Prevalence and in vitro study of human polyomavirus 9

Little is known about human polyomavirus 9 (HPyV9). The mode of transmission and the site of replication are unknown, and seroprevalence data have been published with a wide range. A total of 1038 serum samples from individuals aged 0.7-93 years were used for seroprevalence study. We observed that seropositivity increased with age among children and young adults, and a 36.2% adult seroprevalence was detected. The prevalence was examined in samples from the respiratory tract: cancerous and non-cancerous lung tissues, tonsils, adenoids, throat swabs, middle ear discharge and nasopharyngeal samples collected from children and adults. HPyV9 was detected in 5.2% of nasopharyngeal samples and 1% of tonsils. Upon a viral infection, the interaction of viral promoters and cellular factors may determine whether a virus productively replicates in a cell. The early and late promoter activity of HPyV9 and the effect of the large T antigen (LTAg) on it was investigated in respiratory, kidney, endothelial and colon cell lines, fibroblast and primary airway epithelial cells. The highest promoter activity was measured in A549 lung cell line. LTAg expression significantly increased the late promoter activity. Based on our results, the respiratory cells may be suitable for HPyV9 replication.