Interleukin-13 Neutralization by Two Distinct Receptor Blocking Mechanisms Reduces Immunoglobulin E Responses and Lung Inflammation in Cynomolgus Monkeys

Interleukin (IL)-13 is a key cytokine driving allergic and asth-matic responses and contributes to airway inflammation in cynomolgus monkeys after segmental challenge with Ascaris suum antigen. IL-13 bioactivity is mediated by a heterodimeric receptor (IL-13R1/IL-4R) and can be inhibited in vitro by targeting IL-13 interaction with either chain. However, in cyto-kine systems, in vitro neutralization activity may not always predict inhibitory function in vivo. To address the efficacy of two different IL-13 neutralization mechanisms in a primate model of atopic disease, two humanized monoclonal antibod-ies to IL-13 were generated, with highly homologous proper-ties, differing in epitope recognition. Ab01 blocks IL-13 inter-action with IL-4R, and Ab02 blocks IL-13 interaction with IL-13R1. In a cynomolgus monkey model of IgE responses t

Rational design and synthesis of phospholipids for the two-dimensional crystallization of DNA gyrase, a key element in chromosome organization

International audienc

Identification of constrained peptides that bind to and preferentially inhibit the activity of the hepatitis C viral RNA-dependent RNA polymerase

AbstractA class of disulfide constrained peptides containing a core motif FPWG was identified from a screen of phage displayed library using the HCV RNA-dependent RNA polymerase (NS5B) as a bait. Surface plasmon resonance studies showed that three highly purified synthetic constrained peptides bound to immobilized NS5B with estimated Kd values ranging from 30 to 60 μM. In addition, these peptides inhibited the NS5B activity in vitro with IC50 ranging from 6 to 48 μM, whereas in contrast they had no inhibitory effect on the enzymatic activities of calf thymus polymerase α, human polymerase β, RSV polymerase, and HIV reverse transcriptase in vitro. Two peptides demonstrated conformation-dependent inhibition since their synthetic linear versions were not inhibitory in the NS5B assay. A constrained peptide with the minimum core motif FPWG retained selective inhibition of NS5B activity with an IC50 of 50 μM. Alanine scan analyses of a representative constrained peptide, FPWGNTW, indicated that residues F1 and W7 were critical for the inhibitory effect of this peptide, although residues P2 and N5 had some measurable inhibitory effect as well. Further analyses of the mechanism of inhibition indicated that these peptides inhibited the formation of preelongation complexes required for the elongation reaction. However, once the preelongation complex was formed, its activity was refractory to peptide inhibition. Furthermore, the constrained peptide FPWGNTW inhibited de novo initiated RNA synthesis by NS5B from a poly(rC) template. These data indicate that the peptides confer selective inhibition of NS5B activity by binding to the enzyme and perturbing an early step preceding the processive elongation step of RNA synthesis