Figure 1.

Co-stimulatory and co-inhibitory pathways in AD. The co-stimulatory and co-inhibitory molecules on APCs and T cells in AD are shown. Red arrows indicate co-stimulation, blue arrows indicate co-inhibition, and red and blue arrows together indicate molecules with co-inhibitory and co-stimulatory functions. Ascending and descending arrows indicate the increase and decrease of co-stimulatory and co-inhibitory molecules in AD, respectively.