91 research outputs found
Emerg Infect Dis
No full textDuring February 2018-January 2019, we conducted large-scale surveillance for the presence and prevalence of tick-borne encephalitis virus (TBEV) and louping ill virus (LIV) in sentinel animals and ticks in the United Kingdom. Serum was collected from 1,309 deer culled across England and Scotland. Overall, 4% of samples were ELISA-positive for the TBEV serocomplex. A focus in the Thetford Forest area had the highest proportion (47.7%) of seropositive samples. Ticks collected from culled deer within seropositive regions were tested for viral RNA; 5 of 2,041 ticks tested positive by LIV/TBEV real-time reverse transcription PCR, all from within the Thetford Forest area. From 1 tick, we identified a full-length genomic sequence of TBEV. Thus, using deer as sentinels revealed a potential TBEV focus in the United Kingdom. This detection of TBEV genomic sequence in UK ticks has important public health implications, especially for undiagnosed encephalitis
Use and reliability of multiplex bead-based assays (Luminex) at Containment Level 4.
No full textIn the UK, research on hazard group 4 (HG4) pathogens requires specialised Containment Level 4 (CL4) facilities. These differ from Biosafety Level 4 (BSL4) conditions in that work is conducted in class III microbiological safety cabinets for primary containment instead of using positive pressure suits. This presents unique challenges associated with the physical restrictions of working in a limited space, and prohibits the use of many techniques and specialist equipment. In consequence, detailed studies on the biology of HG4 pathogens and in particular their immunological relationships with the host are understudied in the UK; for example, the majority of immunological assays with which the immune system is interrogated require specialist equipment that is unsuitable for CL4. Multiplexing to simultaneously measure multiple analytes is increasingly being used in immunological studies. This assay is attractive for CL4 work because it reduces the time spent in the laboratory whilst maximising the use of valuable sample volume. The Luminex microsphere approach allows for the determination of many cytokines and chemokines, however, the detection system uses fixed aligned lasers and integrated computer systems which are unsuitable for use at CL4. Therefore, we have developed an approach in which the Luminex assay is conducted within the CL4 laboratory and a formalin-fixation stage is introduced to allow for analysis to be undertaken outside of containment. Quality control preparations allow the assay characteristics to be monitored and analysis of assay performance to be evaluated. Our data demonstrate that Luminex is an applicable tool for use at CL4 and that assays can be run reliably to generate reproducible standardised data across different plates and individual experiments.</p
Tissue histology of A129 mice, 4 days after challenge with CCHFv.
No full text<p>A129 mice were challenged with double the minimum lethal dose of CCHFv, 14 days after booster vaccination with MVA 1974 (A–B) or MVA-GP (C–D). Four days after challenge, sections of spleen (A, C) and liver (B, D) were fixed, HE stained, and examined for pathology. More severe pathology was found in mice that received MVA 1974, compared to those that received MVA-GP. (A) Marked lymphocyte loss with prominent apoptotic bodies, and infiltration by macrophages. (B) Marked, multifocally extensive hepatocyte necrosis (arrows). (C) A single infiltration of macrophages in the white pulp (asterisk) (scored minimal). (D) Scattered, multifocal areas of hepatocellular necrosis with a mixed inflammatory cell infiltrate (arrows) (scored moderate).</p
Immunohistochemistry of tissues from A129 mice, 4 days after challenge with CCHFv.
No full text<p>A129 mice were challenged with double the minimum lethal dose of CCHFv, 14 days after booster vaccination with MVA 1974 (A–C) or MVA-GP (D–E). Four days after challenge, sections of spleen (A, D) and liver (B–C, E) were fixed, immunohistochemically stained with CCHFv-specific antibody, and examined microscopically. Tissues in panels A, B, D and E were from the same individuals as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091516#pone-0091516-g007" target="_blank">Figures 7A, 7B, 7C and 7D</a>, respectively. A diffuse staining pattern of viral proteins was found in tissues from animals that received the MVA 1974 negative control. However, in MVA-GP vaccinated animals, the only staining found was of a minimal degree, in liver from one individual. (A) A few, scattered cells with cytoplasmic staining within the parenchyma. (B) Frequent, diffuse, positively stained hepatocytes. (C) Scattered, small, elongated cells consistent with Kupffer cells, with cytoplasmic staining. (D) Normal parenchyma. (E) A few, positively stained cells within an inflammatory cell focus.</p
The Development of a Novel Diagnostic Assay That Utilizes a Pseudotyped Vesicular Stomatitis Virus for the Detection of Neutralizing Activity against Crimean-Congo Hemorrhagic Fever Virus
No full textSpecificity, cross-reactivity, and function of antibodies elicited by Zika virus infection
No full textZika virus (ZIKV), a mosquito-borne flavivirus with homology to Dengue virus (DENV), has become a public health emergency. By characterizing memory lymphocytes from ZIKV-infected patients, we dissected ZIKV-specific and DENV-cross-reactive immune responses. Antibodies to nonstructural protein 1 (NS1) were largely ZIKV-specific and were used to develop a serological diagnostic tool. In contrast, antibodies against E protein domain I/II (EDI/II) were cross-reactive and, although poorly neutralizing, potently enhanced ZIKV and DENV infection in vitro and lethally enhanced DENV disease in mice. Memory T cells against NS1 or E proteins were poorly cross-reactive, even in donors preexposed to DENV. The most potent neutralizing antibodies were ZIKV-specific and targeted EDIII or quaternary epitopes on infectious virus. An EDIII-specific antibody protected mice from lethal ZIKV infection, illustrating the potential for antibody-based therapy
Expression and characterization of codon-optimized Crimean-Congo hemorrhagic fever virus Gn glycoprotein in insect cells
No full textInterferon-beta (IFNβ) Inhibits Infection Of A Lung Epithelial Cell Line With Novel Variant H1N1 (‘swine Flu’) Influenza Virus
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