Figure 3.

Proposed periodic arrangement of CTLA-4 molecules on the surface of a T cell bound to B7-1 molecules on the surface of an antigen-presenting cell. This model is based on the molecular association of CTLA-4 and B7.1 observed in the crystal lattice structure. The proposed lattice structure would enhance the stability of CTLA-4 and B7.1 interactions on the cell surface. C, carboxyl terminus; N, amino terminus. Reproduced with permission from [15].