Chitin Particles are Multifaceted Immune Adjuvants.

Summary of "Chitin Particles are Multifaceted Immune Adjuvants."

RATIONALE:
Chitin is a ubiquitous polysaccharide in fungi, insects, allergens and parasites that is released at sites of infection. Its role in the generation of tissue inflammation, however, is not fully understood.
OBJECTIVES:
We hypothesized that chitin is an important adjuvant for adaptive immunity.
METHODS:
Mice were injected with a solution of ovalbumin and chitin.
MEASUREMENTS:
We used in vivo and ex vivo/in vitro approaches to characterize the ability of chitin fragments to foster adaptive immune responses against ovalbumin and compared these responses to those induced by aluminum hydroxide (alum).
RESULTS:
In vivo, ovalbumin challenge caused an eosinophil-rich pulmonary inflammatory response, Th2 cytokine elaboration, IgE induction and mucus metaplasia in mice that had been sensitized with ovalbumin plus chitin or ovalbumin plus alum. Toll-like receptor-2, MyD88 and IL-17A played critical roles in the chitin-induced and MyD88 and IL-17A played critical roles in the alum-induced responses. In vitro, CD4+ T cells from mice sensitized with ovalbumin plus chitin were incubated with ovalbumin-stimulated bone marrow-derived dendritic cells. In these experiments, CD4+ T cell proliferation, IL-5, IL-13, IFN-gamma and IL-17A production were appreciated. Toll-like receptor-2, MyD88 and IL-17A played critical roles in these in vitro adjuvant properties of chitin. TLR-2 was required for cell proliferation while IL-17 and TLR-2 were required for cytokine elaboration. IL-17A also inhibited the generation of adaptive Th1 responses.
CONCLUSIONS:
These studies demonstrate that chitin is a potent multi-faceted adjuvant that induces adaptive Th2, Th1 and Th17 immune responses. They also demonstrate that the adjuvant properties of chitin are mediated by a pathway(s) that involves and is regulated by TLR-2, MyD88 and IL-17A.

Affiliation

Section of Pulmonary and Critical Care Medicine, Yale University School of Medicine, New Haven, Connecticut, United States.

Journal Details

This article was published in the following journal.

Name: American journal of respiratory and critical care medicine
ISSN: 1535-4970
Pages:

Links

• PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20656945
• DOI: http://dx.doi.org/10.1164/rccm.200912-1877OC