Human and mouse Lu-Fc bind laminin 10/11 specifically and with high affinity.

Binding of human laminin 10/11 to recombinant Lu-Fc proteins was examined in an optical biosensor. (A) Human Lu-Fc bound 42-nM purified human laminin 10/11 (10/11) but not 42-nM crude human, placental laminin 2/4 (2/4), or 42-nM mouse, EHS, laminin 1(1). (B) Mouse Lu-Fc bound 42-nM purified human laminin 10/11 (10/11) but not 42-nM crude human, placental laminin 2/4 (2/4), or 42-nM mouse laminin 1(1). (C) Lu-Fc was captured on the anti-Fc surface at time −15 minutes and allowed to associate until the biosensor recorded a response of 100 arc seconds. The Lu-Fc was removed and fresh buffer (PBSt) was added at time −2.5 minutes. Soluble, human laminin 10/11 was applied (final concentration 24 nM) at time 0 minute and association was recorded for 4 minutes before the laminin was exchanged for PBSt and dissociation rate (k_off) of the complex was measured. In all experiments Fc fusion proteins were applied to the anti-Fc matrix to give an instrument response of 100 arc seconds before washing with PBSt, addition of laminin at time 0 minute and measurement of laminin binding. (D) Association rates (k_on) for the interaction of human Lu-Fc with human laminin 10/11 were measured at laminin concentrations in the range 0.1 to 100 nM by curve fitting using the biosensor software; representative data are shown. (E) The measured values for k_on were plotted against laminin concentration and the association rate constant (k_ass) was derived from the gradient of this plot using the biosensor software. (F) Human Lu-Fc but not the structural analogue MUC 18-Fc (MUC18) bound 10 nM laminin 10/11.