Stage-Specific Inhibition of MHC Class I Presentation by the Epstein-Barr Virus BNLF2a Protein during Virus Lytic Cycle

gamma-herpesvirus Epstein-Barr virus (EBV) persists for life in infected individuals despite the presence of a strong immune response. During the lytic cycle of EBV many viral proteins are expressed, potentially allowing virally infected cells to be recognized and eliminated by CD8+ T cells. We have recently identified an immune evasion protein encoded by EBV, BNLF2a, which is expressed in early phase lytic replication and inhibits peptide- and ATP-binding functions of the transporter associated with antigen processing. Ectopic expression of BNLF2a causes decreased surface MHC class I expression and inhibits the presentation of indicator antigens to CD8+ T cells. Here we sought to examine the influence of BNLF2a when expressed naturally during EBV lytic replication. We generated a BNLF2a-deleted recombinant EBV (ΔBNLF2a) and compared the ability of ΔBNLF2a and wild-type EBV-transformed B cell lines to be recognized by CD8+ T cell clones specific for EBV-encoded immediate early, early and late lytic antigens. Epitopes derived from immediate early and early expressed proteins were better recognized when presented by ΔBNLF2a transformed cells compared to wild-type virus transformants. However, recognition of late antigens by CD8+ T cells remained equally poor when presented by both wild-type and ΔBNLF2a cell targets. Analysis of BNLF2a and target protein expression kinetics showed that although BNLF2a is expressed during early phase replication, it is expressed at a time when there is an upregulation of immediate early proteins and initiation of early protein synthesis. Interestingly, BNLF2a protein expression was found to be lost by late lytic cycle yet ΔBNLF2a-transformed cells in late stage replication downregulated surface MHC class I to a similar extent as wild-type EBV-transformed cells. These data show that BNLF2a-mediated expression is stage-specific, affecting presentation of immediate early and early proteins, and that other evasion mechanisms operate later in the lytic cycle

Towards Endometriosis Diagnosis by Gadofosveset-Trisodium Enhanced Magnetic Resonance Imaging

Endometriosis is defined as the presence of endometrial tissue outside the uterus. It affects 10–15% of women during reproductive age and has a big personal and social impact due to chronic pelvic pain, subfertility, loss of work-hours and medical costs. Such conditions are exacerbated by the fact that the correct diagnosis is made as late as 8–11 years after symptom presentation. This is due to the lack of a reliable non-invasive diagnostic test and the fact that the reference diagnostic standard is laparoscopy (invasive, expensive and not without risks). High-molecular weight gadofosveset-trisodium is used as contrast agent in Magnetic Resonance Imaging (MRI). Since it extravasates from hyperpermeable vessels more easily than from mature blood vessels, this contrast agent detects angiogenesis efficiently. Endometriosis has high angiogenic activity. Therefore, we have tested the possibility to detect endometriosis non-invasively using Dynamic Contrast-Enhanced MRI (DCE-MRI) and gadofosveset-trisodium as a contrast agent in a mouse model. Endometriotic lesions were surgically induced in nine mice by autologous transplantation. Three weeks after lesion induction, mice were scanned by DCE-MRI. Dynamic image analysis showed that the rates of uptake (inwash), persistence and outwash of the contrast agent were different between endometriosis and control tissues (large blood vessels and back muscle). Due to the extensive angiogenesis in induced lesions, the contrast agent persisted longer in endometriotic than control tissues, thus enhancing the MRI signal intensity. DCE-MRI was repeated five weeks after lesion induction, and contrast enhancement was similar to that observed three weeks after endometriosis induction. The endothelial-cell marker CD31 and the pericyte marker α-smooth-muscle-actin (mature vessels) were detected with immunohistochemistry and confirmed that endometriotic lesions had significantly higher prevalence of new vessels (CD31 only positive) than the uterus and control tissues. The diagnostic value of gadofosveset-trisodium to detect endometriosis should be tested in human settings

Impaired leukocyte influx in cervix of postterm women not responding to prostaglandin priming

<p>Abstract</p> <p>Background</p> <p>Prolonged pregnancies are associated with increased rate of maternal and fetal complications. Post term women could be divided into at least two subgroups, one where parturition is possible to induce by prostaglandins and one where it is not. Our aim was to study parameters in cervical biopsies in women with spontaneous delivery at term (controls) and compare to those that are successfully induced post term (responders), and those that are not induced (non-responders), by local prostaglandin treatment.</p> <p>Methods</p> <p>Stromal parameters examined in this study were the accumulation of leukocytes (CD45, CD68), mRNAs and/or proteins for the extracellular matrix degrading enzymes (matrix metalloproteinase (MMP)-2, MMP-8 and MMP-9), their inhibitors (tissue inhibitor of MMP (TIMP)-1 and TIMP-2), interleukin-8 (IL-8), the platelet activating factor-receptor (PAF-R), syndecan-1 and estrogen binding receptors (estrogen receptor (ER)α, ERβ and G-coupled protein receptor (GPR) 30) as well as the proliferation marker Ki-67.</p> <p>Results</p> <p>The influx of leukocytes as assessed by CD45 was strongest in the responders, thereafter in the controls and significantly lower in the non-responders. IL-8, PAF-R and MMP-9, all predominantly expressed in leukocytes, showed significantly reduced immunostaining in the group of non-responders, while ERα and GPR30 were more abundant in the non-responders, as compared to the controls.</p> <p>Conclusion</p> <p>The impaired leukocyte influx, as reflected by the reduced number of CD45 positive cells as well as decreased immunostaining of IL-8, PAF-R and MMP-9 in the non-responders, could be one explanation of the failed ripening of the cervix in post term women. If the decreased leukocyte influx is a primary explanation to absent ripening or secondary, as a result of other factors, is yet to be established.</p

Directed Differentiation of Human Induced Pluripotent Stem Cells into Fallopian Tube Epithelium

Abstract The fallopian tube epithelium (FTE) has been recognized as a site of origin of high-grade serous ovarian cancer (HGSC). However, the absence of relevant in vitro human models that can recapitulate tissue-specific architecture has hindered our understanding of FTE transformation and initiation of HGSC. Here, induced pluripotent stem cells (iPSCs) were used to establish a novel 3-dimensional (3D) human FTE organoid in vitro model containing the relevant cell types of the human fallopian tube as well as a luminal architecture that closely reflects the organization of fallopian tissues in vivo. Modulation of Wnt and BMP signaling directed iPSC differentiation into Müllerian cells and subsequent use of pro-Müllerian growth factors promoted FTE precursors. The expression and localization of Müllerian markers verified correct cellular differentiation. An innovative 3D growth platform, which enabled the FTE organoid to self-organize into a convoluted luminal structure, permitted matured differentiation to a FTE lineage. This powerful human-derived FTE organoid model can be used to study the earliest stages of HGSC development and to identify novel and specific biomarkers of early fallopian tube epithelial cell transformation

Prevention and treatment of respiratory syncytial virus bronchiolitis and postbronchiolitic wheezing

<p>Abstract</p> <p>Respiratory syncytial virus (RSV) is the primary cause of hospitalization for acute respiratory tract illness in general and specifically for bronchiolitis in young children. The link between RSV bronchiolitis and reactive airway disease is not completely understood, even though RSV bronchiolitis is frequently followed by recurrent episodes of wheezing. Therapy with ribavirin does not appear to significantly reduce long-term respiratory outcome of RSV lower respiratory tract infection, and corticosteroid or bronchodilator therapy may possibly improve outcomes only on a short-term basis. No vaccine against RSV is yet available. It is not known whether prophylaxis with RSV intravenous immune globulin or palivizumab can reduce postbronchiolitic wheezing.</p