Correction: Molecular modelling of the HCMV IL-10 protein isoforms and analysis of their interaction with the human IL-10 receptor.

[This corrects the article DOI: 10.1371/journal.pone.0277953.].

Molecular modelling of the HCMV IL-10 protein isoforms and analysis of their interaction with the human IL-10 receptor.

The human cytomegalovirus (HCMV) UL111A gene encodes several homologs of the cellular interleukin 10 (cIL-10). Alternative splicing in the UL111A region produces two relatively well-characterized transcripts designated cmvIL-10 (isoform A) and LAcmvIL-10 (isoform B). The cmvIL-10 protein is the best characterized, both structurally and functionally, and has many immunosuppressive activities similar to cIL-10, while LAcmvIL-10 has more restricted biological activities. Alternative splicing also results in five less studied UL111A transcripts encoding additional proteins homologous to cIL-10 (isoforms C to G). These transcripts were identified during productive HCMV infection of MRC-5 cells with the high passage laboratory adapted AD169 strain, and the structure and properties of the corresponding proteins are largely unknown. Moreover, it is unclear whether these protein isoforms are able to bind the cellular IL-10 receptor and induce signalling. In the present study, we investigated the expression spectrum of UL111A transcripts in fully permissive MRC-5 cells and semi permissive U251 cells infected with the low passage HCMV strain TB40E. We identified a new spliced transcript (H) expressed during productive infection. Using computational methods, we carried out molecular modelling studies on the three-dimensional structures of the HCMV IL-10 proteins encoded by the transcripts detected in our work (cmvIL-10 (A), LAcmvIL-10 (B), E, F and H) and on their interaction with the human IL-10 receptor (IL-10R1). The modelling predicts clear differences between the isoform structures. Furthermore, the in silico simulations (molecular dynamics simulation and normal-mode analyses) allowed us to evaluate regions that contain potential receptor binding sites in each isoform. The analyses demonstrate that the complexes between the isoforms and IL-10R1 present different types of molecular interactions and consequently different affinities and stabilities. The knowledge about structure and expression of specific viral IL-10 isoforms has implications for understanding of their properties and role in HCMV immune evasion and pathogenesis.

Human Cytomegalovirus DNA Quantification and Gene Expression in Gliomas of Different Grades.

Gliomas are the most common type of primary brain tumors. The most aggressive type, Glioblastoma multiforme (GBM), is one of the deadliest human diseases, with an average survival at diagnosis of about 1 year. Previous evidence suggests a link between human cytomegalovirus (HCMV) and gliomas. HCMV has been shown to be present in these tumors and several viral proteins can have oncogenic properties in glioma cells. Here we have investigated the presence of HCMV DNA, RNA and proteins in fifty-two gliomas of different grades of malignancy. The UL83 viral region, the early beta 2.7 RNA and viral protein were detected in 73%, 36% and 57% by qPCR, ISH and IHC, respectively. Positivity of the viral targets and viral load was independent of tumor type or grade suggesting no correlation between viral presence and tumor progression. Our results demonstrate high prevalence of the virus in gliomas from Brazilian patients, contributing to a better understanding of the association between HCMV infection and gliomas worldwide and supporting further investigations of the virus oncomodulatory properties.

High prevalence of HCMV and viral load in tumor tissues and peripheral blood of glioblastoma multiforme patients.

Glioblastoma multiforme is the most prevalent and malignant tumor of the central nervous system. In the last few years, accumulating evidence has suggested an association between human cytomegalovirus (HCMV) infection and glioblastoma multiforme. In this study, tumor tissues and peripheral blood of patients with glioblastoma multiforme were examined for the presence of HCMV DNA. Twenty-two fresh surgical brain specimens and 20 peripheral blood samples were analyzed by real-time PCR (qPCR) and hemi-nested PCR (nPCR) for the presence of pp65 and (glycoprotein B) gB viral genomic regions, respectively. HCMV DNA was detected in the majority of the tumor samples analyzed (95% by qPCR and 91% by nPCR). About half of the patients with tumors positive for HCMV also had detectable viral DNA in their peripheral blood (47% by qPCR and 61% by nPCR). Genome copy numbers were determined and in the majority of the tumor samples cellular DNA outnumbers viral DNA (average of 1 infected cell in 33 cells). The gB genotypes were determined in HCMV-positive samples and gB2 was the most prevalent genotype in the tumor and blood samples. The results show a high prevalence of HCMV in glioblastoma multiforme samples reinforcing a possible association between HCMV infection and tumor development.