FIG. 4.
Potential costimulatory ligand-receptor interactions between NKT cells and APC. A selection of the key costimulatory molecule pairs involved in NKT cell activation is depicted. The CD28 co-stimulatory families are shown above the CD1d:TCR synapse and the CD40 families are shown below. The arrow indicates cross-reaction between the receptor-ligand pair. APC, antigen-presenting cells.