Abstract
Despite frequent spillover of sarbecoviruses, most SARS-related viruses discovered in animals fail to engage human ACE2 (hACE2), limiting mechanistic insight and risk assessment. Here we developed antibody-based chimeric entry receptors (ABCERs) that reprogram antibody-antigen recognition into a synthetic, cell-anchored receptor interface. By replacing the extracellular protease domain of hACE2 with single-chain variable fragments (scFvs) from broadly neutralizing antibodies, ABCERs mimic viral receptor engagement while preserving the intracellular architecture required for cathepsin L-dependent endocytic fusion. This modular design converts antibody specificity into a programmable entry module, supporting efficient infection and replication of diverse sarbecoviruses from both clinical and animal sources. Among the tested scFvs, E7 exhibited exceptional breadth, recognizing conserved epitopes shared across representative sarbecoviruses from all clades. Sera from Pfizer-BioNTech mRNA-vaccinated individuals potently blocked E7 binding to SARS-CoV-2 but showed limited cross-inhibition of E7 interactions with RBDs from hACE2-independent sarbecoviruses, revealing a substantial gap in current vaccine-induced humoral immunity. Together, our findings establish E7-based ABCERs as a programmable synthetic receptor platform that bridges antibody recognition and viral propagation, offering a universal tool for isolating, studying, and surveying sarbecoviruses beyond the hACE2-dependent paradigm.