Page 241 - Veterinary Immunology, 10th Edition

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FIG. 8.11 Signal transduction mediated through T cell antigen
receptors generates three transcription factors: NF-AT, NF-κB, and
AP-1. When TCRs cluster, they activate several protein kinases.
The most important of these is called ZAP-70. This in turn triggers
three signaling pathways, and with appropriate costimulation,
generates multiple transduction factors. The jun-fos heterodimer
(AP-1) is required to stimulate the genes for cytokines and their
receptors. The final results of the stimulus include cell division or
apoptosis as well as cytokine production.

In B cell antigen receptors, the adaptor molecules Ig-α and Ig-β
also have ITAMs. When aggregated by antigen and costimulated by
CD19, they activate the src kinases, lyn and fyn. These in turn
activate phospholipase C and eventually generate both NF-κB and

NF-AT (Fig. 8.12).

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