A risk‐based decision‐making framework for blood safety: what's the case for Zika?

Risk‐based decision‐making (RBDM) is a systematic approach to decision‐making that strives to minimize risk, optimize outcomes and prioritize resources for maximum good. Such is achieved by weighing all the factors that influence policy for a given threat, drawing on the best available scientific data, engaging key stakeholders, while still considering the complex interplay of ethics, social values, politics, economics, culture and historical precedent that argue for or against intervention. In the context of blood transfusion safety, attention to RBDM stems from a growing awareness that the current paradigm of ‘safety at any cost’ is unsustainable and unbalanced. By contrast, RBDM emphasizes proportionality and encourages review of decisions as new data emerge. Zika virus (ZIKV), a formerly obscure mosquito‐borne flavivirus, emerged rapidly in 2015, spurring an international public health emergency. The mandatory adoption of laboratory‐based blood donor screening for ZIKV in the United States (US) in 2016 remains contentious. Clinical cases of transfusion‐transmitted ZIKV infection have never been reported, and four years after the emergence of ZIKV in the Americas, the pandemic has waned, suggesting that the donor screening for ZIKV is high cost yet of questionable benefit. The US response to ZIKV offers an illustrative case study of the challenges surrounding intervention to protect the blood supply from emerging pathogens, and how an RBDM framework might help to guide policy. However, careful assessment (i.e. RBDM) alone does not guarantee a desirable outcome. Rather, risk‐tolerance in a given setting should not be understated.     

From virus to vaccine: recombinant mammalian cell lines as substrates for the production of herpes simplex virus vaccines

The use of mammalian cells as substrates for the production of various vaccines is a time-honored procedure. With the advent of recombinant DNA technology, various investigators soon realized that these techniques could be applied to mammalian cells to convert them to reliable, safe producers of a variety of vaccines. While none of these types of recombinant vaccines have, as yet, been widely utilized, many individuals believe that these technologies are the wave of the future in vaccine production. In this paper our work on the use of mammalian cells for the development of subunit vaccines for the prevention of infection by herpes simplex virus (HSV) types 1 and 2 is reviewed. A surface glycoprotein of these viruses, gD, was chosen as a likely candidate for a subunit vaccine based upon its primary sequence conservation between the two viral types as well as upon data suggesting that antibodies against this glycoprotein were highly efficient at neutralizing virus infectivity. Stable mammalian cell lines were constructed that expressed secreted forms of this protein, and the protein could be purified from cell-conditioned supernatants to near-homogeneity. Vaccination of mice with this glycoprotein was found to protect them from a lethal intraperitoneal infection by either the type 1 or type 2 forms of this virus. In a more realistic study, guinea pigs vaccinated with either the type 1 or type 2 form of gD were found to be protected from a genital form of HSV 2 infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

CD4+ and CD8+ T‐cell immunity to Dengue – lessons for the study of Zika virus

Dengue virus (DENV) and Zika virus (ZIKV) are rapidly emerging mosquito‐borne flaviviruses that represent a public health concern. Understanding host protective immunity to these viruses is critical for the design of optimal vaccines. Over a decade of research has highlighted a significant contribution of the T‐cell response to both protection and/or disease enhancement during DENV infection, the latter being mainly associated with sub‐optimal cross‐reactive T‐cell responses during secondary infections. Phase IIb/III clinical trials of the first licensed tetravalent dengue vaccine highlight increased vaccine efficacy in dengue‐immune as opposed to dengue‐naive vaccinees, suggesting a possible immunoprotective role of pre‐existing DENV‐specific T cells that are boosted upon vaccination. No vaccine is available for ZIKV and little is known about the T‐cell response to this virus. ZIKV and DENV are closely related viruses with a sequence identity ranging from 44% and 56% for the structural proteins capsid and envelope to 68% for the more conserved non‐structural proteins NS3/NS5, which represent the main targets of the CD4⁺ and CD8⁺ T‐cell response to DENV, respectively. In this review we discuss our current knowledge of T‐cell immunity to DENV and what it can teach us for the study of ZIKV. The extent of T‐cell cross‐reactivity towards ZIKV of pre‐existing DENV‐specific memory T cells and its potential impact on protective immunity and/or immunopathology will also be discussed.     

Computer analysis of antigenic domains and RGD-like sequences (RGWG) in the E glycoprotein of flaviviruses: An approach to vaccine development

Antigenic domains and RGD-like sequences in the E glycoprotein of the flaviviruses Japanese encephalitis virus, yellow fever virus, West Nile virus, dengue type 4 virus, and tick-borne encephalitis virus were analyzed by computer programs that provide information on the physical properties of the polypeptides. The use of computer programs for the development of vaccines based on the synthesis of antigenic peptides is discussed. Synthetic viral peptides are proposed to be used for topical application so as to interfere with the virus-cell interaction. Viral peptides with antigenic epitopes to protect against dengue virus infection without enhancing pathogenesis may also be developed on the basis of the computer analysis.     

An attenuated West Nile prototype virus is highly immunogenic and protects against the deadly NY99 strain: a candidate for live WN vaccine development

In a short time, West Nile virus has developed into a nationwide health and veterinary problem. The high virulence of the circulating virus and related lineage 1 WN strains hinders development of an attenuated live vaccine. We describe an attenuated WN isolate, WN1415, which is a molecularly cloned descendant of the WN prototype B956 strain. The parent virus belongs to lineage 2, members of which have not been associated with epidemic or epizootic outbreaks. A set of non-conservative mutations, mostly in non-structural protein genes, distinguishes the WN1415 isolate from the parent B956 prototype strain. Immunization with WN1415 (55-550,000 pfu) established a potent immunity, which protected the majority of mice against lethal challenge with WN NY99. The attenuated nature of the isolate and its excellent growth characteristics combined with the availability of a highly stable infectious clone make the isolate an attractive candidate for live WN vaccine development.     

Signaling pathways involved in the T‐cell‐mediated immunity against Epstein‐Barr virus: Lessons from genetic diseases

Primary immunodeficiencies (PIDs) provide researchers with unique models to understand in vivo immune responses in general and immunity to infections in particular. In humans, impaired immune control of Epstein‐Barr virus (EBV) infection is associated with the occurrence of several different immunopathologic conditions; these include non‐malignant and malignant B‐cell lymphoproliferative disorders, hemophagocytic lymphohistiocytosis (HLH), a severe inflammatory condition, and a chronic acute EBV infection of T cells. Studies of PIDs associated with a predisposition to develop severe, chronic EBV infections have led to the identification of key components of immunity to EBV – notably the central role of T‐cell expansion and its regulation in the pathophysiology of EBV‐associated diseases. On one hand, the defective expansion of EBV‐specific CD8 T cells results from mutations in genes involved in T‐cell activation (such as RASGRP1, MAGT1, and ITK), DNA metabolism (CTPS1) or co‐stimulatory pathways (CD70, CD27, and TNFSFR9 (also known as CD137/4‐1BB)) leads to impaired elimination of proliferating EBV‐infected B cells and the occurrence of lymphoma. On the other hand, protracted T‐cell expansion and activation after the defective killing of EBV‐infected B cells is caused by genetic defects in the components of the lytic granule exocytosis pathway or in the small adapter protein SH2D1A (also known as SAP), a key activator of T‐ and NK cell‐cytotoxicity. In this setting, the persistence of EBV‐infected cells results in HLH, a condition characterized by unleashed T‐cell and macrophage activation. Moreover, genetic defects causing selective vulnerability to EBV infection have highlighted the role of co‐receptor molecules (CD27, CD137, and SLAM‐R) selectively involved in immune responses against infected B cells via specific T‐B cell interactions.     

An eigenvalue approach for the automatic scaling of unknowns in model‐based reconstructions: Application to real‐time phase‐contrast flow MRI

The purpose of this work is to develop an automatic method for the scaling of unknowns in model‐based nonlinear inverse reconstructions and to evaluate its application to real‐time phase‐contrast (RT‐PC) flow magnetic resonance imaging (MRI). Model‐based MRI reconstructions of parametric maps which describe a physical or physiological function require the solution of a nonlinear inverse problem, because the list of unknowns in the extended MRI signal equation comprises multiple functional parameters and all coil sensitivity profiles. Iterative solutions therefore rely on an appropriate scaling of unknowns to numerically balance partial derivatives and regularization terms. The scaling of unknowns emerges as a self‐adjoint and positive‐definite matrix which is expressible by its maximal eigenvalue and solved by power iterations. The proposed method is applied to RT‐PC flow MRI based on highly undersampled acquisitions. Experimental validations include numerical phantoms providing ground truth and a wide range of human studies in the ascending aorta, carotid arteries, deep veins during muscular exercise and cerebrospinal fluid during deep respiration. For RT‐PC flow MRI, model‐based reconstructions with automatic scaling not only offer velocity maps with high spatiotemporal acuity and much reduced phase noise, but also ensure fast convergence as well as accurate and precise velocities for all conditions tested, i.e. for different velocity ranges, vessel sizes and the simultaneous presence of signals with velocity aliasing. In summary, the proposed automatic scaling of unknowns in model‐based MRI reconstructions yields quantitatively reliable velocities for RT‐PC flow MRI in various experimental scenarios.     

Detection of the Epstein-Barr virus genome in cervical neoplasia is closely related to the degree of infiltrating lymphoid cells: A polymerase chain reaction and in situ hybridization approach

To cast light on the significance of Epstein-Barr virus (EBV) infection In cervical tumorigenesie, 44 cervical lntraepithellal neoplasia (CIN) types I/II, and 70 CIN III lesions, 60 lnvasive squamous cell carcinomas (ISCC), and 20 normal cervical samples were Investigated by polymerase chain reaction (PCR) and RNA in situ hybridization (RISH) assays. The EBV genome was detected by PCR using primers targetlng the IR region in three (6.8%0) of the CIN I/II, 15 (21.4%) of the CIN III and 13 (21.7%) of the ISCC lesions, while using an EBER oligonucieotide probe RISH revealed positive signals in Infiltrating lymphocytes located In the cervical stroma, but not in dysplastic or tumor cells. There was a significant correlation between the presence of EBV DNA and the degree of lymphoid cell infiltratlon ( P =0.0223). In contrast, none of the normal cervical samples that were without inflammation demonstrated any EBV infection. Thus, the results indicated that a positive result for EBV on PCR may be simply dependent on the amount of lymphocytes in cervical stroma, suggesting that this virus does not play a major role In the etiology of cervical neoplasia.     

An anatomic‐based approach to the iatrogenic spinal accessory nerve injury in the posterior cervical triangle: How to avoid and treat it

Iatrogenic injury of the spinal accessory nerve (SAN) is a significant reducible risk with any invasive procedure involving the posterior cervical triangle. Most commonly associated with cervical lymph node biopsy, it affects 3–6% of patients and serves as a major cause of avoidable medical malpractice litigation. Medical malpractice cases not only affect the primary surgeon but also may include the repairing surgeon through a shift of blame. For this reason, we discuss the strategies all clinicians may utilize in approaching iatrogenic SAN injuries. By taking basic precautionary measures based on simple application of anatomy in the management of these patients, clinicians may protect themselves from needless malpractice litigation. A thorough knowledge of the anatomy and application in preventative strategies may provide guidance for clinicians in reducing the incidence of iatrogenic injuries, providing effective postinjury management, and ensuring the salvaging surgeon is not at fault if litigation is pursued. Clin. Anat. 28:761–766, 2015. © 2015 Wiley Periodicals, Inc.     

Proteinase K is an activator for the male‐dependent spermiogenesis pathway in Caenorhabditis elegans: Its application to pharmacological dissection of spermiogenesis

Caenorhabditis elegans spermiogenesis involves spermatid activation into spermatozoa. Activation occurs through either SPE‐8 class‐dependent or class‐independent pathways. Pronase (Pron) activates the SPE‐8 class‐dependent pathway, whereas no in vitro tools are available to stimulate the SPE‐8 class‐independent pathway. Thus, whether there is a functional relationship between these two pathways is currently unclear. In this study, we found that proteinase K (ProK) can activate the SPE‐8 class‐independent pathway. In vitro spermiogenesis assays using Pron and ProK suggested that SPE‐8 class proteins act in the hermaphrodite‐ and male‐dependent spermiogenesis pathways and that some spermatid proteins presumably working downstream of spermiogenesis pathways, including MAP kinases, are preferentially involved in the SPE‐8 class‐dependent pathway. We screened a library of chemicals, and a compound that we named DDI‐1 inhibited both Pron‐ and ProK‐induced spermiogenesis. To our surprise, several DDI‐1 analogues that are structurally similar to DDI‐1 blocked Pron, but not ProK, induced spermiogenesis. Although the mechanism by which DDI‐1 blocks spermiogenesis is yet unknown, we have begun to address this issue by selecting two DDI‐1‐resistant mutants. Collectively, our data support a model in which C. elegans male and hermaphrodite spermiogenesis each has its own distinct, parallel pathway.     

Titration of hepatitis B virus infectivity in the sera of pre‐acute and late acute phases of HBV infection: Transmission experiments to chimeric mice with human liver repopulated hepatocytes

Studies of hepatitis B virus (HBV) infection in non‐human primates such as chimpanzees are no longer possible due to ethical considerations and the endangered status of chimpanzees since April 2007 in Japan. A human hepatocyte transplanted chimeric mouse was used to characterize HBV infectivity in serial stages of acute infection. Chimeric mice were inoculated intravenously with serum samples obtained from an experimentally infected chimpanzee with HBV. Sera from the pre‐acute phases (i.e., rump‐up viremia prior to anti‐HBc) and late acute phases (i.e., declining phase of HBsAg and anti‐HBcAb positive) were collected from the chimpanzees 57 and 244 days after inoculation. These sera contained 2.6 × 10⁶ and 2.8 × 10⁶ copies/ml of HBV DNA, respectively. Three chimeric mice inoculated intravenously with 100 µl of pre‐acute serum (equivalent to 10⁰ copy of HBV DNA) developed an HBV infection. The three chimeric mice that received 100 µl of pre‐acute serum (equivalent to 10¹ copies of HBV DNA), developed high levels of serum HBV DNA. None of the three chimeric mice inoculated with 100 µl of 1:10⁴ dilution (equivalent to 10¹ copies of HBV DNA) of late‐acute serum was infected, while only one of three chimeric mice inoculated with 100 µl of 1:10³ dilution (equivalent to 10² copies of HBV DNA) of late‐acute serum developed an HBV infection. Based on these results, chimeric mice can be used as animal models for the study of HBV infectivity, pathogenesis and control. The results show that pre‐acute phase HBV serum is about 100‐times more infectious than late acute phase serum. J. Med. Virol. 80:2064–2068, 2008. © 2008 Wiley‐Liss, Inc.