Shigeru Takafuji

Adjuvant activity of diesel-exhaust particulates for the production of IgE antibody in mice

The prevalence rate of allergic rhinitis caused by pollen has strikingly increased in Japan in the last three decades. The number of diesel cars in use has also rapidly increased in the country. This fact urged us to study the effects of particulates emitted from diesel cars on the production of IgE antibody. The primary IgE antibody responses in mice immunized with intraperitoneal injection of ovalbumin (OA) mixed with diesel-exhaust particulates (DEP) were higher than those in the animals immunized with OA alone. This effect of DEP on the production of IgE antibody in mice was also demonstrated when mice were immunized with repeated injections of dinitrophenylated-OA. In addition, persistent IgE-antibody response to major allergen of Japanese cedar pollen (JCPA), a most common pollen causing allergic rhinitis in Japan, was observed in mice immunized with JCPA mixed with DEP but not in the animals immunized with JCPA alone. The results do indicate that the adjuvant activity of DEP can not be excluded as a possible cause of the associated change in the number of diesel cars and allergic rhinitis caused by pollen in Japan.

Diesel-exhaust particulates inoculated by the intranasal route have an adjuvant activity for IgE production in mice

Our previous study indicated that the IgE antibody responses in mice immunized with intraperitoneal injection of the antigens mixed with diesel-exhaust particulates (DEP) were higher than those in the animals immunized with the antigens alone. We examined the adjuvant activity of DEP inoculated by the intranasal route, i.e., the natural entrance of DEP. In 3-week interval immunization, the IgE antibody responses in mice immunized with intranasal inoculation of ovalbumin (OA) mixed with DEP were higher than responses in the animals immunized with OA alone. DEP had an adjuvant activity for anti-OA IgE antibody production, even in a small dose such as 1 micrograms administered with a 3-week interval. Also in 1-week interval immunization, the enhancing effect of DEP on anti-OA IgE antibody production was demonstrated when mice were immunized with intranasal inoculation of OA and DEP. The possibility cannot be excluded that DEP, which are kept buoyant in the environmental atmosphere of urban districts, may exert an adjuvant activity for IgE antibody production after being inhaled into the human body and have some relation to the mechanism of the outbreak of allergic rhinitis caused by pollens in Japan.

Degranulation from human eosinophils stimulated with C3a and C5a.

It is unclear what actually induces eosinophil degranulation in vivo. We examined eosinophil cationic protein (ECP) release from normal human eosinophils (Eos) in response to C3a and C5a. C3a and C5a induced remarkable ECP release when Eos were preincubated with cytochalasin B. ECP release induced by C3a or C5a was greater than that induced by PAF at a concentration of 10(-7) M. The ED50 for ECP release was 3 x 10(-8) M and 3 x 10(-9) M for C3a and C5a, respectively. C3a or C5a elicited a rapid and transient rise in [Ca2+]i. These results suggest that C3a and C5a may contribute to hypersensitivity diseases by inducing eosinophil degranulation.

Enhancing Effect of Suspended Particulate Matter on the IgE Antibody Production in Mice

Suspended particulate matter (SPM), suspended in the polluted environmental atmosphere, are perpetually inhaled into the human body and are considered to have profound effects on human health. This study investigated the enhancing effect of SPM on the IgE antibody production in mice. The IgE antibody responses in mice immunized with intranasal administration of ovalbumin (OA) plus SPM at 3-week intervals were higher than responses in the animals immunized with OA alone. When the dose of OA administered as an antigen was 0.25 microgram, the time course and magnitude of enhancement by SPM was comparable to those by killed Bordetella pertussis, a common adjuvant. SPM had an enhancing effect on IgE antibody production even in a small dose such as 0.25 microgram administered at 3-week intervals. The possibility cannot be excluded that the natural exposure of humans to SPM in the environmental atmosphere may explain the high prevalence rate of allergic rhinitis caused by pollens in polluted districts in Japan.

Topical thrombin-induced IgE-mediated anaphylaxis: RAST analysis and skin test studies☆

Bovine topical thrombin (BTT) is a heterologous plasma thrombin concentrate that has been frequently used for the hemostasis since the 1940s. Recently, three patients in Japan went into shock after the topical application of BTT at lesion sites, and two of these patients had received BTT repeatedly. The clinical symptoms and the increased anti-BTT percent RAST counts suggest that these reactions were shock mediated by anti-BTT IgE antibodies. The RAST-inhibition analysis suggested that the antigenic substance(s) were bovine-specific moiety(ies) mainly involved in the contaminant rather than bovine thrombin itself. The skin tests were studied to predict such allergic reactions. The intracutaneous test provoked nonspecific reactions even at the low concentrations of BTT. The prospective study on the predictive value of the prick test with 1000 U/ml (1 mg/ml) of BTT in 192 patients suggested that it is useful to detect highly sensitive patients. In addition, the increased levels of anti-BTT IgE antibodies in patients 1 month after the single administration of BTT suggested the immunogenicity of the topical application of BTT.

Release of granule proteins from human eosinophils stimulated with mast‐cell mediators

Background It has been suggested that mast cells and eosinophils are major effector cells in the pathogenesis of allergic diseases. However, the interaction of these cells has not been thoroughly elucidated. We examined eosinophil cationic protein (ECP) release and cytosolic free calcium concentration ([Ca2+]) in human eosinophils induced by the major mast‐cell mediators including cytokines.

Effects of interleukin (IL)‐3 and IL‐5 on human eosinophil degranulation induced by complement components C3a and C5a

It is suggested that eosinophils (Eos) play an important role in the pathogenesis of bronchial asthma by releasing cytotoxic cationic eosinophil granule proteins and damaging bronchial epithelial cells. However, the exact nature of the actual inducer of eosinophil degranulation in vivo is unclear. We examined eosinophil cationic protein (ECP) release from human Eos in response to soluble agonists such as C5a, C3a, platelet‐activating factor, and FMLP with or without interleukin (IL)‐3 or IL‐5 priming. Eosinophil degranulation induced by these soluble agonists required the pretreatment of Eos by cytochalasin B even in IL‐3 priming. Among four agonists, C5a was the most effective stimulus of ECP release either with or without IL‐5 priming. IL‐3 and IL‐5 remarkably enhanced ECP release in Eos triggered by C3a and C5a. The enhancement of ECP release by IL‐3 and IL‐5 occurred at 0.1–0.3 ng/ml and became maximal at 10–30 ng/ml, concentration‐dependently. The enhancement of ECP release by cytokines became optimal at an interval of 10 min. Our data support the importance of complement components and cytokines in eosinophil degranulation in vivo.

Regulation of Mediator Release by Human Basophils: Importance of the Sequence and Time of Addition in the Combined Action of Different Agonists

Biologically active molecules affecting basophil function can be divided into 4 groups according to their capacity to induce basophil degranulation and/or leukotriene generation: (1) full agonists such as anti-IgE or fMLP, which induce both histamine and leukotriene release; (2) partial agonists such as C5a, which induces degranulation only; (3) incomplete agonists such as neutrophil-activating peptide-1, platelet-activating factor or C3a, which induce mediator release only after cytokine preincubation, and (4) basophil response modifiers, such as interleukin-3, interleukin-5 and granulocyte/macrophage- colony-stimulating factor, which (a) enhance the releasability to all basophil agonists, (b) change the mediator profile, (c) enhance the rate of mediator release, (d) render basophils responsive to lower agonist concentrations and (e) render basophils responsive to incomplete agonists. We demonstrated that histamine release and de novo synthesis of lipid mediators are clearly separately regulated, and that combined actions of different molecules are of importance. In particular, the type(s), the time interval and the sequence of action of basophil-activating molecules are crucial for the final outcome of the basophil release reaction.

Cefotiam-induced IgE-mediated occupational contact anaphylaxis of nurses ; case reports, RAST analysis, and a review of the literature.

Cefotiam (CTM) is one of the most popular cephem antibiotics in Japan. Recently we experienced two cases of nurses with CTM‐induced contact anaphylaxis. When they were preparing drip infusions of antibiotics or working around other nurses doing so, they suddenly fell into shock with other symptoms such as flushing, urtiearia, abdominal distress, vomiting, dyspnoea and or loss of consciousness. The symptoms never occurred after they avoided exposure to CTM. Passive cutaneous or open patch tests were positive for CTM. Histamine release was induced by CTM from washed leucocytes. RAST analysis using CTM‐human serum albumin‐coupled dises showed high % RAST count, suggesting that these reactions were mediated by IgE antibodies. A RAST inhibition test suggested that the methyl‐thiotetrazol side‐chain was the main antigenic determinant. Both patients had hand dermatitis that had appeared preceding the episodes of anaphylaxis. Although the dermatitis had been resistant to treatments, it also disappeared after they avoided exposure to CTM, It seemed likely that it was also induced or exacerbated by CTM and facilitated the penetration of CTM to cause anaphylaxis. The literature is also reviewed.

Eosinophil Adhesion to Human Bronchial Epithelial Cells: Regulation by Cytokines

BACKGROUND Eosinophil infiltration into the airways and interaction with bronchial epithelial cells are important in the pathogenesis of asthma. The purpose of the present study was to elucidate the regulatory mechanisms of eosinophil adhesion to human bronchial epithelial cells. METHODS We cultured a human bronchial epithelial cell line, BEAS-2B, on a collagen-coated glass slide. Highly purified human eosinophils were added to each well to allow attachment to epithelium for 30 min. The number of attached eosinophils was counted. RESULTS Eosinophil adhesion to epithelial cells was increased when the BEAS-2B cells were pretreated with interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Although IFN-gamma upregulated ICAM-1 expression as shown by flow cytometry, specific neutralizing antibody to ICAM-1 failed to block eosinophil adhesion. Dexamethasone significantly suppressed eosinophil adhesion to bronchial epithelial cells. CONCLUSION Eosinophil adhesion to bronchial epithelium was dynamically regulated by cytokines, and this process might be a target for therapeutic intervention in the treatment of asthma.