Shedding dynamics of Epstein-Barr virus: A type 1 carcinogen

Detection of Felis catus Gammaherpesvirus 1 in Domestic Cat Saliva: Prevalence, Risk Factors, and Attempted Virus Isolation

Felis catus gammaherpesvirus 1 (FcaGHV1) infects domestic cats worldwide, yet it has not been successfully propagated in cell culture, and little is known about how it is shed and transmitted. To investigate the salivary shedding of FcaGHV1, we quantified FcaGHV1 DNA in feline saliva by qPCR. For FcaGHV1-positive saliva, we sequenced a portion of the viral glycoprotein B (gB) gene and attempted to isolate the infectious virus by passage in several felid and non-felid cell lines. We detected FcaGHV1 DNA in 45/227 (19.8%) saliva samples with variable viral DNA loads from less than 100 to greater than 3 million copies/mL (median 4884 copies/mL). Multiple saliva samples collected from an infected cat over a two-month period were consistently positive, indicating that chronic shedding can occur for at least two months. Cat age, sex, and health status were not associated with shedding prevalence or viral DNA load in saliva. Feral status was also not associated with shedding prevalence. However, feral cats had significantly higher FcaGHV1 DNA load than non-feral cats. Sequencing of FcaGHV1 gB showed low sequence diversity and >99.5% nucleotide identity to the worldwide consensus FcaGHV1 gB sequence. We did not detect virus replication during the passage of FcaGHV1-positive saliva in cell culture, as indicated by consistently negative qPCR on cell lysate and supernatant. To our knowledge, these data show for the first time that cats in Canada are infected with FcaGHV1. The data further suggest that shedding of FcaGHV1 in saliva is common, can occur chronically over an extended period of time, and may occur at higher levels in feral compared to non-feral cats.

A phase 2a open-label clinical trial to determine the effect of famciclovir on EBV activity as measured by EBV shedding in the saliva of patients with multiple sclerosis

BACKGROUND

Despite increasing evidence that Epstein-Barr virus (EBV) plays a causal role in MS, no treatments have been shown to reduce EBV turnover. We studied the effect of famciclovir on salivary EBV shedding in people with MS (NCT05283551) in a pilot, proof-of-concept study.

METHODS

People with MS receiving natalizumab provided weekly saliva samples for 12 weeks before starting famciclovir 500 mg twice daily for 12 weeks. Twelve saliva samples were provided on treatment and 12 following treatment. A real-time qPCR Taqman assay was used to detect EBV DNA in saliva. The proportion of saliva samples containing EBV DNA was compared using the Friedman test.

RESULTS

Of 30 participants (19 F; mean age 41 years; median EDSS 3.5), 29 received famciclovir, and 24 completed the 12-week course. Twenty-one participants provided at least one usable saliva sample in all epochs. Ten of the 21 had shedding in at least one sample pre-drug; 7/21 when taking famciclovir (not significant). No difference in EBV DNA copy number was seen. There were no drug-related serious adverse events.

CONCLUSION

No significant effect of famciclovir on EBV shedding was seen in this small pilot study. Given the low numbers, a small effect of famciclovir cannot be excluded. Salivary EBV shedding in this natalizumab-treated cohort was lower than in previous studies, which requires replication.

Viruses, periodontitis, and comorbidities

Seminal studies published in the 1990s and 2000s explored connections between periodontal diseases and systemic conditions, revealing potential contributions of periodontal diseases in the initiation or worsening of systemic conditions. The resulting field of periodontal medicine led to the publication of studies indicating that periodontal diseases can influence the risk of systemic conditions, including adverse pregnancy outcomes, cardiovascular and respiratory diseases, as well as Alzheimer disease and cancers. In general, these studies hypothesized that the periodontal bacterial insult and/or the associated proinflammatory cascade could contribute to the pathogenesis of these systemic diseases. While investigations of the biological basis of the connections between periodontal diseases and systemic conditions generally emphasized the bacteriome, it is also biologically plausible, under an analogous hypothesis, that other types of organisms may have a similar role. Human viruses would be logical "suspects" in this role, given their ubiquity in the oral cavity, association with periodontal diseases, and ability to elicit strong inflammatory response, compromise immune responses, and synergize with bacteria in favor of a more pathogenic microbial consortium. In this review, the current knowledge of the role of viruses in connecting periodontal diseases and systemic conditions is examined. We will also delve into the mechanistic basis for such connections and highlight the importance of those relationships in the management and treatment of patients.

Childcare attendance and risk of infectious mononucleosis: A population-based Danish cohort study

BACKGROUND

The risk of infectious mononucleosis (IM) is affected both by crowding and by sibship structure, i.e., number and signed age differential between an index child and a sibling. Siblings provide protection against IM by pre-empting delayed primary Epstein-Barr virus infection with its associated high risk of IM. The association between childcare attendance and risk of IM, on the other hand, has never been studied in a large, well-characterized cohort.

METHODS

Danish children born in July 1992 through 2016 with a completely known simple childcare attendance history before age 1.5 years (n = 908,866) were followed up for a hospital contact with an IM diagnosis at ages 1.5-26 years. Hazard ratios (HRs) of IM for an additional year of exposure were obtained from stratified Cox regression analyses, stratified by sex and year of birth, with age as the underlying time scale, adjusted for sibship structure, and sociodemographic variables including parental ethnicity and maternal age.

RESULTS

An additional year of exclusively attending a daycare home (max 5 children) yielded HR = 0.90 (95% confidence interval 0.81-1.00), and similarly, each year of exclusively attending a childcare institution (e.g., crèche) yielded HR = 0.94 (0.84-1.06).

CONCLUSIONS

Forwarding enrollment in childcare by a year lowers the risk of IM later in life much less than having an additional sibling of comparable age and has no practical public health implications. We find our results suggestive of a random threshold for successful Epstein-Barr virus infection that is more easily reached by a sibling than the collective of playmates in daycare homes or childcare institutions.

Prevalence of Epstein-Barr virus, human papillomavirus, cytomegalovirus and herpes simplex virus type 1 in patients with diabetes mellitus type 2 in south-eastern Poland

A microbiota is a complex ecosystem of microorganisms consisting of bacteria, viruses, protozoa, and fungi living in different niches of the human body, which plays an essential role in many metabolic functions. Modifications in the microbiota composition can lead to several diseases, including metabolic disorders. The aim of this study was to analyze the prevalence of four viruses which can cause persistent infections-Epstein-Barr virus (EBV), human papillomavirus (HPV), cytomegalovirus (CMV), and herpes simplex virus type 1 (HSV-1) in patients with diabetes mellitus type 2 (DM2). Blood, saliva and oral swabs were collected from all the study participants. The nested-PCR technique was used to detect the viral DNA. DNA of at least one virus was detected in 71.1% of diabetic patients and in 30% of individuals without diabetes. In patients with diabetes EBV DNA was detected the most frequently (25.4%), followed by HPV- 19.1%, HSV- 10.4% and CMV- 5.2%. A higher percentage of EBV+HPV co-infection was found among men (30.8%). EBV DNA was statistically more often detected in patients living in rural areas (53.7%), while HPV (91.5%) and EBV+HPV co-infection (22.2%) prevailed among patients from urban areas. In patients with a DM2 history longer than 10 years viral infection was detected more frequently. The prevalence of EBV, HPV and the EBV+HPV co-infection was significantly higher in diabetic patients than in individuals without diabetes. The frequency of these infections depended on the duration of the disease (DM2).

The T-cell Response to Epstein-Barr Virus-New Tricks From an Old Dog

Epstein-Barr virus (EBV) infects most people and establishes life-long infection controlled by the host's immune system. The genetic stability of the virus, deep understanding of the viral antigens and immune epitopes recognized by the host's T-cell system and the fact that recent infection can be identified by the development of symptomatic infectious mononucleosis makes EBV a powerful system in which to study human immunology. The association between EBV and multiple cancers also means that the lessons learned have strong translational potential. Increasing evidence of a role for resident memory T-cells and non-conventional γδ T-cells in controlling EBV infection suggests new opportunities for research and means the virus will continue to provide exciting new insights into human biology and immunology into the future.

Epstein Barr virus shedding in multiple sclerosis: Similar frequencies of EBV in saliva across separate patient cohorts

BACKGROUND

Epstein Barr Virus (EBV) infection is closely associated with multiple sclerosis (MS), but the relationship between viral load and disease activity is unclear. This study tested the observed levels of salivary EBV in MS, as a first step in investigating this relationship.

METHODS

Real-time quantitative PCR (qPCR) was used to measure EBV DNA levels in saliva samples from three separate Multiple Sclerosis (MS) patient cohorts.

RESULTS

The qPCR assay was used to delineate EBV shedding, defined here as a reliably detectable level of extracellular EBV DNA in saliva. Frequency of EBV shedding was found to be similar across the groups, with 20-25% of subjects releasing virus on any given sampling date. Diurnal variation in EBV count was tested in one of the cohorts, in which 26% of subjects showed more than a 10-fold difference between the highest and lowest EBV levels on a single day. In the same cohort, elevated viral levels at one time point did not predict elevated viral levels at a subsequent time point.

CONCLUSIONS

These results indicate that EBV lytic activity in a subject cannot be inferred from a single measure of EBV in saliva. Also, subjects do not appear to be behave constantly as "EBV shedders" or "non-shedders". The assay is useful in giving a clear indication of salivary gland EBV lytic activity across a patient cohort - for example, in testing anti-viral drugs in MS.

Comparison of two automated instruments for Epstein-Barr virus serology in a large adult hospital and implementation of an Epstein-Barr virus nuclear antigen-based testing algorithm

Serology remains the mainstay for diagnosis of Epstein-Barr virus (EBV) infection. This study compared two automated platforms (BioPlex 2200 and Architect i2000SR) to test three EBV serological markers: viral capsid antigen (VCA) immunoglobulins of class M (IgM), VCA immunoglobulins of class G (IgG) and EBV nuclear antigen-1 (EBNA-1) IgG. Using sera from 65 patients at various stages of EBV disease, BioPlex demonstrated near-perfect agreement for all EBV markers compared to a consensus reference. The agreement for Architect was near-perfect for VCA IgG and EBNA-1 IgG, and substantial for VCA IgM despite five equivocal results. Since the majority of testing in our hospital was from adults with EBNA-1 IgG positive results, post-implementation analysis of an EBNA-based algorithm showed advantages over parallel testing of the three serologic markers. This small verification demonstrated that both automated systems for EBV serology had good performance for all EBV markers, and an EBNA-based testing algorithm is ideal for an adult hospital.

Epstein-Barr virus mRNA profiles and viral DNA methylation status in nasopharyngeal brushings from nasopharyngeal carcinoma patients reflect tumor origin

Undifferentiated nasopharyngeal carcinoma (NPC) is 100% associated with Epstein-Barr virus (EBV) as oncogenic driver. NPC is often diagnosed late due to initial vague complaints and obscured location. Prior studies suggest that measurement of EBV DNA load and RNA transcripts in nasopharyngeal (NP) brushings is useful for minimally invasive NPC diagnosis. However, whether these EBV markers relate to local virus replication or reflect tumor origin remains to be demonstrated. To resolve this, we analysed EBV-DNA characteristics and quantified latent and lytic viral RNA transcripts in NP brushings and matching frozen NP-biopsy specimens from patients suspected of having NPC. We observed non-fragmented and Cp-promotor methylated EBV-DNA in both NP brushings and biopsies suggestive of tumor origin. Using quantitative RT-PCR we determined expression levels of 7 critical latent (EBER1, Qp-EBNA1, EBNA2, BART, LMP1, LMP2, BARF1) and 5 lytic (Zta, Rta, TK, PK and VCA-p18) RNA transcripts. Although latent and early lytic RNA transcripts were frequently detected in conjunction with high EBV viral load, in both brushings and biopsies the latent transcripts prevailed and reflected a typical NPC-associated latency-II transcription profile without EBNA2. Late lytic RNA transcripts were rare and detected at low levels mainly in NP brushings, suggestive of abortive viral reactivation rather than complete virus replication. EBV-IgA serology (EBNA1, VCA, Zta) did not correlate to the level of viral reactivation in situ. Overall, viral RNA profiling, DNA fragmentation and methylation analysis in NP brushings and parallel biopsies indicate that NP brush sampling provides a true and robust indicator of NPC tumor presence.

Shedding of HSV-1, HSV-2, CMV, and EBV in the saliva of hematopoietic stem cell transplant recipients at Fundación HOMI - Hospital de la Misericordia, Bogotá, D.C

INTRODUCTION

Hematopoietic stem cell transplantation in pediatric patients is an alternative treatment for different diseases. The conditioning regimen for transplant predisposes recipients to the development of infections. Viral infections by herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), human cytomegalovirus (CMV), and Epstein-Barr virus (EBV), are the most common, and the leading cause of morbidity and mortality among these patients. These viruses lie dormant in various cell types and the reactivation of latent infections may lead to asymptomatic viral shedding in saliva. The detection of these viruses in secretions may contribute to understand the behavioral dynamics of these viral infections in transplanted patients, and to the early diagnosis of reactivation. 

OBJECTIVE

To assess HSV-1, HSV-2, CMV and EBV viral shedding in the saliva of patients admitted for hematopoietic stem cell transplantation at Fundación HOMI - Hospital de la Misericordia between January and November of 2012. 

MATERIALS AND METHODS

We evaluated stimulated saliva samples of 17 hematopoietic stem cell transplantation recipients weekly. We performed DNA extraction from saliva, and we evaluated the presence of DNA for HSV-1, HSV-2, CMV, and EBV by PCR. 

RESULTS

While we detected HSV-2 and CMV DNA in the saliva of four patients, EBV DNA was detected in nine patients with leukopenia. In contrast, we did not detect HSV-1 DNA in saliva. Additionally, four out of the 17 patients showed a simultaneous shedding of CMV and EBV. 

CONCLUSIONS

By conventional PCR, we demonstrated asymptomatic HSV-2, CMV, and EBV viral shedding in saliva, associated with leukopenia.

Prevalence of Human papillomavirus (HPV) and Epstein-Barr virus (EBV) in oral and oropharyngeal squamous cell carcinoma in south-eastern Poland

OBJECTIVE

The aim of this study was to analyze the prevalence of HPV and EBV in oral and oropharyngeal squamous cell carcinoma in south-eastern Poland. The correlation between viral infection, OSCC, alcohol use, tobacco smoking, demographic data (gender, age, place of residence), anatomic location, pre-treatment staging, evidence of metastases to lymph nodes, and grading was also investigated.

METHODS

The examination samples were collected from paraffin tissue blocks, from 154 patients. Viral DNA was amplified by the nested-PCR method.

RESULTS

HPV DNA was detected in 29.2 % of the tested samples (in 27.4 % of oropharyngeal and in 30.4 % of oral cavity). The HPV type 16 was detected in 15.6 % of all samples, and in 53.3 % of HPV-positive group. In HPV-positive samples from oropharyngeal HPV 16 constitute 76.5 %, and in HPV-positive samples from oral cavity HPV 16 constitute 39.3 %. Mixed infection (more than one type of HPV) was observed in 23.5 and 60.7 %, respectively, and in 46.7 % of all HPV-positive samples, and in 12.3 % of the whole study group. EBV DNA was detected in 27.3 % of the cases and HPV-EBV co-infection in 7.8 % of samples.

CONCLUSIONS

In major patients from Southeastern region of Poland with oropharyngeal cancer HPV type 16 was detected but in oral cavity cancer other mixed infections were observed (i.e. 51, 52, 59, 66, 68, 71, 74). HPV 16 was detected more often among patients younger than 50 years of age, whereas the mixed HPV in the group aged 50-59. The pathogenesis of oral squamous cell carcinoma may be connected with EBV infection. Future studies on the mechanisms of HPV/EBV co-infection and/or superinfection and their role in oral squamous cell carcinoma are necessary.

The herpes simplex virus 1 UL51 gene product has cell type-specific functions in cell-to-cell spread

The herpes simplex virus 1 (HSV-1) UL51 gene encodes a 244-amino-acid (aa) palmitoylated protein that is conserved in all herpesviruses. The alphaherpesvirus UL51 (pUL51) protein has been reported to function in nuclear egress and cytoplasmic envelopment. No complete deletion has been generated because of the overlap of the UL51 coding sequence 5' end with the UL52 promoter sequences, but partial deletions generated in HSV and pseudorabies virus (PrV) suggest an additional function in epithelial cell-to-cell spread. Here we show partial uncoupling of the replication, release, and cell-to-cell spread functions of HSV-1 pUL51 in two ways. Viruses in which aa 73 to 244 were deleted from pUL51 or in which a conserved YXXΦ motif near the N terminus was altered showed cell-specific defects in spread that cannot be accounted for by defects in replication and virus release. Also, a cell line that expresses C-terminally enhanced green fluorescent protein (EGFP)-tagged pUL51 supported normal virus replication and release into the medium but the formation of only small plaques. This cell line also failed to support normal localization of gE to cell junctions. gE and pUL51 partially colocalized in infected cells, and these two proteins could be coimmunoprecipitated from infected cells, suggesting that they can form a complex during infection. The cell-to-cell spread defect associated with the pUL51 mutation was more severe than that associated with gE-null virus, suggesting that pUL51 has gE-independent functions in epithelial cell spread.

IMPORTANCE

Herpesviruses establish and reactivate from lifelong latency in their hosts. When they reactivate, they are able to spread within their hosts despite the presence of a potent immune response that includes neutralizing antibody. This ability is derived in part from a specialized mechanism for virus spread between cells. Cell-to-cell spread is a conserved property of herpesviruses that likely relies on conserved viral genes. An understanding of their function may aid in the design of vaccines and therapeutics. Here we show that one of the conserved viral genes, UL51, has an important role in cell-to-cell spread in addition to its previously demonstrated role in virus assembly. We find that its function depends on the type of cell that is infected, and we show that it interacts with and modulates the function of another viral spread factor, gE.

Epstein-Barr virus: general factors, virus-related diseases and measurement of viral load after transplant

The Epstein-Barr virus is responsible for infectious mononucleosis syndrome and is also closely associated to several types of cancer. The main complication involving Epstein-Barr virus infection, both in recipients of hematopoietic stem cells and solid organs, is post-transplant lymphoproliferative disease. The importance of this disease has increased interest in the development of laboratory tools to improve post-transplant monitoring and to detect the disease before clinical evolution. Viral load analysis for Epstein-Barr virus through real-time polymerase chain reaction is, at present, the best tool to measure viral load. However, there is not a consensus on which sample type is the best for the test and what is its predictive value for therapeutic interventions.

De novo infection of B cells during murine gammaherpesvirus 68 latency

The mechanisms by which gammaherpesviruses maintain latency are unclear. Here we used a murine gammaherpesvirus model to show that previously uninfected B cells in immunocompetent mice can acquire virus during latency. In vivo depletion of T cells allowed viral reactivation, as measured by increased viral loads, but not enhanced transfer of virus to new cells. In the absence of both immune T cells and antibody following the transfer of latently infected cells into naïve animals, there was robust infection of new B cells. These data confirm that both T cells and antibody contribute to the control of gammaherpesvirus latency, reactivation, and spread.