Page 285 - Veterinary Immunology, 10th Edition
P. 285
development of inappropriate immune responses to commensals
VetBooks.ir and food.
cDC1 and cDC2 Cells
When cDCs stimulate helper T cells, they generate three signals.
The first signal is delivered when T cell antigen receptors bind
antigen fragments attached to MHC molecules. The second signal
provides the cells with additional critical costimulation through cell
surface molecules such as CD40 and CD80/86. The third signal
determines the direction in which naïve helper T cells will develop
and is provided by secreted cytokines. For example, some microbial
antigens trigger cDCs to secrete IL-12 (Fig. 10.7). These are called
cDC1 cells since their IL-12 activates Th1 cells and triggers type 1
responses. Other microbial antigens induce cDCs to secrete IL-1 and
IL-6. These cytokines stimulate Th2 differentiation and are
produced by cDC2 cells. They stimulate type 2 responses. Other
antigens may induce cDC2s to secrete IL-23 and so provoke the
development of Th17 cells.
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