Seroprevalence of human polyomavirus 9 and cross-reactivity to African green monkey-derived lymphotropic polyomavirus

Abstract

Human polyomavirus 9 (HPyV9) was discovered recently in immunocompromised patients and shown to be genetically closely related to B-lymphotropic polyomavirus (LPyV). No serological data are available for HPyV9, but human antibodies against LPyV have been reported previously. To investigate the seroepidemiology of HPyV9 and the sero-cross-reactivity between HPyV9 and LPyV, a capsomer-based IgG ELISA was established using the major capsid protein VP1 of HPyV9 and LPyV. VP1 of an avian polyomavirus was used as control. For HPyV9, a seroprevalence of 47 % was determined in healthy adults and adolescents (n5328) and 20 % in a group of children (n5101). In both groups, the seroreactivities for LPyV were less frequent and the ELISA titres of LPyV were lower. Of the HPyV9-reactive sera, 47 % reacted also with LPyV, and the titres for both PyVs correlated. Sera from African green monkeys, the natural hosts of LPyV, reacted also with both HPyV9 and LPyV, but here the HPyV9 titres were lower. This potential sero-cross-reactivity between HPyV9 and LPyV was confirmed by competition assays, and it was hypothesized that the reactivity of human sera against LPyV may generally be due to cross-reactivity between HPyV9 and LPyV. The HPyV9 seroprevalence of liver transplant recipients and patients with neurological dysfunctions did not differ from that of age-matched controls, but a significantly higher seroprevalence was determined in renal and haematopoietic stem-cell transplant recipients, indicating that certain immunocompromised patient groups may be at a higher risk for primary infection with or for reactivation of HPyV9. INTRODUCTIONHuman polyomavirus 9 (HPyV9) is the most recently identified of the nine human polyomaviruses (PyVs) reported to date, and was first detected in a renal transplant patient (Scuda et al., 2011). Later, the same virus was also found in human skin (Sauvage et al., 2011).PyVs are small, non-enveloped, circular dsDNA viruses. Primary infection with BK virus (BKV) and JC virus (JCV) occurs in childhood and is usually asymptomatic (Moens & Johannessen, 2008). Subsequently, these viruses establish a latent infection. Reactivation can occur in immunocompromised patients and cause serious disease, such as BKVassociated nephropathy or haemorrhagic cystitis (Gardner et al., 1971;Jiang et al., 2009), JCV-associated progressive multifocal leukoencephalopathy (Hou & Major, 2000;Jiang et al., 2009;Padgett et al., 1971) and trichodysplasia spinulosa caused by trichodysplasia spinulosa-associated PyV (Matthews et al., 2011;van der Meijden et al., 2010). PyVs have been shown to transform cells in vitro and to be tumorigenic in small laboratory rodents (Chen et al., 1989;Eddy et al., 1962;Gross, 1953;Stewart, 1953). BKV and JCV have been implicated aetiologically in a number of human cancers, but this issue is still controversial Maginnis & Atwood, 2009;zur Hausen, 2008). Merkel cell PyV (MCPyV) plays a causative role in Merkel cell carcinoma, a rare but aggressive skin cancer Feng et al., 2008).PyV serology has bee...

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

“…(Fig. 3a), synthesized, expressed in Escherichia coli K12 and purified as described previously [58]. Sera of n=54 patients with malignant diseases (MD) of the GIT, n=32 patients with non-malignant diseases (NMD) of the GIT, and a sex-and age-matched control group of n=100 healthy blood donors (BD) were tested with ELISA for reactivity against the purified TAg sequences as described in the Methods.…”

“…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).…”

“…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). The expression and purification of His-tagged proteins, and ELISA protocol were essentially as described previously for PyV VP1 proteins [58]. The cut-off value (COV) for the ELISA was determined experimentally.…”

“…The background reactivities detected in wells without antigen coating and those without both antigen and serum (blanks) were subtracted from the ODs measured in VP1-coated wells. The COV defining a positive serological response was defined as the mean of all negative OD values plus standard deviation [58]. 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.…”

“…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].…”