Researchers Describe Antibody-Directed Xenophagy, a Cell-Intrinsic Pathway That Destroys Invaders

Overview

• The authors published a Molecular Cell paper June 4, 2026, naming the pathway antibody-directed xenophagy (ADX) and presenting genetic, imaging and mouse-model evidence for its existence.
• ADX begins when the intracellular E3 ligase TRIM21 binds antibodies already attached to a virus or bacterium and marks the complex with ubiquitin to signal danger to the cell.
• High-resolution and live-cell microscopy show ubiquitin triggers assembly of LC3-positive autophagosome membranes around the antibody–TRIM21–pathogen complex, which are then delivered to acidic lysosomes for degradation.
• The study demonstrates ADX acts against diverse pathogens, including adenovirus in human cell lines and intracellular Salmonella in mice, and loss of TRIM21 reduces a component of antiviral protection in vivo.
• Authors propose long-term therapeutic ideas—using antibodies or small molecules to flag pathogens or boosting TRIM21 activity—but stress those concepts are speculative and require substantial further research.