Epstein-Barr Virus Coinfection and Recombination in Non-Human Immunodeficiency Virus-Associated Oral Hairy Leukoplakia

Epstein-Barr virus (EBV) strains can be distinguished by specific sequence variations in the LMP1 gene. In this study, a heteroduplex tracking assay (HTA) specific for LMP1 was developed to precisely identify the prototypic undeleted strain B958, other undeleted strains (Ch2, AL, NC, and Med؊), and strains with the 30-bp deletion (Med؉ and Ch1). This technique also provides an estimate of the relative abundance of strains in patient samples. In this study, EBV strains were identified in 25 hairy leukoplakia (HLP) biopsies and six matched peripheral blood samples and throat washes with the LMP1-HTA. To investigate the relationship of the virus found in the peripheral blood to that in the HLP lesion, the strain variants in the peripheral blood B lymphocytes and those present within the epithelial cells in the HLP lesion and in throat washes were identified. In many of the subjects, compartmental differences in the EBV strain profiles in the oral cavity and peripheral blood were readily apparent. The throat wash specimens usually had a strain profile similar to that within the corresponding HLP sample, which was distinct from the strain profile detected in the peripheral blood. These analyses reveal that the nature of EBV infection can be very dynamic, with changes in relative strain abundance over time as well as the appearance of new strains. The patterns of abundance in the blood and oral cavity provide evidence for compartmentalization and for the transmission of strains between the blood and oropharynx.

Section: Resultsmentioning

confidence: 99%

“…HLP is an early indicator of immune suppression and is the only example of pathology caused by permissive EBV infection (15). An unusual characteristic of HLP is the frequent presence of multiple types and strains of EBV (45,46).…”

mentioning

confidence: 99%

Identification of Epstein-Barr Virus Strain Variants in Hairy Leukoplakia and Peripheral Blood by Use of a Heteroduplex Tracking Assay

Sitki-Green

Edwards

Webster‐Cyriaque

et al. 2002

“…Studies examining the major sequence divergence between EBV types 1 and 2 have reported EBV coinfection rates ranging from 0 to 53% (4,13,20,34,35,45). However, EBV types 1 and 2 can both be further subdivided into different strains (1,24,41) and only three studies to date have utilized EBV gene nucleotide sequence variation to define EBV strains in healthy individuals (7,30,38).EBV genotyping assay. A consistent approach is needed for the definition and nomenclature of EBV genomes.…”

mentioning

confidence: 99%

“…Alternatively, they could represent the reactivation of latent EBV strains that were acquired prior to the onset of immunodeficiency. The reported prevalence of multiple EBV infections in healthy individuals ranges broadly between 0 and 100% (Table 1) (4,7,13,16,19,20,23,30,32,35,38,45; M. L. Lung and R. S. Chang, Letter, J. Infect. Dis.…”

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confidence: 99%

Multiple Epstein-Barr Virus Infections in Healthy Individuals

Walling

Brown²,

Etienne³

et al. 2003

100

We employed a newly developed genotyping technique with direct representational detection of LMP-1 gene sequences to study the molecular epidemiology of Epstein-Barr virus (EBV) infection in healthy individuals. Infections with up to five different EBV genotypes were found in two of nine individuals studied. These results support the hypothesis that multiple EBV infections of healthy individuals are common. The implications for the development of an EBV vaccine are discussed.Multiple Epstein-Barr virus (EBV) infections are common among immunocompromised individuals (21,29,31,39,41,43,44,46), but the origin of the multiple EBV strains remains a mystery. Multiple EBV strains could accumulate as superinfections in individuals who have lost previous protective immunity to EBV. Alternatively, they could represent the reactivation of latent EBV strains that were acquired prior to the onset of immunodeficiency. The reported prevalence of multiple EBV infections in healthy individuals ranges broadly between 0 and 100% (Table 1) (4,7,13,16,19,20,23,30,32,35,38,45; M. L. Lung and R. S. Chang, Letter, J. Infect. Dis. 162:994-995, 1990), but differences among these studies in the molecular detection and definition of an EBV strain confound the interpretation of their results.Molecular epidemiologic studies requiring EBV isolation by B-lymphocyte transformation (16,19,23,45; Lung and Chang, letter) suffer from selection bias toward transformation-competent EBV isolates (10,27,33). PCR amplification directly detects the EBV genome and avoids transformation selection bias, but the genetic definition of an EBV strain has been inconsistent across studies. Restriction fragment length polymorphisms detect either point mutations within restriction enzyme cleavage sites or variations of large repetitive regions within genome fragments (19,23,35; Lung and Chang, letter). Similarly, size variation in EBNA proteins ("EBNotype" or "EBNAprint") (16, 45) and size variation in specific gene PCR products (LMP-1, BZLF1, EBNA-6) (13, 35) reflect variations in repetitive and other genome sequences. However, many EBV genome sequences are susceptible to intrastrain homologous and nonhomologous recombination during productive replication and the number of repeat units present may vary in different isolates of the same EBV strain (12,38,(41)(42)(43). Studies examining the major sequence divergence between EBV types 1 and 2 have reported EBV coinfection rates ranging from 0 to 53% (4,13,20,34,35,45). However, EBV types 1 and 2 can both be further subdivided into different strains (1,24,41) and only three studies to date have utilized EBV gene nucleotide sequence variation to define EBV strains in healthy individuals (7,30,38).EBV genotyping assay. A consistent approach is needed for the definition and nomenclature of EBV genomes. It is impractical or even impossible to physically isolate (culture) and fully characterize the EBV genome(s) in clinical infections. A reasonable goal would be to identify an EBV genetic marker that represents the broad...

“…With the advent of the AIDS epidemic, oral hairy leukoplakia appeared, which was the first and remains the only disease caused entirely by productive replication of EBV. Oral hairy leukoplakia, which is an epithelial hyperplasia typically found on the lateral tongue (6), is full of and driven by EBV lytic replication (7,8). This bolstered the case for epithelial cells in the oral cavity being responsible for the production of cell-free virus in saliva, but still, normal epithelial cells were readily found to contain virus only in individuals coinfected with the human immunodeficiency virus (9).…”

Section: Early Workmentioning

confidence: 99%

The Long and Complicated Relationship between Epstein-Barr Virus and Epithelial Cells

Hutt-Fletcher

2017

The roles of epithelial cells in infection and persistence of the EpsteinBarr virus (EBV) have long been difficult to resolve. However, recent developments have reinforced the conclusion that these cells are a major site of virus replication and raised the possibility that, like papillomaviruses, EBV has evolved to take advantage of epithelial differentiation to ensure survival, persistence, and spread.KEYWORDS Epstein-Barr virus, epithelial cells, tropism E pstein-Barr virus (EBV) is well known as a human lymphotropic herpesvirus that was isolated from a Burkitt's lymphoma in the early 1960s (1). It is a well-described causal agent of infectious mononucleosis and an important player in the development of lymphoid tumors. It is well used as a tool for immortalizing human B cells. Soon after its discovery, an association between EBV and epithelial malignancies was revealed (2) and the presence of the virus was confirmed within epithelial cells of nasopharyngeal carcinoma (3). Yet, as late as 2005, a distinguished speaker at an international herpesvirus meeting declared that epithelial cells were not relevant to the general biology of EBV. How was that possible, and where are we today? EARLY WORKEarly works described EBV DNA and RNA in squamous epithelial cells shed in the oral cavity during acute infectious mononucleosis (4, 5). Thus, the model with B cells as the reservoir of latent EBV and epithelial cells as the site of productive lytic replication in vivo was developed. However, additional support for the routine involvement of epithelial cells in primary and persistent infections was, for many years, quite elusive. In the absence of any obvious lesions, such as those seen in herpes simplex infections, the finding of an infected cell in the oral cavity was much like looking for the proverbial needle in the haystack. Compounding the problem was the difficulty in infecting epithelial cells in vitro. With the advent of the AIDS epidemic, oral hairy leukoplakia appeared, which was the first and remains the only disease caused entirely by productive replication of EBV. Oral hairy leukoplakia, which is an epithelial hyperplasia typically found on the lateral tongue (6), is full of and driven by EBV lytic replication (7,8). This bolstered the case for epithelial cells in the oral cavity being responsible for the production of cell-free virus in saliva, but still, normal epithelial cells were readily found to contain virus only in individuals coinfected with the human immunodeficiency virus (9). For a while, the model of persistence pivoted toward the idea that in the absence of malignancy or other underlying disease, B cells alone are involved in infection (10).Three sets of observations subsequently helped spur a return to the yin-and-yang description of epithelial and B cell infection. Despite the uncertainty about the role of epithelial cells in EBV biology, its presence in epithelial cells of patients with nasopharyngeal carcinoma and gastric cancer indicates that EBV remains important for understanding...