Comprehensive profiling of antibody responses to the human anellome using programmable phage display
Viruses belonging to the diverse Anelloviridae family represent a major constituent of the commensal human virome. Aside from their widespread prevalence and persistence in humans and their absence of detectable pathologic associations, little is known about the immunobiology of the human anellome. In this study, we employed the Phage ImmunoPrecipitation Sequencing (PhlP-Seq) assay for comprehensive analyses of antibody binding to 56 amino acid long anellovirus peptides. We designed and constructed a large and diverse "AnelloScan" T7 phage library comprising more than 32,000 non-redundant peptides representing the ORF1, ORF2, ORF3 and TTV-derived apoptosis-inducing protein (TAIP) sequences of more than 800 human anelloviruses (spanning three genera). We used this library to profile the antibody reactivities of serum samples from 156 subjects. The vast majority of anellovirus peptides were not reactive in any of the subjects tested (n=~28,000; ~85% of the library). Antibody reactive peptides were largely restricted to the C-terminal region of the putative capsid protein, ORF1. To characterize antibody responses to newly acquired anellovirus infections, we screened a longitudinal cohort of matched blood-transfusion donors and recipients. Most transmitted anelloviruses did not elicit detectable antibody reactivity in the recipient (29 out of a total of 40 transmitted anelloviruses) and the remainder demonstrated delayed reactivity (~100-150 days after transfusion). This study represents the first large-scale epitope-level serological survey of the antibody response to the human anellome. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/486145v1_ufig1.gif" ALT="Figure 1"> View larger version (41K): org.highwire.dtl.DTLVardef@132dfforg.highwire.dtl.DTLVardef@130c47dorg.highwire.dtl.DTLVardef@b3fc97org.highwire.dtl.DTLVardef@8c49f9_HPS_FORMAT_FIGEXP M_FIG C_FIG