HBECs (MucilAir) were purchased from Epithelix Sarl (Geneva, Switzerland), using the inserts containing epithelium of 14 donors. Each peptide grouping is presented in sequential order that shifts one amino acid at a time. The sequence of the highest-binding peptide per group, as well as the first peptide to demonstrate high binding in the 18-mer and 25-mer groups, are indicated with arrows. For panels (ACC), the paired cysteines that form the cystine noose are colored red (1C4) and green (2C3).(TIF) ppat.1006935.s001.tif (1.2M) GUID:?58E2EB1E-A2E1-41F8-A8FA-6292231C7BAA S2 Fig: RSV neutralization in immortalized cell cultures in the absence of complement. Antibody-mediated neutralization data, based upon a firefly luciferase assay using RSV CL57, performed in A549 cells in the absence of complement when incubated with CB017.5 IgG (green) or CB002.5 IgG (blue). Palivizumab IgG (red) is included as a positive control.(TIF) ppat.1006935.s002.tif (181K) GUID:?F07DDC4D-0CC3-4B50-96B5-866661ACE377 S3 Fig: Immunohistochemical staining of HBEC cultures. Microscopy images of HBEC cultures used in the neutralization assays. Cultures are immunohistochemically stained with alpha tubulin to indicate ciliated cells in red (A), Muc5AC to SAFit2 indicate mucin-containing goblet cells in green (B), or CD14 to indicate basal cells in blue (C).(TIF) ppat.1006935.s003.tif (1.6M) GUID:?3A1FFEB3-8597-45F1-BC06-08A4EF53548C S4 Fig: CB002.5 and CB017.5 bind with decreased affinity to a reduced and alkylated form of the G peptide. SPR response curves of Fab CB002.5 (A) and Fab CB017.5 (B) binding to a reduced and alkylated form of the subtype A RSV G peptide. The raw data are plotted in black, and the calculated best fit to a 1:1 binding model is plotted in red. The equilibrium dissociation constant (family. RSV virions have three proteins on the surface: the aforementioned F glycoprotein, the attachment glycoprotein (G), and the small MTF1 hydrophobic protein (SH) [7]. The F and G glycoproteins play an important role in SAFit2 mediating RSV infection and both are major targets of the humoral immune response [8C10]. RSV, and the related human metapneumovirus (hMPV), do not require the attachment protein for infection, indicating that the fusion protein alone is sufficient to mediate viral attachment and entry [11C14]. In contrast, viruses in the related family require the cognate attachment protein for infection, as it relays the signal of receptor binding to the F glycoprotein to initiate membrane fusion at the proper time and place [15C17]. However, despite no absolute requirement for the G glycoprotein among pneumoviruses [12, 13]. Therefore, the G protein could serve as an effective therapeutic target. RSV infection produces two forms of the G protein: the first is a full-length membrane-bound form that mediates viral attachment; the second is a secreted form (sG) that arises due to translation initiation at an AUG codon in the transmembrane domain [18C20]. Full-length RSV G is a type II membrane protein with 30C40 RSV cell culture model using human bronchial epithelial cells (HBECs) cultured at an air-liquid interface, colored as in A and B. (D) Cotton rat lung histopathology scores of each treatment group in the treatment arm of the study were evaluated six days after infection. Slides were scored blindly as described in the methods, with lower scores indicating reduced inflammation and SAFit2 pathology. The red line indicates the median of each group. (E) Infectious RSV titers in the lungs of cotton rats four days post-infection as determined by plaque assay. Different animal groups were injected prophylactically 24 hours prior to infection, or as a treatment one day after infection, as indicated. Animals used to determine viral titers were not included in the histopathological analysis. The red line indicates the mean viral titer. Gray dots indicate viral titers that were at the lower limit of detection. For panels (D) and (E): *p <.05, **p <.01, ns = not significant. To evaluate the clinical potential of G-directed antibodies that bind to the central conserved region,.