Biomedical subjects

Seong Ho Kang

Publications and source records attributed to Seong Ho Kang.

8 recordsLinked to original sources

PubMed2006

Differential segregation of protective immunity by encoded antigen in DNA vaccine against pseudorabies virus.

A murine model immunized with plasmid DNA vaccine expressing three glycoproteins pCIgB, pCIgC and pCIgD were used to examine the relative potency of major glycoproteins as well as the contribution of immunological parameters in providing protective immunity against the pseudorabies virus (PrV). Among the three glycoprotein-encoded plasmid DNA vaccines, pCIgB produced the strongest response of PrV-specific IgG in the sera. pCIgB and pCIgD also induced a contrast pattern of immunity that was biased to the Th1 and Th2 types, respectively. pCIgC showed the potent inducer of CD8+ T-cell-mediated CTL activity against PrV. In addition, a cocktail vaccination of all three glycoprotein-encoded plasmid DNA vaccines induced the production of both cytokine types, Th1 and Th2 with levels that were the same as that of each immunogen. With regard to protective efficacy, pCIgB induced the most effective protection against a virulent virus challenge and a cocktail vaccination appeared to offer complete protection against a 5 LD50 challenge, but not a 10 LD50 one. pCIgD induced protection that was same as pCIgB, but pCIgC offered no effective protection. These results show the relative potency of the three glycoprotein-encoded PrV DNA vaccines in inducing protective immunity against PrV infection. The results in this study support previous results showing the importance of Th1-type CD4+ T cells and their antibodies in conferring protection.

Animals↗

PubMed2006

Atypical mobilities of single native DNA molecules in microchip electrophoresis revealed by differential interference contrast microscopy.

A transmitted-light optical microscope using differential interference contrast (DIC) was employed to follow the real-time dynamics of different kb-sized single native dsDNA molecules without fluorescent-dye labeling. In a PDMS/glass microchip, the electrophoretic migration velocities of large dsDNA molecules are lower than small dsDNA molecules in a running buffer of 0.25% v/v nonionic polymeric surfactant C16E6 (n-alkyl polyoxyethylene ether) in 100 mM N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES) buffer because the C16E6 behaved as a dynamic polymer. However, the order of migration reversed in 50 mM Gly-Gly buffer. The radial positions of individual DNA molecules (i.e., center or walls of the microchip) did not change the migration order. The atypical migration order correlated well with the results in CE. The alignment of the deformable molecules due to viscous drag is likely responsible for these observations.

Buffers↗

PubMed2006

Modulation of immune responses induced by DNA vaccine expressing glycoprotein B of Pseudorabies Virus via coadministration of IFN-gamma-associated cytokines.

The immunomodulatory efficacy of interferon-gamma (IFN-gamma)-associated cytokines coadministered with a plasmid DNA vaccine has been investigated, with variable results. Therefore, to test the immunomodulatory effect of IFN-gamma-associated cytokines as vaccine adjuvant, the present study evaluated the immune responses induced by pseudorabies virus (PrV) gB-encoded plasmid DNA vaccine coadministered with IFN-gamma-associated cytokines and chemokines. These cytokines and chemokines included interleukin-12 (IL-12) and IL-18, as potent inducers of IFN-gamma, and IFN-gamma-inducible protein (IP-10), the production of which is IFN-gamma dependent. A coinjection of either IL-12 or IL-18 strongly suppressed the humoral antibody responses but increased the production of the Th1-type cytokines IFN-gamma and IL-2 from immune T cells. Such antibody suppression was closely related to the increased susceptibility against a virulent viral challenge. On the other hand, IP-10 exhibited enhanced immune responses in both antibody responses and IFN-gamma production of immune T cells and facilitated the prolonged survival of infected mice. In contrast, there was no significant change in the immune responses of the mice that received codelivery of IFN-gamma. Therefore, IFN-gamma-associated cytokines, as Th1-type inducers, can generate unexpected and unwanted effects, and their application as a vaccine adjuvant should be carefully evaluated depending on the target antigens.

Animals↗

PubMed2005

Microchip capillary gel electrophoresis using programmed field strength gradients for the ultra-fast analysis of genetically modified organisms in soybeans.

We have developed a novel method for the ultra-fast analysis of genetically modified organisms (GMOs) in soybeans by microchip capillary gel electrophoresis (MCGE) using programmed field strength gradients (PFSG) in a conventional glass double-T microchip. Under the programmed electric field strength and 0.3% poly(ethylene oxide) sieving matrix, the GMO in soybeans was analyzed within only 11 s of the microchip. The MCGE-PFSG method was a program that changes the electric field strength during GMO analysis, and was also applied to the ultra-fast analysis of PCR products. Compared to MCGE using a conventional and constantly applied electric field, the MCGE-PFSG analysis generated faster results without the loss of resolving power and reproducibility for specific DNA fragments (100- and 250-bp DNA) of GM-soybeans. The MCGE-PFSG technique may prove to be a new tool in the GMO analysis due to its speed, simplicity, and high efficiency.

DNA, Plant↗

PubMed2005

On-channel base stacking in microchip capillary gel electrophoresis for high-sensitivity DNA fragment analysis.

We evaluated a novel strategy for high-sensitivity DNA fragment analysis in a conventional glass double-T microfluidic chip. The microchip allows for a DNA on-channel concentration based on base stacking (BS) with a microchip capillary gel electrophoretic (MCGE) separation step in a poly(vinylpyrrolidone) (PVP) sieving matrix. Depending if low conductivity caused a neutralization reaction between the hydroxide ions and the run buffer component Tris+, the stacking of DNA fragments were processed in the microchip. Compared to a conventional MCGE separation with a normal electrokinetic injection, the peak heights of 50-2650-base pair (bp) DNA fragments on the MCGE-BS separation were increased 3.9-8.0-fold. When we applied the MCGE-BS method to the analysis of a clinical sample of bovine theileria after PCR reaction, the peak height intensity of the amplified 816-bp DNA fragment from the 18S rRNA of T. buffeli was enhanced 7.0-fold compared to that of the normal injection method.

DNA↗

PubMed2005

Separation of DNA fragments for fast diagnosis by microchip electrophoresis using programmed field strength gradient.

We evaluated a novel strategy for fast diagnosis by microchip electrophoresis (ME), using programmed field strength gradients (PFSG) in a conventional glass double-T microfluidic chip. The ME-PFSG allows for the ultrafast separation and enhanced resolving power for target DNA fragments. These results are based on electric field strength gradients (FSG) that use an ME separation step in a sieving gel matrix poly-(ethylene oxide). The gradient can develop staircase or programmed shapes FSG over the time. The PFSG method could be easily used to increase separation efficiency and resolution in ME separation of specific size DNA fragments. Compared to ME that uses a conventional and constantly applied electric field (isoelectrostatic) method, the ME-PFSG achieved about 15-fold faster analysis time during the separation of 100 bp DNA ladder. The ME-PFSG was also applied to the fast analysis of the PCR products, 591 and 1191 bp DNA fragments from the 18S rRNA of Babesia gibsoni and Babesia caballi.

Animals↗

PubMed2004

Direct observation of single native DNA molecules in a microchannel by differential interference contrast microscopy.

Direct observation of single native DNA molecules in a microchannel was monitored without fluorescence-dye labeling. At a PDMS/glass microchip, the image of individual lambda-DNA molecules appear sharp and distinct in Nomarski differential interference contrast microscopy. Intercalator dyes affected the physical properties and dynamic behavior of individual DNA molecules. From the migration velocities in the microchannel it is evident that native DNA molecules migrated faster than DNA molecules labeled with the intercalator YOYO-1. This is because YOYO-1 increases the molecular weight and size of lambda-DNA and decreases the charge. The electric field strength and pH also affected the dynamics of single DNA molecules. We also observed that YOYO-labeled DNA was more stretched out compared to native DNA.

Benzoxazoles↗

PubMed2002

Dynamics of single-protein molecules at a liquid/solid interface: implications in capillary electrophoresis and chromatography.

The behavior of individual molecules of R-phycoerythrin (RPE) was monitored by fluorescence imaging at various pHs and ionic strengths within the evanescent-field layer (EFL) at a water/fused-silica interface. Above the isoelectric point (pI), the individual protein molecules moved between exposures with random motion. As the pH approached the pI of the protein, the RPE molecules were partially adsorbed onto the fused-silica surface. The residence time and the number of molecules within the EFL also increased near the pI. Below the pI, the protein molecules were completely and permanently adsorbed onto the surface. However, the observed number of distinct molecule spots was decreased somewhat because of aggregation. At a given buffer condition, plots of residence times and molecule numbers exhibit asymmetry nearly identical to the corresponding elution peaks of the proteins in capillary electrophoresis and capillary liquid chromatography. These results provide insights into the fundamental interactions for the adsorption/desorption of proteins at the liquid/solid interface.

Chromatography↗