Search

Background: CpG oligodeoxynucleotides (ODNs), resembling bacterial DNA, are currently tested in clinical trials as vaccine adjuvants. They have the nuclease-resistant phosphorothioate bond; the immune responses elicited differ according to the CpG ODN sequence and vaccination method. To develop a CpG ODN that can induce plasmacytoid dendritic cell (pDC)-mediated TH1 immunity through the mucosa, we constructed phosphodiester G9.1 comprising one palindromic CpG motif with unique polyguanosine-runs that allows degradation similar to naturally occurring bacterial DNA. Methods: TH1 and TH2 immunity activation was evaluated by cytokine production pattern and T-bet/GATA-3 ratio in human peripheral blood mononuclear cells and mouse bone marrow cells. Adjuvanticity was evaluated in mice administered G9.1 with diphtheria toxoid (DT) through nasal vaccination. Results: G9.1 exhibited stronger IFN-α-inducing activity than A-class CpG ODN2216 and increased T-bet/GATA-3 ratio by enhancing T-bet expression. Nasally administered G9.1 plus DT induced DT-specific mucosal IgA and serum IgG, but not IgE, responses with antitoxin activity in C57BL/6 and BALB/c mice, possibly due to IFN/BAFF production. Induction of TH1, but not TH2, -type Abs depended completely on pDCs, the first in vivo demonstration by CpG ODNs. Conclusions: G9.1 is a promising mucosal adjuvant for induction of pDC-mediated TH1 immunity. [ABSTRACT FROM AUTHOR]

Spiders synthesize several kinds of silk fibers. In the primary structure of spider silk, one of the major ampullate (dragline, frame) silks, spidroin 1, and flagelliform silk (core fibers of adhesive spiral), there are common repeated X-Gly-Gly (X = Ala, Leu, Pro, Tyr, Glu, and Arg) sequences, which are considered to be related to the elastic character of these fibers. In this paper, two dimensional spin diffusion solid-state NMR under off magic angle spinning (OMAS), 13C chemical shift contour plots, and Rotational Echo DOuble Resonance (REDOR) were applied to determine the torsion angles of one Ala and two kinds of Gly residues in the Ala-Gly-Gly sequence of 13C=O isotope-labeled (Ala-Gly-Gly)10. The torsion angles were determined to be (φ, ψ) = (-90°, 150° ) within an experimental error of ±10° for each residue. This conformation is characterized as 31 helix which is in agreement with the structure proposed from the X-ray powder diffraction pattern of poly(Ala-Gly-Gly). The 31 helix of (Ala-Gly-Gly)10 does not change by formic acid treatment although (Ala-Gly)15 easily changes from the silk I conformation (the structure of Bombyx mori silk fibroin before spinning in the solid state) to silk II conformation (the structure of the silk fiber after spinning) by such treatment. Thus, the 31 helix conformation of (Ala-Gly-Gly)10 is considered very stable. Furthermore, the torsion angles of the 16th Leu residue of (Leu-Gly-Gly)10 were also determined as (φ, ψ) = (-90°, 150° ) and this peptide is also considered to take 31 helix conformation. [ABSTRACT FROM AUTHOR]