Researchers at the MRC Laboratory of Molecular Biology identified a previously undescribed intracellular antimicrobial route called antibody-directed xenophagy (ADX). The work, co-led by Leo James and Tyler Rhinesmith, reported that cells can digest antibody-tagged viruses and bacteria after they cross into the cytosol. The pathway is regulated by TRIM21, a cytosolic protein already known for recognizing antibody-coated viruses and triggering degradation. The study, published in Molecular Cell, connects ADX to TRIM21-driven selective autophagy and demonstrates physiological importance across cellular and animal experiments. From a translational perspective, the discovery reframes infection defense as not only an extracellular immune function but also a targeted intracellular degradation mechanism—potentially enabling antibody or small-molecule therapeutics designed to “mark and clear” intracellular pathogens.