Jennifer Tamblyn

The Epstein-Barr Virus-Encoded BILF1 Protein Modulates Immune Recognition of Endogenously Processed Antigen by Targeting Major Histocompatibility Complex Class I Molecules Trafficking on both the Exocytic and Endocytic Pathways

ABSTRACT Despite triggering strong immune responses, Epstein-Barr virus (EBV) has colonized more than 90% of the adult human population. Successful persistence of EBV depends on the establishment of a balance between host immune responses and viral immune evasion. Here we have extended our studies on the EBV-encoded BILF1 protein, which was recently identified as an immunoevasin that functions by enhancing degradation of major histocompatibility complex class I (MHC-I) antigens via lysosomes. We now demonstrate that disruption of the EKT signaling motif of BILF1 by a K122A mutation impairs the ability of BILF1 to enhance endocytosis of surface MHC-I molecules, while subsequent lysosomal degradation was impaired by deletion of the 21-residue C-terminal tail of BILF1. Furthermore, we identified another mechanism of BILF1 immunomodulation: it targets newly synthesized MHC-I/peptide complexes en route to the cell surface. Importantly, although the diversion of MHC-I on the exocytic pathway caused a relatively modest reduction in cell surface MHC-I, presentation of endogenously processed target peptides to immune CD8+ effector T cells was reduced by around 65%. The immune-modulating functions of BILF1 in the context of the whole virus were confirmed in cells lytically infected with a recombinant EBV in which BILF1 was deleted. This study therefore extends our initial observations on BILF1 to show that this immunoevasin can target MHC-I antigen presentation via both the exocytic and endocytic trafficking pathways. The results also emphasize the merits of including functional T cell recognition assays to gain a more complete picture of immunoevasin effects on the antigen presentation pathway.

Vitamin D, the placenta and early pregnancy: effects on trophoblast function

Pregnancy is associated with significant changes in vitamin D metabolism, notably increased maternal serum levels of active vitamin D, 1,25-dihydroxyvitamin (1,25(OH)2D). This appears to be due primarily to increased renal activity of the enzyme 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1) that catalyzes synthesis of 1,25(OH)2D, but CYP27B1 expression is also prominent in both the maternal decidua and fetal trophoblast components of the placenta. The precise function of placental synthesis of 1,25(OH)2D remains unclear, but is likely to involve localized tissue-specific responses with both decidua and trophoblast also expressing the vitamin D receptor (VDR) for 1,25(OH)2D. We have previously described immunomodulatory responses to 1,25(OH)2D by diverse populations of VDR-expressing cells within the decidua. The aim of the current review is to detail the role of vitamin D in pregnancy from a trophoblast perspective, with particular emphasis on the potential role of 1,25(OH)2D as a regulator of trophoblast invasion in early pregnancy. Vitamin D deficiency is common in pregnant women, and a wide range of studies have linked low vitamin D status to adverse events in pregnancy. To date, most of these studies have focused on adverse events later in pregnancy, but the current review will explore the potential impact of vitamin D on early pregnancy, and how this may influence implantation and miscarriage.

Decidual T Cells Exhibit a Highly Differentiated Phenotype and Demonstrate Potential Fetal Specificity and a Strong Transcriptional Response to IFN

Immune tolerance during human pregnancy is maintained by a range of modifications to the local and systemic maternal immune system. Lymphoid infiltration is seen at the implantation site of the fetal–maternal interface, and decidual NK cells have been demonstrated to facilitate extravillous trophoblast invasion into maternal decidua during the first trimester, optimizing hemochorial placentation. However, although there is considerable T cell infiltration of the maternal decidua, the functional properties of this T cell response remain poorly defined. We investigated the specificity and regulation of CD4+ and CD8+ T cells obtained from human third trimester decidua and demonstrated that decidual CD4+ and CD8+ T cells exhibit a highly differentiated effector memory phenotype in comparison with peripheral blood and display increased production of IFN-γ and IL-4. Moreover, decidual T cells proliferated in response to fetal tissue, and depletion of T regulatory cells led to an increase in fetal-specific proliferation. HY-specific T cells were detectable in the decidua of women with male pregnancies and were shown to be highly differentiated. Transcriptional analysis of decidual T cells revealed a unique gene profile characterized by elevated expression of proteins associated with the response to IFN signaling. These data have considerable importance both for the study of healthy placentation and for the investigation of the potential importance of fetal-specific alloreactive immune responses within disorders of pregnancy.

Vitamin D-deficiency and sex-specific dysregulation of placental inflammation

To investigate an immunomodulatory role for vitamin D in pregnancy we used mice raised on vitamin D-sufficient (SUFF), or -deficient (DEF) diets. At embryonic day 14, pregnant mice received intraperitoneal injection of lipopolysaccharide (LPS) or vehicle for 24h, with age-matched non-pregnant mice as controls. In non-pregnant mice, 6 serum analytes (IL-1β, IL-18, MDC/CCL22, MIP-1α/CCL3, EGF, IgA) were lower in DEF mice. In pregnant DEF mice only GH was higher. In non-pregnant mice LPS induced 28 analytes, with 5 (IL-18, IP-10/CXCL10, MCP-1/CCL2, MIP-1β/CCL4, MIP-3β/CCL19) being highest in DEF mice. In pregnant SUFF mice 16 serum analytes increased with LPS, and 6 of these (IP-10/CXCL10, MCP-1/CCL2, SAP, TIMP-1, VCAM-1, vWF) were higher and 1 (GCP-2/CXCL6) lower in DEF mice. Parallel analysis of placental mRNAs showed elevated mRNA for Il-6, Ccl2 and Cxcl10 in placentae from male and female fetuses in LPS-DEF mice. However, LPS-induced expression of Ifnγ, Tnfα, and Cxcl6 was only observed in female placentae from DEF mice. LPS-DEF mice also showed smaller litter sizes relative to control SUFF mice. Numbers of female fetuses per dam were significantly lower for DEF mice with or without LPS challenge. LPS had no effect on numbers of male fetuses from DEF mothers, but significantly decreased male fetuses from SUFF mothers. These data indicate that vitamin D is an important component of anti-inflammatory immune responses during pregnancy, with the placenta and fetal sex playing pivotal roles in this process.

Management of obstetric postpartum hemorrhage: a national service evaluation of current practice in the UK

Background Postpartum hemorrhage (PPH) continues to be one of the major causes of maternal mortality and morbidity in obstetrics. Variations in practice often lead to adverse maternity outcomes following PPH. Our objective was to assess the current practice in managing PPH in the UK. Methods We performed a national multicenter prospective service evaluation study over one calendar month and compared the current performance to national standards for managing PPH. We used a standardized data collection tool and collected data on patients’ demographics, incidence of PPH, estimated blood loss (EBL), prophylactic and treatment measures, onset of labor, and mode of delivery. Results We collected data from 98 obstetric units, including 3663 cases of primary PPH. Fifty percent of cases were minor PPH (EBL 500–1000 mL, n=1900/3613, 52.6%) and the remaining were moderate PPH (EBL >1000 to <2000 mL, n=1424/3613, 39.4%) and severe PPH (EBL >2000 mL, n=289/3613, 8%). The majority of women received active management of the third stage of labor (3504/3613, 97%) most commonly with Syntometrine intramuscular (1479/3613, 40.9%). More than half required one additional uterotonic agent (2364/3613, 65.4%) most commonly with Syntocinon intravenous infusion (1155/2364, 48.8%). There was a poor involvement of consultant obstetricians and anesthetists in managing PPH cases, which was more prevalent when managing major PPH (p=0.0001). Conclusion There are still variations in managing PPH in the UK against national guidelines. More senior doctor involvement and regular service evaluation are needed to improve maternal outcomes following PPH.

The role of ultrasound in fetal congenital myopathy detection: a novel case of fetal‐onset cap myopathy

Congenital myopathy (CM) is a rare heterogeneous group of neuromuscular disorders, the overall incidence of which is approximately 0.06 per 1000 live births. Greater than 40 individual subtypes of CM are now defined according to distinct pathological skeletal muscle features. Increasingly, genetic analysis is utilised to detect individual causative genes within CM subtypes. This accounts for the clinical variability in both disease severity and onset. For certain subtypes, a fetal-onset phenotype is recognised. Unlike the classically slowly progressive child and adult forms, a particularly rapid and severe disease course, with subsequent poorer prognosis is characteristic. Because no curative treatment currently exists, the outcome for fetal CM is invariably fatal. The principal aim of identifying CM prenatally is to enable informed parental counselling. Although recent advances in genetics and immunohistochemical myology suggest that mutant analysis is becoming increasingly realistic, testing remains primarily restricted to the postpartum setting. Prenatal CM detection subsequently remains reliant upon prospective detailed ultrasound (USS) evaluation. However, both the non-specific and heterogeneous nature of USS detectable features, along with associated polyhydramnios, has led to well described low levels of prospective detection in utero . Improving USS detection represents a key focus of current prenatal CM research. We report two sporadic cases of severe fetal-onset CM in order to highlight the key USS features and evaluate the literature regarding improved USS detection.

All for one and one for all : the value of grassroots collaboration in clinical research

Collaboration in health research is common in current practice. Engaging grassroots clinicians in the evidence synthesis and research process can deliver impactful results and reduce research wastage. The UKARCOG is a group of specialty trainees in obstetrics and gynaecology in the UK aiming to promote womens health research by delivering high-quality impactful research and national audit projects. The collaborative enables trainees to develop essential academic skills and roll out multicentre research projects at high cost-effectiveness. Collective research work can face a number of challenges such as establishing a joint authorship style, gaining institutional support and acquiring funds to boost networking and deliver large scales studies.