The Feeding of .BETA.-Carotene Down-Regulates Serum IgE Levels and Inhibits the Type I Allergic Response in Mice

Abstract

The incidence of type I allergic disorders is increasing; particularly, hypersensitivity to food and airborne allergens.1-3) The mechanism of Type I allergy includes a series of events, 4,5) namely, production of antigen-specific IgE, binding of IgE to the FceRI receptor on mast cells or basophiles, cross-linking of IgE with newly absorbed allergens, and release of chemical mediators such as histamine and leukotrienes from cells. Inhibition of any of the steps in this sequence leads to the attenuation of allergic symptoms. Several drugs, such as corticosteroids, epinephrine, histamine antagonists, and leukotriene synthesis inhibitors, interfere with the above reactions. 6) However, the effect of these drugs is short-lived, and thus, a more fundamental means of preventing allergies would be desirable.It has been reported in numerous observational epidemiological studies that the intake of vegetables, including carrots, is associated with the prevention of several degenerative diseases.7-13) These reports suggest that vegetables have the potential to modulate or regulate the host immune response, resulting in an overall beneficial effect on the immune response. We have already shown evidence that the feeding of carrots (Daucas carota L. var. sativa DC.) to BALB/c mice sensitized with ovalbumin (OVA) inhibited IgE and IgG1 production.14) However, it is still unclear what kind of components in carrots could exhibit this activity.b-Carotene is one of the major nutritional components and is present at high levels especially in carrots. On the other hand, much attention has also been paid to the role of bcarotene intake in the prevention of cancer and life style-related diseases, such as cardiovascular disease. [15][16][17] In the present study, we examined the feeding of bcarotene on the production of specific IgE antibody, specific IgG1 antibody and specific IgG2a antibody. We also examined the effect of feeding b-carotene on antigen-induced active systemic anaphylactic shock (ASA), such as the decrease in body temperature and the rise of serum histamine levels. Furthermore, to clarify the active mechanism by b-carotene intake in the inhibition of specific IgE production, we examined the pattern of cytokine production by spleen cells from mice fed carrots. MATERIALS AND METHODS Mice and Drinking ProtocolsFemale BALB/c mice, 3-4 weeks of age, were purchased from Japan SLC (Hamamatsu, Shizuoka, Japan). Mice were maintained in a temperature (23-25°C)-, humidity (40-60%)-and light-controlled environment. Animals were allowed free access to a powdered MF diet (Japan SLC) and water throughout the experiment. The MF diet containing b-carotene was prepared by mixing the MF diet with levels of b-carotene of 20 mg/kg. The control group (nϭ5) and the b-carotene group (nϭ5) had free access to the MF diet and the MF diet containing bcarotene, respectively.As far as dose-dependent study was concerned, spiked levels in the MF diet were 0 mg/kg (nϭ5), 2 mg/kg (nϭ5), 10 mg/kg (nϭ5) and 20 mg/kg (nϭ5). The care and use of the experime...

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Chondroitin Sulfate Intake Inhibits the IgE-mediated Allergic Response by Down-regulating Th2 Responses in Mice

“…Blood was withdrawn and serum obtained. The serum samples were stored at Ϫ20°C prior to analysis (33,34). For the study for the induction of active systemic anaphylactic shock, the experimental procedure after the second immunization is described below.…”

“…Antibody (Antigen-specific IgE and IgG1 Isotypes) Titer Determination-The mouse serum titers (reciprocal of serum dilution with fluorescence intensity at 50% of the maximum level) of anti-OVA IgE, IgG1, and IgG2a were determined in triplicate in a 96-well microtiter plate by the method of Teshima et al with some modifications (34,36). Fifty microliters of OVA (Cosmobio Co., 20 g/ml) in 50 mM sodium carbonate buffer, pH 9.5, was added to each well of a 96-well microtiter plate and incubated overnight at 4°C.…”

“…FCM Analysis of Splenocytes-The collected splenocytes from mice were washed twice in PBS containing 2% FBS, and then cell staining analysis was carried out in the following way (28,34). Briefly, 100 l of splenocytes at 2.0 ϫ 10 6 cells/ml in PBS containing 2% FBS and 0.1% NaN 3 was mixed with 1 l of anti-CD16/CD32 monoclonal antibody (BD Pharmingen, San Diego, CA) in a tube and reacted for 5 min at 4°C.…”