Integrin activation by various means. Red represents α-subunit; and blue, β-subunit. Activating agents are shown in green. (A) αLβ2-Integrin activation recreated by antibodies. CBR LFA-1/2 locks β2-integrin in extended conformation. MEM148 stabilizes the head piece in an open active conformation, whereas 7E4 locks it in a closed inactive conformation. Using a different combination of antibodies, Chen et al stabilized integrins in inactive, intermediate, or active state.⁴⁰  For a complete description of antibodies, the reader is referred to Byron et al.⁸⁵  (B) Integrin activation induced by synthetic peptides that bind to integrin TMD, by mutations, or by a glycan wedge.