Evaluation of the Kinetic Change of the Immunogenicity of Dengue-2 DNA Vaccine in Mice Administered by Different Administration Routes

A plasmid DNA vaccine is able to induce both humoral and cellular immune responses;however, the kinetic change of the Th1/Th2 response, antibody avidity, cytokine secretion, and neutralization activity after different priming and boosting strategies have not been evaluated. A plasmid DNA, designated pCBD2 and previously shown to efficiently induce an immune response very similar to that by a wild type virus, was evaluated kinetically in this study. Our results suggest that a DNA vaccine delivered by the gene gun (gg) route produced higher and longer DENV-2-specific antibody titers than those induced through the intramuscular (im) route. Although the gg group induced a Th2 response and im delivery induced a Th1 response, priming by gg delivery, followed by a boosting by im delivery, did not shift the immune response from a Th2 to Th1 response. Furthermore, the antibody avidity (AI) measured by ELISA demonstrated a gradual increase of AI from low (AI range from 6.8% - 9.6%) on day 42 to high (AI value > 30) on day 119 in all but the gene-gun immunization group, in which an AI value of 23 was observed. Although there was lower avidity in the gg group, the mice sera from all three groups of mice demonstrated significant neutralization activity. This is the first report about the kinetics of immunogenicity of a DNA vaccine through different administration strategies, which suggests that gene gun delivery of a DNA vaccine can induce an immune response containing both neutralizing and nonneutralizing antibodies at high titers important for neutralization.

The Ortholog of LYVE-1 Is Required for Thoracic Duct Formation in Zebrafish

LYVE-1 (also termed CRSBP-1), a 120-kDa disulfide-linked dimeric type I membrane glycoprotein, is a specific marker for lymphatic endothelial cells (LECs) and exhibits multiple ligand (hyaluronic acid and growth factors/cytokines) binding activity in mammals. Recent studies indicate that LYVE-1/CRSBP-1 ligands (VEGF-A165, PDGF-BB, oligopeptides containing the cell-surface retention sequence (CRS) motifs of VEGF-A165 and PDGF-BB) induce opening of lymphatic intercellular junctions in vitro and in vivo. To determine the function of the ortholog of mammalian LYVE-1 in zebrafish, we cloned it (zLyve-1). The cloned cDNA (zLyve1) encodes a 328-amino-acid type I membrane glycoprotein. The protein and genomic structure evidence supports the notion that the cloned zLyve-1 is the ortholog of LYVE-1 in zebrafish. zLyve-1 expressed in cultured cells by transfection exhibits hyaluronic acid binding activity but lacks the growth factor binding activity seen in mammalian homologs. Knockdown of zLyve-1 levels by embryo microinjection with a specific antisense morpholino oligonucleotide (MO2) in wild-type and Tg(fli1:EGFP)-transgenic zebrafish causes defects in thoracic duct (TD) formation. Such zebrafish injected with MO2 also exhibit impaired TD flow (as determined by intramuscular injection of FITC-dextran). The phenotypes in these zebrafish injected with MO2 are reversed by co-injection with zLyve1cDNA. In situ hybridization reveals that zLyve-1 is expressed in the posterior cardinal vein (PCV). Expression of zLyve-1 at the highest level in the PCV occurs at 3 dpf which coincides with the time for TD formation in zebrafish development. These results suggest that zLyve-1 is required for TD formation. They also suggest that zLyve-1 is distinct from mammalian LYVE-1 in its role in lymphatic function.

Rapid separation of acetophenone and its monohydroxy isomers by capillary electrophoresis

This work describes the development of a capillary electrophoresis （CE） method for the simultaneous separation of acetophenone （AP）, 2-hydroxyacetophenone （2-HAP）, 3-hydroxyacetophenone （3-HAP） and 4-hydroxyacetophenone （4-HAP） in synthetic mixtures using 10 mmol/L of sodium tetraborate buffer （pH 9.5）. The aim of this work is to demonstrate the effectiveness of CE to separate AP and its monohydroxy isomers and to define how the separations are affected by buffers, buffer pH, sample matrices and separation voltage. This method was successfully used for the trace level separation and determination of 2-HAP, 3-HAP and 4-HAP in synthetic mixture and 4-HAP in spiked plasma samples.