Identification of a Novel Human Polyomavirus in Organs of the Gastrointestinal Tract

Abstract

Polyomaviruses are small, non-enveloped viruses with a circular double-stranded DNA genome. Using a generic polyomavirus PCR targeting the VP1 major structural protein gene, a novel polyomavirus was initially identified in resected human liver tissue and provisionally named Human Polyomavirus 12 (HPyV12). Its 5033 bp genome is predicted to encode large and small T antigens and the 3 structural proteins VP1, VP2 and VP3. Phylogenetic analyses did not reveal a close relationship to any known human or animal polyomavirus. Investigation of organs, body fluids and excretions of diseased individuals and healthy subjects with both HPyV12-specific nested PCR and quantitative real-time PCR revealed additional virus-positive samples of resected liver, cecum and rectum tissues and a positive fecal sample. A capsomer-based IgG ELISA was established using the major capsid protein VP1 of HPyV12. Seroprevalences of 23% and 17%, respectively, were determined in sera from healthy adults and adolescents and a pediatric group of children. These data indicate that the virus naturally infects humans and that primary infection may already occur in childhood.

Large T antigen variants of human polyomaviruses 9 and 12 and seroreactivity against their N terminus

“…Genomes of HPyV9 (HQ696595; [48]) and HPyV12 (JX308829; [49]) were commercially synthesized and delivered inserted into a plasmid (MrGene and Biomatik, respectively). For transfection, the genomes were excised from the plasmid and re-ligated.…”

“…qPCR (TaqMan), with primers and probe specific for HPyV9 and HPyV12 VP1, respectively, was performed essentially as described before [49,58]. Expression of recombinant TAg proteins, ELISA and statistical analysis Nucleic acid sequences that encode the N-terminal 78 aa of HPyV9, HPyV12, BKPyV, MCPyV and BFDPyV LTAgs were codon-optimized and commercially synthesized (GeneArt; Life Technologies).…”

“…To ensure that the final A 450 values measured for HPyV9, HPyV12, BKPyV and MCPyV TAgs were not derived in part from antibodies to epitopes conserved among the PyVs or resulting from antibodies non-specific for PyVs, the reactivity of the sera to the LTAg N terminus of the avian PyV BFDPyV was measured (mean A 450 =0.07), and the values obtained for each serum sample were subtracted from the A 450 values measured for HPyV9, HPyV12, MCPyV and BKPyV LTAgs. This was essentially as done before for reactivity of human sera against HPyV12 VP1 [49]. The data were analysed with a t-test to estimate the significance of differences among independent groups of individuals.…”

“…In addition, retained samples from anonymized blood donors collected after the retention period were used in this study. They were taken from a panel that had already been studied previously for polyomavirus seroprevalence [49,58].…”

“…We recently discovered two hitherto unknown human polyomaviruses, human polyomavirus 9 (HPyV9) in the serum of a kidney transplant recipient in 2011 [48], and human polyomavirus 12 (HPyV12) in metastatic liver tissue of patients with colorectal cancer [49]. Both viruses are circulating in the human population, as seroprevalences of 20-70 % against VP1 of HPyV9 have been readily detected in several studies, and for HPyV12 a VP1-based seroprevalence of 23 % was reported.…”