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IgE-Mediated Enhancement of CD4+ T Cell Responses in Mice Requires Antigen Presentation by CD11c+ Cells and Not by B Cells.
- Source :
- PLoS ONE; 2011, Vol. 6 Issue 7, p1-9, 9p
- Publication Year :
- 2011
-
Abstract
- IgE antibodies, administered to mice together with their specific antigen, enhance antibody and CD4<superscript>+</superscript> T cell responses to this antigen. The effect is dependent on the low affinity receptor for IgE, CD23, and the receptor must be expressed on B cells. In vitro, IgE-antigen complexes are endocytosed via CD23 on B cells, which subsequently present the antigen to CD4<superscript>+</superscript> T cells. This mechanism has been suggested to explain also IgE-mediated enhancement of immune responses in vivo. We recently found that CD23<superscript>+</superscript> B cells capture IgE-antigen complexes in peripheral blood and rapidly transport them to B cell follicles in the spleen. This provides an alternative explanation for the requirement for CD23<superscript>+</superscript> B cells. The aim of the present study was to determine whether B-cell mediated antigen presentation of IgE-antigen complexes explains the enhancing effect of IgE on immune responses in vivo. The ability of spleen cells, taken from mice 1-4 h after immunization with IgEantigen, to present antigen to specific CD4<superscript>+</superscript> T cells was analyzed. Antigen presentation was intact when spleens were depleted of CD19<superscript>+</superscript> cells (i.e., primarily B cells) but was severely impaired after depletion of CD11c<superscript>+</superscript> cells (i.e., primarily dendritic cells). In agreement with this, the ability of IgE to enhance proliferation of CD4<superscript>+</superscript> T cells was abolished in CD11c- DTR mice conditionally depleted of CD11c<superscript>+</superscript> cells. Finally, the lack of IgE-mediated enhancemen of CD4<superscript>+</superscript> T cell responses in CD23-/- mice could be rescued by transfer of MHC-II-compatible as well as by MHC-II-incompatible CD23<superscript>+</superscript> B cells. These findings argue against the idea that IgE-mediated enhancement of specific CD4<superscript>+</superscript> T cell responses in vivo is caused by increased antigen presentation by B cells. A model where CD23<superscript>+</superscript> B cells act as antigen transporting cells, delivering antigen to CD11c<superscript>+</superscript> cells for presentation to T cells is consistent with available experimental data. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 19326203
- Volume :
- 6
- Issue :
- 7
- Database :
- Complementary Index
- Journal :
- PLoS ONE
- Publication Type :
- Academic Journal
- Accession number :
- 74548342
- Full Text :
- https://doi.org/10.1371/journal.pone.0021760