Phenotypic knock-out of the latent membrane protein 1 of Epstein-Barr virus by an intracellular single-chain antibody

Epstein-Barr virus (EBV) causes lymphoproliferative diseases in immunocompromised patients and is associated with endemic Burkitt lymphoma, nasopharyngeal carcinoma and some cases of Hodgkin disease. The latent membrane protein 1 (LMP1) of EBV is a transmembrane protein that is essential for the transformation of B lymphocytes. LMP1-mediated up-regulation of Bcl-2 is thought to be an important element in this process. As an approach to explore novel treatments for EBV-associated lymphomas, we constructed a single-chain antibody (sFv) directed against LMP1 to achieve functional inhibition of this oncoprotein in EBV-transformed B lymphocytes. We demonstrated that intracellular expression of an endoplasmic reticulum (ER)-targeted form of this sFv markedly reduced LMP1 protein levels. We also observed a decrease in intracellular level of this protein which correlated with a marked reduction of Bcl-2 expression in EBV-transformed B lymphocytes. We further demonstrated that anti-LMP1 sFv-mediated reduction of Bcl-2 correlated with increased sensitivity of these cells to drug-induced cell death. Therefore, these data suggest that an anti-LMP1 sFv used in combination with conventional chemotherapy may be useful for gene therapy of EBV-associated lymphomas in immunocompromised patients.     

Defensiveness, trait anxiety, and Epstein-Barr viral capsid antigen antibody titers in healthy college students.

Investigated the relationship of individual differences in repressive coping styles with differences in antibody titer to Epstein-Barr (EB) viral capsid antigen in a normal, healthy college population made up of people previously exposed to EB. Each of 54 1st-yr undergraduates completed a battery of physical-status questions and items pertaining to potential behavioral immunomodulatory confounds, along with the Taylor Manifest Anxiety Scale and the Marlowe-Crowne Social Desirability Scale. Ss reporting high and middle levels of anxiety had higher antibody titers to EB, suggesting poorer immune control over the latent virus, as compared with the low-anxious group. Similarly, high-defensive Ss had higher antibody titers than their low-defensive counterparts, and neither group differed from the middle group. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequence requirements of the Epstein-Barr virus latent origin of DNA replication

The Epstein-Barr virus (EBV) latent origin of DNA replication (oriP) is composed of two elements that contain binding sites for the sole viral gene product required for latent cycle replication, EBNA-1. One of these elements, region I, functions as an EBNA-1-dependent enhancer for RNA polymerase II-transcribed genes, may play a role in plasmid segregation, and is required for origin function in B cells latently infected with EBV. The second element, region II, contains or is very near the site of initiation of DNA replication. A genetic approach was taken to determine the contribution of the EBNA-1 binding sites in oriP to origin function. Although region I is required for the transient replication of plasmids bearing region II in EBV-infected B cells, a plasmid lacking region I but containing region II, was observed to replicate transiently in both D98/Raji and HeLa cells expressing EBNA-1. Thus, binding of EBNA-1 to region I is not absolutely required for the molecular events that lead to initiation of DNA replication at region II. Site-directed mutagenesis of the four EBNA-1-binding sites in region II, individually and in various combinations, demonstrated that only two EBNA-1-binding sites are required for region II function. The results obtained with these mutants, together with the analysis of the replicative ability of plasmids containing insertions between EBNA-1-binding sites, suggested that the spatial relationship of the two sites is critical. Mutants that contain only two EBNA-1-binding sites separated by 26 to 31 bp in region II were not maintained as plasmids over many cell generations and were greatly reduced in their ability to replicate transiently in D98/Raji cells. The EBNA-1-induced bending or untwisting of the DNA in EBNA-1-binding sites 1 and 4 in region II did not, however, demonstrate this spatial constraint. It may be concluded from these results that specific protein-protein interactions between EBNA-1 and/or between EBNA-1 and a cellular protein(s) are required for origin function.     

Emotional expression modulates perceived gaze direction.

Gaze perception is an important social skill, as it portrays information about what another person is attending to. Gaze direction has been shown to affect interpretation of emotional expression. Here the authors investigate whether the emotional facial expression has a reciprocal influence on interpretation of gaze direction. In a forced-choice yes-no task, participants were asked to judge whether three faces expressing different emotions (anger, fear, happiness, and neutral) in different viewing angles were looking at them or not. Happy faces were more likely to be judged as looking at the observer than were angry, fearful, or neutral faces. Angry faces were more often judged as looking at the observer than were fearful and neutral expressions. These findings are discussed on the background of approach and avoidance orientation of emotions and of the self-referential positivity bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Epstein-Barr virus latent membrane protein-1 oncogene deletion in post-transplantation lymphoproliferative disorders

Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) is a multifunctional oncoprotein. A 30-bp deletion of the 3' end of the LMP1 gene (del-LMP1) has been identified in some EBV isolates. This deleted LMP1 gene encodes a protein, altered on the carboxy terminus, which is thought to have greater oncogenic potential than the wild type. Recently, it was suggested that del-LMP1 plays a role in the development of malignant lymphomas occurring in immunocompromised patients. To further elucidate the role of del-LMP1 in post-transplantation lymphoproliferative disorders (PT-LPDs) we analyzed 58 PT-LPD lesions from 36 heart and kidney organ transplant recipients. Overall, del-LMP1 was detected in 44% of the cases. Four plasmacytic hyperplasias (36%), eight polymorphic B-cell hyperplasias/polymorphic B-cell lymphomas (38%), and five malignant lymphomas/multiple myelomas (71%) exhibited del-LMP1. Two of the three patients displaying disease progression showed wild-type LMP1 gene (w-LMP1) and one showed del-LMP1. LMP1 status remained the same in all three patients during disease progression. In patients undergoing biopsy of multiple separate PT-LPD lesions representing different clonal lymphoid proliferations, LMP1 status was the same in all of the lesions in each patient. Furthermore, although the polyclonal lesions harbor multiple EBV infectious events, they either showed w- or del-LMP1 but not both. Analysis of the tissues without an apparent PT-LPD (peripheral blood, bone marrow, or colon) revealed EBV and LMP1 type identical to that found in the lesions. In conclusion, the presence or absence of del-LMP1 in PT-LPDs does not correlate with the histopathological category or the malignant nature of the lymphoid proliferation. LMP1 status does not change during disease progression and is the same within multiple lesions occurring in the same patient regardless of their clonal relationship. These findings suggest that 1) EBV infection in patients with PT-LPDs occurs with a w- or del-LMP1-type EBV isolate and does not change once a patient acquires the virus and 2) the infection is an early event in the development of PT-LPDs and transformation is induced regardless of the type of LMP1.     

Emotional disclosure about traumas and its relation to health: Effects of previous disclosure and trauma severity.

[Correction Notice: An erratum for this article was reported in Vol 63(2) of Journal of Personality and Social Psychology (see record 2008-10509-001). In the article, a sentence was incorrect. The corrected sentence is included in the erratum.] Sought to replicate previous findings that disclosing traumas improves physical health and to compare the effects of revealing previously disclosed vs undisclosed traumas. According to inhibition theory, reporting about undisclosed traumas should produce greater health benefits. 60 healthy undergraduates wrote about undisclosed traumas, previously disclosed traumas, or trivial events. Contrary to expectations, there were no significant between-groups differences on longer term health utilization and physical symptom measures. However, Ss who disclosed more severe traumas reported fewer physical symptoms in the months following the study, compared with low-severity trauma Ss, and tended to report fewer symptoms than control Ss. Results suggest that health benefits occur when severe traumas are disclosed, regardless of whether previous disclosure has occurred. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of IgG antibody to Epstein-Barr virus viral capsid antigen in saliva by antibody capture radioimmunoassay

In order to characterize the cochlear transducer nonlinearities which are involved in the generation of the summating potential (SP), we investigated the effect of a change in the electrical operating point of the cochlear transducer on the SP. The electrical operating point of the cochlear transducer was affected by suppressing reversibly the endocochlear potential (EP). This was realized by intravenous injection of furosemide in guinea pig. A differential recording technique was used in the basal turn of the cochlea to measure locally generated even-order distortion products: the SP and the second harmonic component (2F0) of the cochlear microphonics (CM). These potentials were evoked by 2 and 8 kHz stimuli presented at 60 dB SPL. Following furosemide injection, the SP changed polarity twice over time. The zero crossings of the SP coincided with a minimum in the amplitude of 2F0. Concomitantly, the phase of 2F0 shifted about 120 degrees. The changes in the electrical even-order products were comparable to the changes that occurred in a mechanical even-order intermodulation distortion product (the difference tone F2-F1 otoacoustic emission) after furosemide application (Mills et al., J. Acoust. Soc. Am. 94 (1993) 2108-2122). The combined results suggest that only one sigmoidal transfer function may account for the SP, 2F0, and the emission of the difference tone F2-F1, and that shifts in the operating point of the transfer function would be the major cause behind the furosemide-induced changes in the even-order distortion products. The sigmoidal transfer function is likely associated with the mechano-electrical transducer channel at the apical pole of the outer hair cell.     

The Epstein-Barr virus latent membrane protein 1 induces expression of the epidermal growth factor receptor

The Epstein-Barr virus (EBV)-encoded LMP1 protein is an important component of the process of transformation by EBV. LMP1 is essential for transformation of B lymphocytes, most likely because of its profound effects on cellular gene expression. Although LMP1 is expressed in the majority of nasopharyngeal carcinoma (NPC) tumors, the effect of LMP1 on cellular gene expression and its contribution to the development of malignancy in epithelial cells is largely unknown. In this study the effects of LMP1 on the expression and tyrosine kinase activity of the epidermal growth factor receptor (EGFR) were investigated in C33A human epithelial cells. Stable or transient expression of LMP1 in C33A cells increased expression of the EGFR at both the protein and mRNA levels. In contrast, expression of the EGFR was not induced by LMP1 in EBV-infected B lymphocytes. Stimulation of LMP1-expressing C33A cells with epidermal growth factor (EGF) caused rapid tyrosine phosphorylation of the EGFR (pp170) as well as several other proteins, including pp120, pp85, pp75, and pp55, indicating that the EGFR induced by LMP1 is functional. LMP1 also induced expression of the A20 gene in C33A epithelial cells. In C33A cells, LMP1 expression increased the proliferative response to EGF, as LMP1-expressing C33A cells continued to increase in number when plated in serum-free media supplemented with EGF, while the neo control cells exhibited very low levels of viability and did not proliferate. Immunoblot analysis of protein extracts from nude mouse-passaged NPC tumors also demonstrated that the EGFR is overexpressed in primary NPC tumors as well as those passaged in nude mice. This study suggests that the alteration in the growth patterns of C33A cells expressing LMP1 is a result of increased proliferative signals due to enhanced EGFR expression, as well as protection from cell death due to LMP1-induced A20 expression. The induction of EGFR and A20 by LMP1 may be an important component of EBV infection in epithelial cells and could contribute to the development of epithelial malignancies such as NPC.     

Encephalomyeloradiculopathy associated with Epstein-Barr virus: primary infection or reactivation?

INTRODUCTION: Encephalomyeloradiculopathy (EMR) is a new syndrome, characterized by extensive involvement of the nervous system at different levels, including brain, medulla and spinal roots. We describe a patient presenting with prodromal febrile illness, followed by a wide infection of the nervous system with transverse myelitis and less severe meningitis, encephalitis and polyradiculopathy. The patient was treated with high-dose corticosteroids, antibiotics and acyclovir; in spite of therapy his condition improved very slowly, with severe neurological sequelae. MATERIAL AND METHODS: Antiviral antibodies were searched for in serum and cerebrospinal fluid (CSF) by commercially available ELISA kits. Viral investigations were performed by cell culture isolation and search for viral antigens, and genomic nucleic acids were investigated by polymerase chain reaction (PCR). RESULTS: Virological and serological studies evidenced a primary infection by cytomegalovirus (CMV), possibly responsible for the prodromal illness, persisting in the course of the disease. PCR performed in the peripheral blood mononuclear cells (PBMCs), DNA collected early and in the CSF drawn 30 days after the onset of the disease showed Epstein-Barr virus (EBV) DNA. The serum panel of EBV antibodies was typical of an intercurrent virus reactivation, more than of a primary infection. CONCLUSION: EBV is known to be highly infectious for the nervous system, in this case of EMR the presence of DNA sequences in the PBMCs and CSF suggests that EBV plays a role in the development of this newly described syndrome.     

Epstein-Barr virus strain type and latent membrane protein 1 gene deletions in lymphomas in patients with rheumatic diseases

We have previously shown that long-term angiotensin-converting enzyme (ACE) inhibition prevents the increase in aortic collagen in spontaneously hypertensive rats (SHRs), independent of blood pressure reduction. More recently, we reported that the effects of ACE inhibition in the prevention of aortic collagen accumulation were related to the inhibition of angiotensin II actions on angiotensin II type 1 receptors. Aldosterone, the synthesis of which is mainly modulated by angiotensin II through type 1 receptor stimulation, is known to promote cardiac fibrosis in different experimental models. The aim of the present study was to determine whether inhibition of aldosterone formation was able to prevent aortic fibrosis in SHRs. For this purpose, we compared the effects of a 4-month treatment with the aldosterone antagonist spironolactone with the ACE inhibitor quinapril in 4-week-old SHRs. Control SHRs and Wistar-Kyoto (WKY) rats received placebo for the same period of time. At the end of treatment, in conscious SHRs vs WKY controls, quinapril completely prevented the development of hypertension, whereas spironolactone produced only a slight but significant reduction in blood pressure. Aortic hypertrophy was significantly prevented by ACE inhibition but not by spironolactone. On the contrary, aortic collagen accumulation was completely prevented by both quinapril and spironolactone. In the latter case, collagen density was significantly below that of WKY controls. These results show that in SHRs, spironolactone can markedly prevent aortic fibrosis in the presence of a very slight antihypertensive effect. It is suggested that ACE inhibition or type 1 receptor antagonist-induced prevention of aortic collagen accumulation is at least partially related to aldosterone inhibition.     

Emotional and physical intimacy in coping with lupus: Women's dilemmas of disclosure and approach.

This study examined whether self-rated physical and emotional intimacy of 74 women with their heterosexual partner, during an illness episode of lupus, was related to their affect and relationship satisfaction. It was predicted that greater intimacy would be related to better psychosocial adjustment. Women who engaged in physically intimate behavior with their partner more often reported greater relationship satisfaction. Women who frequently avoided or who were often the initiators of physical intimacy, however, reported greater negative affect. Concerning emotional intimacy, women who disclosed more information about illness symptoms and women who concealed more information about their symptoms and feelings experienced the highest levels of negative affect. Results identify dilemmas that women with recurrent illness may face when trying to maintain intimacy during illness periods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)