Fred Wang

Induction of bcl-2 expression by epstein-barr virus latent membrane protein 1 protects infected B cells from programmed cell death

Epstein-Barr virus (EBV) not only induces growth transformation in human B lymphocytes, but has more recently been shown to enhance B cell survival under suboptimal conditions where growth is inhibited; both effects are mediated through the coordinate action of eight virus-coded latent proteins. The effect upon cell survival is best recognized in EBV-positive Burkitts lymphoma cell lines where activation of full virus latent gene expression protects the cells from programmed cell death (apoptosis). Here we show by DNA transfection into human B cells that protection from apoptosis is conferred through expression of a single EBV latent protein, the latent membrane protein LMP 1. Furthermore, we demonstrate that LMP 1 mediates this effect by up-regulating expression of the cellular oncogene bcl-2. The interplay between EBV infection and expression of this cellular oncogene has important implications for virus persistence and for the pathogenesis of virus-associated malignant disease.

Complete Nucleotide Sequence of the Rhesus Lymphocryptovirus: Genetic Validation for an Epstein-Barr Virus Animal Model

ABSTRACT We sequenced the rhesus lymphocryptovirus (LCV) genome in order to determine its genetic similarity to Epstein-Barr virus (EBV). The rhesus LCV encodes a repertoire identical to that of EBV, with 80 open reading frames, including cellular interleukin-10, bcl-2, and colony-stimulating factor 1 receptor homologues and an equivalent set of viral glycoproteins. The highly conserved rhesus LCV gene repertoire provides a unique animal model for the study of EBV pathogenesis.

Congenital Dacryocele: A Collaborative Review

Fifty-four cases of congenital dacryocele from several medical centers were reviewed retrospectively. There was strong female preponderance (73%) and unilateral involvement (88%). Lacrimal sac contents could be expressed by local massage through the puncta in 21% of cases. Probing and irrigation were done under general (27.8%) or local (55.6%) anesthesia, while in other cases (16.7%), the cyst resolved before intervention. Recurrence of the dacryocele occurred in 10 patients (22%) after probing. Nasal cysts were visualized in six cases. Marsupialization of nasal cysts was necessary in four cases. In one center, after conservative therapy, 80% of cysts resolved spontaneously and 20% developed dacryocystitis. Surgical intervention is indicated in cases of dacryocystitis, cellulitis, breathing difficulty from large nasal cysts, recurrent dacryocele, and lack of its resolution after a short trial of digital massage.

Complete Genomic Sequence of an Epstein-Barr Virus-Related Herpesvirus Naturally Infecting a New World Primate: a Defining Point in the Evolution of Oncogenic Lymphocryptoviruses

ABSTRACT Callitrichine herpesvirus 3 (CalHV-3) was isolated from a B-cell lymphoma arising spontaneously in the New World primate Callithrix jacchus, the common marmoset. Partial genomic sequence analysis definitively identified CalHV-3 as a member of the Epstein-Barr virus (EBV)-related lymphocryptovirus (LCV) genus and extended the known host range of LCVs beyond humans and Old World nonhuman primates. We have now completed the first genomic sequence of an LCV infecting a New World primate by describing the unique short region, the major internal repeat, and a portion of the unique long region. This portion of the genome contains the putative latent origin of replication and 13 additional open reading frames (ORFs), 5 of which show no homology to any viral or cell genes. One of the novel genes, C5, is a positional homologue for the transformation-essential EBV gene EBNA-2. The marmoset LCV genome is also notable for the absence of viral interleukin-10 and small nonpolyadenylated RNA homologues. Marmoset LCV transcripts encoding putative latent infection nuclear proteins have a common leader sequence that is spliced from the major internal repeat in a manner similar to that of the EBV EBNA-LP, suggesting strong conservation of a common promoter and splicing of these latent infection mRNAs. An EBV LMP2A-like spliced transcript crossing the terminal repeats encodes a unique ORF, C7, with multiple transmembrane domains and tyrosine kinase phosphorylation sites functionally reminiscent of EBV LMP2A. However, the carboxy-terminal location of the candidate phosphotyrosine residues is more reminiscent of the Kaposis sarcoma-associated herpesvirus K15 gene and provides potential evidence of an evolutionary transition from rhadinoviruses to lymphocryptoviruses. The unusual gene repertoire of the marmoset LCV differentiates ancestral viral genes likely present in an LCV progenitor from viral genes acquired later as primates and LCV coevolved, providing a defining point in the evolution of oncogenic LCVs.

Sequence and Functional Analysis of EBNA-LP and EBNA2 Proteins from Nonhuman Primate Lymphocryptoviruses

ABSTRACT The Epstein-Barr virus (EBV) EBNA-LP and EBNA2 proteins are the first to be synthesized during establishment of latent infection in B lymphocytes. EBNA2 is a key transcriptional regulator of both viral and cellular gene expression and is essential for EBV-induced immortalization of B lymphocytes. EBNA-LP is also important for EBV-induced immortalization of B lymphocytes, but far less is known about the functional domains and cellular cofactors that mediate EBNA-LP function. While recent studies suggest that serine phosphorylation of EBNA-LP and coactivation of EBNA2-mediated transactivation are important, more detailed mutational and genetic studies are complicated by the repeat regions that comprise the majority of the EBNA-LP sequence. Therefore, we have used a comparative approach by studying the EBNA-LP homologues from baboon and rhesus macaque lymphocryptoviruses (LCVs) (baboon LCV and rhesus LCV). The predicted baboon and rhesus LCV EBNA-LP amino acid sequences are 61 and 64% identical to the EBV EBNA-LP W1 and W2 exons and 51% identical to the EBV EBNA-LP Y1 and Y2 exons. Five evolutionarily conserved regions can be defined, and four of eight potential serine residues are conserved among all three EBNA-LPs. The major internal repeat sequence also revealed a highly conserved Wp EBNA promoter with strong conservation of upstream activating sequences important for Wp transcriptional regulation. To test whether transcriptional coactivating properties were common to the rhesus LCV EBNA-LP, a rhesus LCV EBNA2 homologue was cloned and expressed. The rhesus LCV EBNA2 transcriptionally transactivates EBNA2-responsive promoters through a CBF1-dependent mechanism. The rhesus LCV EBNA-LP was able to further enhance rhesus LCV or EBV EBNA2 transactivation 5- to 12-fold. Thus, there is strong structural and functional conservation among the simian EBNA-LP homologues. Identification of evolutionarily conserved serine residues and regions in EBNA-LP homologues provides important clues for identifying the cellular cofactors and molecular mechanisms mediating these conserved viral functions.

Major reviewOcular choristomas

Choristomas are congenital lesions representing normal tissue(s) in an abnormal location. They are the most common epibulbar and orbital tumors in children. Epibulbar choristomas affect the cornea, limbus or subconjunctival space, and range in appearance from a small, flat lesion to a large mass filling most of the epibulbar region. Astigmatism is often present. Choristomas may be associated with coloboma, Goldenhar syndrome or epidermal nevus syndromes; those associated with the latter are often bilateral and extensive. Choristomas are occasionally familial. Surgery may be indicated to improve vision or cosmesis, or to impede growth. Although choristomas most commonly involve the epibulbar area, they can affect many areas of the eye and orbit, and often affect more than one area.

Differential Targeting and Shifts in the Immunodominance of Epstein‐Barr Virus–Specific CD8 and CD4 T Cell Responses during Acute and Persistent Infection

The evolution of Epstein-Barr virus (EBV)-specific T cell responses that occurs during the acute and persistent stages of infection remains poorly characterized despite its importance for developing immune interventions for EBV-associated disorders. This study assessed T cell responses to 113 EBV-derived epitopes in 40 subjects with acute or persistent EBV infection. Although no significant differences were seen in the breadth of CD8 and CD4 T cell responses, their magnitude differed significantly over time; acutely infected subjects generated especially strong responses to lytic viral antigens. The cross-sectional shift in immunodominance was also confirmed in subjects followed longitudinally from acute to persistent infection. In addition, human leukocyte antigen-matched siblings with discordant histories of symptomatic EBV infection showed no significant differences in their response patterns, suggesting that symptomatic EBV infection does not lead to unique persistent-stage responses. These data provide an assessment of immunodominance patterns and guidance for developing immunotherapeutic interventions for EBV-associated disorders.

Direct Relationship between Suppression of Virus-Specific Immunity and Emergence of Cytomegalovirus Disease in Simian AIDS

ABSTRACT Although opportunistic infections like cytomegalovirus (CMV) are common sequelae of end-stage AIDS, the immune events leading to CMV reactivation in human immunodeficiency virus (HIV)-infected individuals are not well defined. The role of cellular and humoral CMV-specific immune responses in immune control of latent CMV infection was evaluated prospectively in a cohort of 11 simian immunodeficiency virus (SIV)-infected CMV-seropositive rhesus macaques, 6 of whom had histologic evidence of CMV disease at death. Macaques with CMV disease differed from macaques without CMV disease in having significantly higher levels of plasma SIV RNA and CMV DNA and significantly lower titers of anti-CMV binding antibodies (Abs) at the time of death. A significant decline in anti-CMV Abs and CMV-specific CD4+ and CD8+ T lymphocytes over time was observed in the macaques with CMV disease, but not in the macaques without CMV disease. Reduction in CMV-specific CD8+ T lymphocytes and anti-CMV neutralizing Abs was significantly correlated with a decline in CMV-specific CD4+ T lymphocytes. Although declines in CMV-specific T lymphocytes alone were sufficient for reactivation of low-level CMV viremia, high-level viremia (>1,000 copies of CMV DNA per ml of plasma) was observed when anti-CMV neutralizing and binding Abs had also declined. Thus, the occurrence of CMV reactivation-associated disease in AIDS is associated with suppression of both cellular and humoral CMV-specific immune responses. The underlying mechanism may be a dysfunction of memory B and CD8+ T lymphocytes associated with SIV-induced impairment of CMV-specific CD4+ T-cell help.

Ocular Findings in the Facioauriculovertebral Sequence (Goldenhar-Gorlin Syndrome)

We reviewed the ocular findings in 57 consecutive patients with the facioauriculovertebral sequence (Goldenhar-Gorlin syndrome). Epibulbar choristomas were detected in 18 cases (32%), a much lower occurrence than reported previously. Various motility disorders (11 cases, 19%), blepharoptosis or narrow palpebral fissures (seven cases, 12%), eyelid colobomas (six cases, 11%), and lacrimal drainage system anomalies (six cases, 11%) were more frequent than previously noted. These ocular findings were more common in the patients with epibulbar choristomas. Of the various features of the Goldenhar-Gorlin syndrome (skin tags, microtia, hemifacial microsomia, and vertebral anomalies), only skin tags correlated positively with the laterality of epibulbar choristomas. Preauricular and facial tags represent choristomas, explaining their association with epibulbar choristomas and the laterality they share.

Genomic Sequence of Rhesus Cytomegalovirus 180.92: Insights into the Coding Potential of Rhesus Cytomegalovirus

ABSTRACT A pathogenic isolate of rhesus cytomegalovirus (rhCMV 180.92) was cloned, sequenced, and annotated. Comparisons with the published rhCMV 68.1 genome revealed 8 open reading frames (ORFs) in isolate 180.92 that are absent in 68.1, 10 ORFs in 68.1 that are absent in 180.92, and 34 additional ORFs that were not previously annotated. Most of the differences appear to be due to genetic rearrangements in both isolates from a region that is frequently altered in human CMV (hCMV) during in vitro passage. These results indicate that the rhCMV ORF repertoire is larger than previously recognized. Like hCMV, understanding of the complete coding capacity of rhCMV is complicated by genomic instability and may require comparisons with additional isolates in vitro and in vivo.