Suppression of Th2 immune responses by mekabu fucoidan from Undaria pinnatifida sporophylls.
BACKGROUND
We demonstrated that mekabu fucoidan obtained from Undaria pinnatifida (Up) sporophylls augments the type 1 T-helper (Th1) cell response in normal BALB/c mice. In this study, we examined the effects of the fucoidan of mekabu on the type 2 T-helper (Th2) response in bronchoalveolar lavage fluid (BALF) after ovalbumin (OVA) aerosol challenge.


METHODS
Mekabu fucoidan (50 mg/kg) was injected intraperitoneally into BALB/c mice for 4 days, and then the mice were sensitized with 50 microg/mouse of OVA plus alum (1 mg/mouse) 1 and 8 days later. The mice were challenged with OVA delivered using a nebulizer 7, 8 and 9 days after the second challenge with OVA plus alum. After 24 h, we assessed T cell responses in BALF by measuring the amount of Th2 cytokines (IL-4, IL-5, IL-13) and gamma-interferon (IFN-gamma) produced by Th1 cells.


RESULTS
The production of Th2 cytokines was suppressed (p < 0.05), and the amount of IFN-gamma was not increased in the mice treated with mekabu fucoidan. Anti-OVA immunoglobulin E (IgE) and IgE levels in serum determined after challenge with aerosolized OVA at the end of the experiment were lower (p < 0.05) in the treated than in the control mice.


CONCLUSIONS
The pulmonary inflammation was relieved by mekabu fucoidan, which also downregulated Th2-dominated responses. These results indicate that mekabu fucoidan modulates Th2 responses and might be useful for treating allergic inflammation.
Maruyama
Hiroko
H
Department of Pathology, School of Allied Health Sciences, Kitasato University, Sagamihara, Japan. maruyama@ahs.kitasato-u.ac.jp
Tamauchi
Hidekazu
H
Hashimoto
Minoru
M
Nakano
Takahisa
T
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000276:immunology*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007274:Injections, Intraperitoneal; D007371:Interferon-gamma / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D023421:Models, Animal; D010047:Ovalbumin / Q000009:adverse effects; D011014:Pneumonia / Q000276:immunology*; D011134:Polysaccharides / Q000008:administration & dosage / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D044648:Undaria / Q000276:immunology*
D000893:Anti-Inflammatory Agents; D016207:Cytokines; D011134:Polysaccharides; D007073:Immunoglobulin E; D007371:Interferon-gamma; D010047:Ovalbumin; C007789:fucoidan