Recognition of Salmonella by Dectin-1 induces presentation of peptide antigen to type B T cells.
Bottom Line: The effect could be mimicked by purified PAMPs, the most potent of which were curdlan and zymosan, β-(1,3)-glucan-containing polymers that are recognized by Dectin-1.Type B T cells have been shown to escape thymic tolerance and to transfer pathology in an autoimmune disease model.The induction of type B responses by gram-negative bacteria provides a mechanism by which autoreactive T cells may be produced during infection.
Affiliation: Division of Immunology, Department of Pathology, University of Cambridge, Cambridge, UK.Show MeSH
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Mentions: To confirm the interaction, we also employed blocking with a Dectin-1-specific Ab reagent (2A11) and laminarin, a soluble β-(1,3)-glucan. As shown in Figure4B, the increase in presentation to type B T cells induced by curdlan was significantly blocked by the anti-Dectin-1 Ab 2A11 (63% inhibition), laminarin (55% inhibition), and anti-Dectin-1 Ab and laminarin in combination (66% inhibition). These reagents also inhibited the response induced by S. Typhimurium where anti-Dectin-1 Ab, laminarin, and combined treatment reduced the presentation to type B T cells by 55, 42, and 61%, respectively (Fig.4A). In all experiments, after stimulation with either curdlan or S. Typhimurium, blocking with anti-Dectin-1 Ab and laminarin alone or in combination resulted in reduced presentation to type B T cells. As the blocking with anti-Dectin-1 Ab alone is similar for stimulation with S. Typhimurium and curdlan (55 and 63%), this suggests that a major component of the stimulation by S. Typhimurium is via Dectin-1. To visualize the results of individual experiments, the combined blocking with 2A11 and laminarin are depicted graphically (Fig.4C). In all cases, blocking resulted in reduced presentation to type B T cells. Together, these studies show that Dectin-1 is expressed on BMDCs and that it can recognize β-(1,3)-glucan present on S. Typhimurium, curdlan, and zymosan. This recognition results in enhanced presentation of peptide Ag to type B T cells.
Affiliation: Division of Immunology, Department of Pathology, University of Cambridge, Cambridge, UK.