Comprehensive profiling of antibody responses to the human anellome using programmable phage display

Anelloviruses are the most prevalent commensal-viral DNA family in humans, present in essentially every adult, yet their immunobiology has been serologically opaque because no virus-by-virus assay can scale across more than 800 known genotypes. AnelloScan — a programmable T7 phage-display library tiling the open reading frames of these viruses — turns the entire anellome into a single PhIP-Seq readout.

Out of roughly 28,000 distinct anellovirus peptides displayed, the great majority — around 85% — failed to bind antibodies from any subject in the 156-person cohort. To probe how the responses that do exist arise in real time, the authors then turned to a longitudinal cohort of matched blood-transfusion donors and recipients: most anelloviruses transmitted by transfusion produced no detectable antibody response in the recipient at all, and the responses that did appear emerged only after a delay of roughly 100–150 days post-transfusion.

Together, these data argue that the human immune system tolerates the great bulk of the anellome, with reactivity narrowly directed at a small subset of capsid epitopes — a profile that helps explain how anelloviruses persist as a chronic commensal infection in essentially all humans. Anellovirus titer is already in clinical use as a real-time biomarker of net immunosuppression in solid-organ and stem-cell transplant recipients; an antibody-resolved view of which epitopes the immune system actually tracks gives transplant groups a richer instrument than total-load qPCR alone.