The LFA-1 I-domain: A transient low affinity binding module for ICAM-1
Knorr R., Dustin ML.
Lymphocyte function associated antigen 1 (LFA-1) is a heterodimer, composed of an αL-chain and a β2-chain. The I-domain is inserted in the ctL-chain and contains a binding site for ICAM-1. To study the adhesive interaction between the I-domain and ICAM-I, we constructed a GPIanchored form of the I-domain and expressed it stabily in BHK-cells. In contrast to the whole LFA-1 molecule (Kd=8nM), no interaction between soluble ICAM-1 dimers and I-domain expressing cells could be detected, suggesting that the ICAM-1/I-domain interaction is of low affinity (Kd>33|