Oral administration of chitin down-regulates serum IgE levels and lung eosinophilia in the allergic mouse.

Abstract

Previous studies showed that local macrophages phagocytose nonantigenic chitin particles (1-10 micrometer polymers of N-acetyl-<cmd SC>d<cmd /SC> -glucosamine) through mannose receptors and produce IL-12, IL-18, and TNF-alpha. These cytokines lead to the production of IFN-gamma by NK cells. To determine whether chitin could down-regulate Th2 responses, chitin was given orally (8 mg/day for 3 days before and 13 days during ragweed allergen immunization) in BALB/c and C57BL/6 mice. These ragweed-immunized mice were given ragweed intratracheally on day 11. Three days after the challenge, the immunized mice with saline (controls) showed increases in serum IgE levels and lung eosinophil numbers. The chitin treatment resulted in decreases of these events in both strains. To dissect the inhibitory mechanisms of Th2 responses, spleen cells (4 x 106 cells/ml) isolated from the ragweed-immunized mice (controls) were cultured in the presence of ragweed and/or chitin for 3 days (recall responses). Ragweed alone stimulated the production of IL-4 (0.6 ng/ml), IL-5 (20 U/ml), and IL-10 (3.2 ng/ml), but not IFN-gamma. Ragweed/chitin stimulation resulted in significant decreases of IL-4, IL-5, and IL-10 levels and the production of IFN-gamma (48 U/ml). Moreover, spleen cells isolated from the chitin-treated mice showed ragweed-stimulated IFN-gamma production (15 U/ml) and significantly lower levels of the Th2 cytokines, suggesting that the immune responses were redirected toward a Th1 response. Collectively, these results indicate that chitin-induced innate immune responses down-regulate Th2-facilitated IgE production and lung eosinophilia in the allergic mouse.

• Authors: Y Shibata, L A Foster, J F Bradfield, Q N Myrvik
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 164 Issue 3 Pg. 1314-21 (Feb 01 2000) ISSN: 0022-1767 [Print] United States
• PMID: 10640745 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Allergens
• Interleukin-5
• Plant Proteins
• Interleukin-10
• Chitin
• Interleukin-4
• Immunoglobulin E
• Interferon-gamma

Topics

• Administration, Oral
• Allergens (immunology)
• Animals
• Chitin (administration & dosage, therapeutic use)
• Disease Models, Animal
• Down-Regulation (immunology)
• Eosinophilia (immunology, pathology, prevention & control, therapy)
• Female
• Immunoglobulin E (biosynthesis, blood)
• Immunologic Memory
• Interferon-gamma (biosynthesis)
• Interleukin-10 (biosynthesis, metabolism)
• Interleukin-4 (biosynthesis, metabolism)
• Interleukin-5 (biosynthesis, metabolism)
• Lung (immunology, pathology)
• Mice
• Mice, Inbred BALB C
• Mice, Inbred C57BL
• Plant Proteins (immunology)
• Respiratory Hypersensitivity (immunology, pathology, prevention & control, therapy)
• Spleen (cytology, metabolism)