Regulation of CD4+ T cell differentiation

Naive T cells can be induced to differentiate from an uncommitted precursor to T helper 1 (Th1) and Th2 cells. During this differentiation, genes for transcription factors are activated, and transcription factors such as AP-1 accumulate. To study this activation, we have developed reporter transgenic mice for a number of factors, including AP-1. Naive T cells require two signals to activate AP-1. However, upon becoming effector cells, activation through diacylglycerol analogues is sufficient. Rested effector cells lose accumulated AP-1, and the induction of AP-1 synthesis requires both Ca2+ diacylglycerol signals, but not co-stimulation.