Functional significance of CD4+ and CD8+ T lymphocytes in the immune response to murine gammaherpesvirus 68

Murine gammaherpesvirus 68 (MHV-68) is a natural pathogen of murid rodents and is closely related to Human Herpesvirus 8, Herpesvirus saimiri and Epstein Barr virus. Intranasal infection of inbred mouse strains with MHV-68 results in the lungs of these animals becoming productively infected with virus. In immunocompetent mice, MHV-68 is cleared from the lungs by day 10 after infection. By this time the virus has reached the spleen and has adopted a latent form of infection in B lymphocytes. Depletion of CD8+ T cells from mice, prior to infection, results in uncontrolled MHV-68 replication in the lungs and death of the animal by day 12 post-infection. Such evidence indicates that CD8+ T cells play an important role in the immune response of mice to primary infection with MHV-68.In this study T lymphocyte responses to MHV-68 were examined in vitro and in vivo.In vitro work focused on developing a conventional assay to measure MHV-68-specific CTL activity. It was found that splenocytes from MHV-68-infected mice consistently lysed 'S11' cells, a B cell lymphoma line originally isolated from an MHV-68-infected mouse. All S11 cells are latently infected with MHV-68 and around 5% of these cells support viral replication. Treatment of S11 cells with the anti-viral drug, 4'- S-EtdU, is known to prevent lytic MHV-68 protein expression. 4'-S-EtdU-treated S11 target cells were killed by lymphocytes from infected mice. This indicates that the T lymphocytes responsible for killing S11 cells were specific for a latent antigen of MHV-68. No measurable cytolytic activity against any other target cell line, infected in vitro with MHV-68, was detected.S11 has been shown to divide and expand when implanted subcutaneously into nude (T cell-deficient) mice. S11 does not expand when implanted into normal, immunocompetent mice, implying that T lymphocytes play a key role in inhibiting tumour formation. To investigate this theory, S11 cells were injected subcutaneously into nude mice. This was followed by transfer of re-stimulated lymphocyte populations, enriched for either CD4+ or CD8+ T cells, into the animals. This protocol consistently resulted in regression of S11 tumours. Splenocyte populations depleted of CD8+ T lymphocytes were most effective in preventing tumour formation. This suggests that CD4+ T cells play a major role in preventing B cell lymphoma outgrowth. Immunohistochemical analyses highlighted populations of macrophages and CD4+ T cells in regressing tumours. It may be hypothesised that CD4+ T cells elicit tumour regression via the initiation of a delayed-type hypersensitivity (DTH) response.Further in vivo work involved depleting BALB/c mice T lymphocyte subsets (CD4 and CD8) at a range of times before or after MHV-68 infection. Subsequently, virus titre in the lungs was assessed by plaque assay. Latently-infected B cells in the spleen were quantified by infectious centre assay and visualised by in situ hybridisation. Using these techniques it was demonstrated that both CD4+ and CD8+ T lymphocytes contribute to clearance of MHV-68 from the lungs. CD8+ T cells also appear to limit the extent of B lymphocyte infection in the spleen. However, CD8+ T cells do not appear to be responsible for the decline in latently infected B cells which occurs in MHV-68 infected mice 2 to 3 weeks after infection.In conclusion, MHV-68 infection of inbred laboratory mouse strains has potential to model immunological responses to primary gammaherpesvirus infection in humans. In addition, histopathology induced by the S11 cell line implanted into nude mice could provide insight into gammaherpesvirus-associated B lymphoproliferative disease in immunocompromised individuals

Sub-system mechanical design for an eLISA optical bench

We present the design and development status of the opto-mechanical sub-systems that will be used in an experimental demonstration of imaging systems for eLISA. An optical bench test bed design incorporates a Zerodur® baseplate with lenses, photodetectors, and other opto-mechanics that must be both adjustable - with an accuracy of a few micrometers - and stable over a 0 to 40°C temperature range. The alignment of a multi-lens imaging system and the characterisation of the system in multiple degrees of freedom is particularly challenging. We describe the mechanical design of the precision mechanisms, including thermally stable flexure-based optical mounts and complex multi-lens, multi-axis adjuster mechanisms, and update on the integration of the mechanisms on the optical bench

Bis(μ-disulfur dinitrido)bis­[diphenyl­tin(IV)]

The title compound, [Sn2(C6H5)4(N2S2)2], exists as a centrosymmetric binuclear dimer with the SnIV centres in distorted trigonal bipyramidal geometry and a central Sn2N2 core

Epidemiology and Phylogenetic Analysis of Viral Respiratory Infections in Vietnam.

Acute respiratory infections (ARIs) impose a major public health burden on fragile healthcare systems of developing Southeast Asian countries such as Vietnam. The epidemiology, genetic diversity and transmission patterns of respiratory viral pathogens that circulate in this region are not well characterized. We used RT-PCR to screen for 14 common respiratory viruses in nasal/throat samples from 4326 ARI patients from 5 sites in Vietnam during 2012-2016. 64% of patients tested positive for viruses; 14% tested positive multiple co-infecting viruses. The most frequently detected viruses were Respiratory syncytial virus (RSV, 23%), Human Rhinovirus (HRV, 13%), Influenza A virus (IAV, 11%) and Human Bocavirus (HBoV, 7%). RSV infections peaked in July to October, were relatively more common in children 5 years in the central region. Coinfection with IAV or RSV was associated with increased disease severity compared with patients only infected with HBoV or HRV. Over a hundred genomes belonging to 13 families and 24 genera were obtained via metagenomic sequencing, including novel viruses and viruses less commonly associated with ARIs. Phylogenetic and phylogeographic analyses further indicated that neighboring countries were the most likely source of many virus lineages causing ARIs in Vietnam and estimated the period that specific lineages have been circulating. Our study illustrates the value of applying the state-of-the-art virus diagnostic methods (multiplex RT-PCR and metagenomic sequencing) and phylodynamic analyses at a national level to generate an integrated picture of viral ARI epidemiology

The Burden of Revision Sinonasal Surgery in the UK – Data from the Chronic Rhinosinusitis Epidemiology Study (CRES); a cross sectional study

Objectives/Hypothesis The aim of this study was to investigate the surgical revision rate in patients with Chronic Rhinosinusitis (CRS) in the UK CRS Epidemiology Study (CRES). Previous evidence from national Sinonasal Audit showed that 1459 CRS patients demonstrated a surgical revision rate 19.1% at 5 years, with highest rates seen in those with polyps (20.6%). Setting Thirty secondary care centres around the UK. Participants A total of 221 controls and 1249 patients with CRS were recruited to the study including those with polyps (CRSwNPs), without polyps (CRSsNPs) and with allergic fungal rhinosinusitis (AFRS). Interventions Self-administered questionnaire. Primary outcome measure The need for previous sinonasal surgery. Results A total of 651 patients with CRSwNPs, 553 with CRSsNPs and 45 with AFRS were included. A total of 396 (57%) of patients with CRSwNPs/AFRS reported having undergone previous endoscopic nasal polypectomy (ENP), of which 182 of the 396 (46%) reported having received more than one operation. The mean number of previous surgeries per patient in the revision group was 3.3 (range 2 to 30) and a mean duration of time of 10 years since the last procedure. The average length of time since their first operation up to inclusion in the study was 15.5 years (range 0-74). Only 27.9% of all patients reporting a prior ENP had received concurrent endoscopic sinus surgery (ESS) (n=102). For comparison, surgical rates in patients with CRSsNPs were significantly lower; 13% of cases specifically reported ESS and of those only 30% reported multiple procedures (chi-squared p < 0.001). Conclusions This study demonstrated there is a high burden of both primary and revision surgery in patients with CRS, worst in those with AFRS and least in those with CRSsNPs. The burden of revision surgery appears unchanged in the decade since the Sinonasal Audit

B-Methylated Amine-Boranes:Substituent Redistribution, Catalytic Dehydrogenation, and Facile Metal-Free Hydrogen Transfer Reactions

Although the dehydrogenation chemistry of amine-boranes substituted at nitrogen has attracted considerable attention, much less is known about the reactivity of their B-substituted analogues. When the B-methylated amine-borane adducts, RR′NH·BH₂Me (<b>1a</b>: R = R′ = H; <b>1b</b>: R = Me, R′ = H; <b>1c</b>: R = R′ = Me; <b>1d</b>: R = R′ = <i>i</i>Pr), were heated to 70 °C in solution (THF or toluene), redistribution reactions were observed involving the apparent scrambling of the methyl and hydrogen substituents on boron to afford a mixture of the species RR′NH·BH_3–<i>x</i>Me_<i>x</i> (<i>x</i> = 0–3). These reactions were postulated to arise via amine-borane dissociation followed by the reversible formation of diborane intermediates and adduct reformation. Dehydrocoupling of <b>1a</b>–<b>1d</b> with Rh­(I), Ir­(III), and Ni(0) precatalysts in THF at 20 °C resulted in an array of products, including aminoborane RR′NBHMe, cyclic diborazane [RR′N–BHMe]₂, and borazine [RN–BMe]₃ based on analysis by in situ ¹¹B NMR spectroscopy, with peak assignments further supported by density functional theory (DFT) calculations. Significantly, very rapid, metal-free hydrogen transfer between <b>1a</b> and the monomeric aminoborane, <i>i</i>Pr₂NBH₂, to yield <i>i</i>Pr₂NH·BH₃ (together with dehydrogenation products derived from <b>1a</b>) was complete within only 10 min at 20 °C in THF, substantially faster than for the N-substituted analogue MeNH₂·BH₃. DFT calculations revealed that the hydrogen transfer proceeded via a concerted mechanism through a cyclic six-membered transition state analogous to that previously reported for the reaction of the <i>N</i>-dimethyl species Me₂NH·BH₃ and <i>i</i>Pr₂NBH₂. However, as a result of the presence of an electron donating methyl substituent on boron rather than on nitrogen, the process was more thermodynamically favorable and the activation energy barrier was reduced