Fig. 1: Design of Fc domain engineered IgG antibody pairs acting as Boolean logic AND gates.
From: Logic-gated antibody pairs that selectively act on cells co-expressing two antigens
a, Schematic of antibody combinations that contain Fc domain modifications designed to induce hetero-hexamer formation only after cell surface target binding, aiming to recruit complement component C1q and induce effector function activation. b, Mutually dependent antibody pairs may act as Bio-Logic AND gates by integrating two antibody-binding input signals into a functional output exclusively on cells or surfaces that co-express both antibody targets. c, Summary of coupled biochemical equilibria illustrating how IgG1-hexamer-C1q avidity can be tuned using K439E/S440K and G236R/G237A mutations to favor hetero-hexamerization over homo-hexamerization. d, Left, an overview of an IgG1 antibody hetero-hexamer based on the IgG1-b12 crystal structure (1HZH)42. Right, detailed view of an Fc hinge domain indicating amino acid positions involved in C1q- (blue) and FcγR binding (purple). The largely shared C1q- and FcγR binding interface (magenta) highlights preferred amino acid positions that differentially modulate C1q and FcγR binding (yellow).
