Structural Studies of West Nile Virus in Complex with Neutralizing Antibodies.

West Nile virus (WNV) is a positive strand RNA virus in the family Flaviviridae, which includes members such as dengue, Japanese encephalitis, tick-borne encephalitis, yellow fever and Hepatitis C. As with other members of the genus, it is arthropod transmitted and has recently established itself as an endemic virus in the United States. Although most infections are asymptomatic, clinical manifestations of WNV include encephalitis and death. We have been interested in investigating the nature of the immune response with particular emphasis on the role of antibodies in reducing the level of infection. We have used a combination of techniques, but primarily structure, as a tool to probe the nature of antibody-mediated virus neutralization. Our results suggest that neutralization of virus particles is more complex than originally envisioned, with multiple mechanisms utilized. Using a combination of X-ray crystallography and cryo-electron microscopy, several virus-antibody complexes have been determined at pseudo-atomic resolution. These studies suggest the following: 1) flavivirus particles exhibit dynamic motions or breathing that transiently expose cryptic epitopes; 2) although there are 180 potential binding sites for each monoclonal antibody the quasi-equivalent nature of the virion usually permits only a subset of sites to be utilized; 3) the availability of these sites, the epitope itself, and the avidity of antibody directly influence the mechanism of neutralization; and 4) particles thought to be incapable of infecting cells, so-called immature viruses, may play a critical role in immune surveillance and reactivity. The structure of the flavivirus virion and complexes of monoclonal antibodies will be presented along with data to support mechanisms antibody-mediated flavivirus neutralizatio

The Low Prevalence of Overweight and Obesity in Czech Breastfed Infants and Young Children: An Anthropological Survey

The aim of this study is to evaluate the prevalence of overweight and obesity in a sample of children who were exclusively or predominantly breastfed for at least 6 months compared to Czech references that were constructed based on a representative sample of children, regardless of their mode of feeding. Between 2008 and 2011, a longitudinal study on the growth of breastfed infants was carried out in the Czech Republic. Forty-three GP pediatricians addressed parents at 18-month preventive examinations and collected data on the families’ socio-economic conditions and the infants’ feeding conditions. The children were measured (length, weight, and head circumference), and anthropometric measurements from 10 previous preventive examinations were obtained from the health records. Out of the collected 1775 questionnaires, 960 children were selected according to the criteria of the WHO Multicentre Growth Reference Study. For the purpose of this study, 799 children who were exclusively or predominantly breastfed for at least 6 months were selected. We found that the proportions of children who were classified as overweight (>90th percentile) or obese (>97th percentile) at 6, 12, and 18-month examinations were far below the proportions of the Czech references. An update of the Czech references and growth charts is highly recommended by GP pediatricians for the valid assessment of growth and nutritional status, including a screening of overweight and obesity in primary preventive health care

Structures of immature flavivirus particles

Structures of prM-containing dengue and yellow fever virus particles were determined to 16 and 25 Å resolution, respectively, by cryoelectron microscopy and image reconstruction techniques. The closely similar structures show 60 icosahedrally organized trimeric spikes on the particle surface. Each spike consists of three prM:E heterodimers, where E is an envelope glycoprotein and prM is the precursor to the membrane protein M. The pre-peptide components of the prM proteins in each spike cover the fusion peptides at the distal ends of the E glycoproteins in a manner similar to the organization of the glycoproteins in the alphavirus spikes. Each heterodimer is associated with an E and a prM transmembrane density. These transmembrane densities represent either an EE or prMprM antiparallel coiled coil by which each protein spans the membrane twice, leaving the C-terminus of each protein on the exterior of the viral membrane, consistent with the predicted membrane-spanning domains of the unprocessed polyprotein

Teprotumumab Efficacy, Safety, and Durability in Longer-Duration Thyroid Eye Disease and Re-treatment: OPTIC-X Study

PURPOSETo evaluate teprotumumab safety/efficacy in patients with thyroid eye disease (TED) who were nonresponsive or who experienced a disease flare. DESIGNThe Treatment of Graves' Orbitopathy to Reduce Proptosis with Teprotumumab Infusions in an Open-Label Clinical Extension Study (OPTIC-X) is a teprotumumab treatment and re-treatment trial following the placebo-controlled teprotumumab Phase 3 Treatment of Graves' Orbitopathy (Thyroid Eye Disease) to Reduce Proptosis with Teprotumumab Infusions in a Randomized, Placebo-Controlled, Clinical Study (OPTIC) trial. PARTICIPANTSPatients who previously received placebo (n = 37) or teprotumumab (n = 14) in OPTIC. METHODSOPTIC nonresponders or those who flared (≥2-mm increase in proptosis, ≥2-point increase in clinical activity score [CAS], or both) during follow-up were treated for the first time (previous placebo patients) or re-treated with teprotumumab in OPTIC-X with 8 infusions over 24 weeks. MAIN OUTCOME MEASURESProptosis response and safety. Secondary outcomes included proptosis, CAS, subjective diplopia, and quality-of-life. RESULTSThirty-three of 37 placebo-treated OPTIC patients (89.2%) became proptosis responders (mean ± standard deviation, -3.5 ± 1.7 mm) when treated with teprotumumab in OPTIC-X. The responses were equivalent to the OPTIC study. In these responders, proptosis, CAS of 0 or 1, and diplopia responses were maintained in 29 of 32 patients (90.6%), 20 of 21 patients (95.2%), and 12 of 14 patients (85.7%), respectively, at follow-up week 48. The median TED duration was 12.9 months versus 6.3 months in those treated with teprotumumab in the OPTIC study. Of the 5 OPTIC teprotumumab nonresponders re-treated in OPTIC-X, 2 responded, 1 showed a proptosis reduction of 1.5 mm from OPTIC baseline, and 2 discontinued treatment early. Of the OPTIC teprotumumab responders who experienced flare, 5 of 8 patients (62.5%) responded when re-treated (mean proptosis reduction, 1.9 ± 1.2 mm from OPTIC-X baseline and 3.3 ± 0.7 mm from OPTIC baseline). Compared with published double-masked trials and their integrated follow-up, no new safety signals were identified. Mild hearing impairment was reported; 4 events occurred during first course of treatment, and 2 events reoccurred after re-treatment. CONCLUSIONSPatients with TED of longer disease duration responded similarly to those treated earlier in the disease course. Patients with an insufficient initial response or flare may benefit from additional teprotumumab therapy. No new safety risk was identified; however additional postmarketing pharmacovigilance is ongoing