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

Anelloviruses represent a major constituent of the commensal human virome; however, little is known about their immunobiology. Here, we present "AnelloScan," a T7 phage library representing the open reading frame 1 (ORF1), ORF2, ORF3, and torque teno virus (TTV)-derived apoptosis-inducing protein (TAIP) sequences of more than 800 human anelloviruses and profile the antibody reactivities of serum samples from a cross-sectional cohort of 156 subjects by using phage-immunoprecipitation sequencing (PhIP-Seq). A majority of anellovirus peptides are not reactive in any of the subjects tested (n = ∼28,000; ∼85% of the library). Antibody-reactive peptides are largely restricted to the C-terminal region of the capsid protein ORF1. Moreover, using a longitudinal cohort of matched blood-transfusion donors and recipients, we find that most transmitted anelloviruses do not elicit a detectable antibody reactivity in the recipient and that the remainder elicit delayed responses appearing ∼100-150 days after transfusion.

Global genome analysis reveals a vast and dynamic anellovirus landscape within the human virome.

Anelloviruses are a ubiquitous component of healthy human viromes and remain highly prevalent after being acquired early in life. The full extent of "anellome" diversity and its evolutionary dynamics remain unexplored. We employed in-depth sequencing of blood-transfusion donor(s)-recipient pairs coupled with public genomic resources for a large-scale assembly of anellovirus genomes and used the data to characterize global and personal anellovirus diversity through time. The breadth of the anellome is much greater than previously appreciated, and individuals harbor unique anellomes and transmit lineages that can persist for several months within a diverse milieu of endemic host lineages. Anellovirus sequence diversity is shaped by extensive recombination at all levels of divergence, hindering traditional phylogenetic analyses. Our findings illuminate the transmission dynamics and vast diversity of anelloviruses and set the foundation for future studies to characterize their biology.