number of airway epithelial cells, without affecting changes in the other inflammatory leukocytes. 4 These results suggest that mrIL‐5 is a potent inducer of lung inflammation, in terms of increased inflammatory leukocytes and epithelial cells in guinea‐pig BALF. Prednisolone, DSCG and ketotifen are effective against mrIL‐5‐induced pulmonary inflammation, especially the desquamation of bronchial epithelial cells.

Effect of murine recombinant interleukin-5 on bronchial reactivity in guinea-pigs

We have reported that an intratracheal injection of murine recombinant interleukin‐5 (mrIL‐5, 15 μg/0.0 ml/animal) induces the increased number of inflammatory leucocytes and epithelial cells in bronchoaiveolar lavage fluid (BALF) 24 hr after administration of mrIL‐5 in guinea‐pigs [1]. In this paper, we have examined the effects of mrIL‐5 on bronchial reactivity in guinea‐pigs. An intratracheal injection of mrIL‐5 (15 μg/0.0 ml/animal) induced airway hyperresponsiveness to acetytcholine (ACh) which was accompanied with eosinophilia and neutrophilia in blood at 24 hr in guinea‐pigs. Bovine serum albumin (BSA, 15 μg/0.0 ml/animal) used as a reference material did not cause airway hyperresponsiveness, blood eosinophilia and neutrophilia. Prednisotone (20 mg/kg, i.p.) inhibited mrIL‐5‐induccd airway hyperresponsiveness, eosinophilia and neutrophilia. Ketotifen (2 mg/kg, i.p.) also reduced this airway hyperresponsiveness and neutrophilia but not eosinophilia. In contrast, the injection of 2% disodium cromoglycale (DSCG) into the trachea showed the tendency of inhibitory effects against mrIL‐5‐induced airway hyperresponsiveness, eosinophilia and neutrophilia. The present data indicate that mrIL‐5 induces airway hyperresponsiveness, blood eosinophilia and neutrophilia in guinea‐pigs and that prednisolone and ketotifen inhibit mrIL‐5‐induced airway hyperresponsiveness accompanied with reduction of the increased number of leucocytes, suggesting that eosinophils and neutrophilia in blood may be important for the onset of bronchial hyperresponsiveness caused by mrIL‐5 in guinea‐pigs.

Astilbin selectively induces dysfunction of liver-infiltrating cells — novel protection from liver damage

The present study aimed to examine the effect of astilbin, a flavanoid, on liver injury. When administered during the effector but not induction phase, astilbin significantly decreased the liver injury induced by delayed-type hypersensitivity to picryl chloride in mice. The pretreatment of nonparenchymal cells but not hepatocytes with astilbin in vitro caused a concentration- and time-dependent inhibition against the damage. Nonparenchymal cells isolated from astilbin-administered mice also showed a significant incompetence of hepatotoxicity, correlated with the inhibition of serum transaminase elevation. However, astilbin did not protect from CCl4-induced liver damage. Furthermore, the flavanoid markedly promoted the apoptosis of nonparenchymal cells from liver-injured mice, whereas did not influence those from naive mice. These results suggest that astilbin provides improvement against liver injury through a selective dysfunction of liver-infiltrating cells rather than by protecting the hepatocyte membrane. Such characteristics will be of significance to pave a new way for treating immunologically related liver diseases and for developing new drugs.

Studies on Vascular Permeability Increasing Factors Involved in 48-Hour Homologous PCA in the Mouse Ear

Several attempts were made to elucidate the possible role of histamine, serotonin, leukotrienes C4 (LTC4) and D4 (LTD4), and prostaglandin E1 (PGE1) as vascular permeability increasing factors involved in 48-hour homologous passive cutaneous anaphylaxis (PCA) in the mouse ear. Increased vascular permeability in the mouse ear caused by the mediator injection or PCA was assessed quantitatively by measuring the amount of extravasated dye. In skin reactions, all of the mediators used in the present study significantly increased vascular permeability. The most potent mediator was serotonin, which increased the vascular permeability from a concentration of 10(-8) g/ml, and the activity was about 100 times higher than that of histamine on a weight basis. Vascular permeability increasing activity of LTC4 was about 10 times higher than that of histamine, and LTD4 and PGE1 were also more potent than histamine. Increases of vascular permeability caused by histamine, serotonin, LTC4 and LTD4 were significantly potentiated by injecting 10(-6) g/ml of PGE1 simultaneously. Histamine-, serotonin- and LTC4-induced skin reactions in the mouse ear were suppressed significantly by the administrations of chlorpheniramine, methysergide and FPL 55712, respectively. In contrast, though chlorpheniramine and methysergide suppressed also mouse ear PCA (about 50 and 40%, respectively), neither FPL 55712, indomethacin nor BW 755C suppressed it. These results strongly suggest that the most important mediator involved in mouse ear PCA is histamine and that serotonin also plays an important role in the increase of vascular permeability caused by PCA. Despite their potent vascular permeability increasing activity LTC4, LTD4 and PGE1 do not seem to play an important role in mouse ear PCA.

Homologous Passive Cutaneous Anaphylaxis in Various Strains of Mice

Passive cutaneous anaphylaxis (PCA) was elicited both in the ear and in the dorsal skin of 13 strains of mice at the same time and assessed quantitatively by measuring the amount of extravasated dye. Body pigments of colored mice such as DBA/2 (chocolate), C3H/He (brown) and C57BL/6 (black) did not interfere with the measurement of dye. In the ear response, ICR was a higher responder, C57BL/6 and BALB/c-nu/nu were lower responder strains. In the dorsal skin response, however, ICR was a lower responder, BALB/c-nu/nu, Hairless and WBB6F1-+/+ were higher responders. WBB6 F1-W/Wv was a nonresponder in both responses. The ear response was highly reproducible and the dorsal skin response of each strain was 1/2-1/10 of its ear response except for BALB/c-nu/nu. The PCA bluing regions on the dorsal skin of BALB/c-nu/nu were clearly delineated and the response was almost comparable to its ear response.

A Method for Evaluating Anti-Allergic Drugs by Simultaneously Induced Passive Cutaneous Anaphylaxis and Mediator Cutaneous Reactions

Homologous passive cutaneous anaphylaxis (PCA) was induced by IgE antibody and, simultaneously, cutaneous reactions were induced by some allergic mediators such as histamine, serotonin and leukotriene (LT) C4 on rat back skin. Disodium cromoglycate and tranilast with inhibitory actions on mediator release inhibited PCA specifically, whereas antihistaminics, including ketotifen, azelastine, mequitazine and diphenhydramine, inhibited histamine- and serotonin-induced cutaneous reactions as well as PCA. Anti-slow-reacting substance of anaphylaxis drugs, KC-404 and FPL-55712, significantly inhibited PCA and histamine- and serotonin-induced reactions, but at the same doses they did not produce significant inhibition of the LTC4-induced reaction. All reactions tested were strongly inhibited dose dependently with the beta stimulants, salbutamol and isoproterenol, and a xanthine derivative, theophylline, which are known to increase the intracellular cyclic AMP level. We think that this method enables the determination of the properties of anti-allergic drugs.

Mouse Ear PCA as a Model for Evaluating Antianaphylactic Agents

Passive cutaneous anaphylaxis (PCA) reaction elicited in ears of male ddY mice was studied by means of assessing dye leakage. In the ear, PCA reaction was more sensitive and reproducible than that in the dorsal skin. The reaction was significantly suppressed by ketotifen, one of antianaphylactic agents.

Inhibitory Effects of β-Adrenergic Stimulants on Increased Vascular Permeability Caused by Passive Cutaneous Anaphylaxis, Allergic Mediators, and Mediator Releasers in Rats

The effects of isoproterenol, salbutamol, theophylline, and forskolin on IgE antibody-mediated homologous passive cutaneous anaphylaxis (PCA) and on skin reactions caused by allergic mediators and mediator releasers were investigated in rats. Isoproterenol and salbutamol dose-dependently inhibited the PCA and skin reactions caused by histamine, serotonin, and leukotriene C4 (LTC4), elicited at the same time in the same rat. These agents also dose-dependently inhibited the skin reactions caused by platelet-activating factor (PAF), leukotriene D4 (LTD4), compound 48/80 (48/80), and calcium ionophore A23187 (A23187). Propranolol overcame the inhibitory effect of isoproterenol on PCA and skin reactions in a dose-dependent manner. Theophylline and forskolin showed similar effects as the beta-adrenergic stimulants. These results indicate that beta-adrenergic stimulants inhibit the increased vascular permeability caused by allergic mediators, and suggest that this activity of beta-adrenergic stimulants might play an important role in their antiallergic actions. Inhibition of increased vascular permeability might be mediated via beta-receptors and may be related to the increase in intracellular cyclic AMP levels.