No abstract

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract infection among infants and young children, resulting in annual epidemics worldwide. INFORM-RSV is a multi-year clinical study designed to describe the global molecular epidemiology of RSV in children under five years of age by monitoring temporal and geographical evolution of current circulating RSV strains, F protein antigenic sites, and their relationships with clinical features of RSV disease. During the pilot season (2017–2018), 410 RSV G-F gene sequences were obtained from 476 RSV-positive nasal samples collected from 8 countries (United Kingdom, Spain, the Netherlands, Finland, Japan, Brazil, South Africa, and Australia). RSV B (all BA9 genotype) predominated over RSV A (all ON1 genotype) globally (69.0% vs. 31.0%) and in all countries except South Africa. Geographic clustering patterns highlighted wide transmission and continued evolution with viral spread. Most RSV were from infants <1 year of age (81.2%), males (56.3%), and patients hospitalized >24 hours (70.5%) with no differences in subtype distribution. Compared to 2013 reference sequences, variations at F protein antigenic sites were observed for both RSV A and B strains with high frequency polymorphisms at antigenic site Ø (I206M/Q209R) and site V (L172Q/S173L/K191R) in RSV B strains. The INFORM-RSV 2017–2018 pilot season establishes an important molecular baseline of RSV strain distribution and sequence variability with which to track the emergence of new strains and provide an early warning system of neutralization escape variants that may impact transmission or the effectiveness of vaccines and mAbs under development.

1 The effects of several adenosine analogues and antagonists on guinea-pig isolated trachea have been examined. 2 5'-N-ethylcarboxamidoadenosine (NECA), 5'-N-methylcarboxamidoadenosine (MECA) and adenosine (in the presence and absence of dipyridamole) elicited concentration-dependent tracheal relaxation.3 The R(-)-and S( +)-enantiomers of N642-phenylisopropyl)adenosine (R-PIA and S-PIA respectively), N6-cyclohexyladenosine (CHA) and 2-chloroadenosine (CADO) caused contractions at low concentrations (0.05-2.0 yM), whereas at higher concentrations, relaxation resulted. 4 For tracheal relaxation, the adenosine analogues exhibited the following rank order of potency: NECA > CADO > R-PIA = MECA > S-PIA > adenosine. The rank order of potency for inducing contractions was R-PIA > CHA > CADO > S-PIA. These data suggest that relaxation is mediated by adenosine A2-receptors, whereas contraction is the result of activation of A -receptors. 5 8-Phenyltheophylline (8-PT), aminophylline, the triazoloquinazoline CGS 15943A and NPC205 (1,3-di-n-propyl-8-(4-hydroxyphenyl)xanthine) each inhibited the R-PIA-induced contractile response, whereas enprofylline was without effect. NPC205, aminophylline and 8-PT were competitive antagonists, but CGS15943A was non-competitive. 6 That the most potent antagonist was the A1-selective agent, NPC205 (pA2 = 7.80), further suggests that the contraction is mediated by A1-receptors. Moreover, NPC205 was 13 times more potent as an antagonist of R-PIA-induced contractions (A1) than of NECA-induced relaxations (A2).7 The antagonists were also found to relax the trachea by an unknown mechanism. That enprofylline did not antagonize the R-PIA-induced contractions, but was 3-4 times more potent a tracheal relaxant than aminophylline, further suggests that a direct effect on airway smooth muscle, rather than antagonism of endogenous adenosine, is more relevant to the bronchodilator effect of alkylxanthines in the treatment of asthma.

1Cellular dielectric spectroscopy (CDS) is an emerging technology capable of detecting a range of whole-cell responses in a label-free manner. A new CDS-based instrument, CellKey, has been developed that is optimized for G-protein coupled receptor (GPCR) detection and has automated liquid handling in microplate format, thereby making CDS accessible to lead generation/optimization drug discovery. In addition to having sufficient throughput, new assay technologies must pass rigorous standards for assay development, signal window, dynamic range, and reproducibility to effectively support drug discovery SAR studies. Here, the authors evaluated CellKey with 3 different G i -coupled GPCRs for suitability in supporting SAR studies. Optimized assay conditions compatible with the precision, reproducibility, and throughput required for routine screening were quickly achieved for each target. Across a 1000-fold range in compound potencies, CellKey results correlated with agonist and antagonist data obtained using classical methods ([ 35 S]GTPγS binding and cAMP production). For partial agonists, relative efficacy measurements also correlated with GTPγS data. CellKey detection of positive allosteric modulators appeared superior to GTPγS methodology. Agonist and antagonist activity could be accurately quantified under conditions of low receptor expression. CellKey is a new technology platform that uses label-free detection in a homogeneous assay that is unaffected by color quenching and is easily integrated into existing microtiter-based compound testing and data analysis procedures for drug discovery. (Journal of Biomolecular Screening 2007:312-319)