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Chiou-Ying Yang

Publications and source records attributed to Chiou-Ying Yang.

9 recordsLinked to original sources
PubMed2007

Functional epitopes on porcine endogenous retrovirus envelope protein interacting with neutralizing antibody combining sites.

Porcine cell and organ transplantation provides promise for maintaining normal physiological conditions in patients with end-stage organ failure. The approach however poses serious risk of transmitting pig pathogens to humans. Among many potential pathogens, porcine endogenous retroviruses (PERV) are of particular concern due to their ubiquitous nature in pigs and capability of infecting human cells. Major antigenic determinants and receptor binding domains on PERV remain unclear until now. Two monoclonal antibodies (mAb), named 8E10 and 7C4 capable of neutralizing PERV infection in HEK293 cells are isolated at an IC(50) of 3.0 and 2.7 microg/ml, respectively, in this work. Epitope location for mAb 8E10 was mapped to amino acids 427-434, residing at the C-terminal region of the gp70 component of type A PERV Env protein. The mAb 8E10 bound directly to the PERV indicating that the epitope is exposed on the virion surface. The mAb 7C4 epitope was assigned to the region comprising amino acids 517-537 on the p15E component of PERV. In contrast to mAb 8E10, the 7C4 mAb bound native PERV inefficiently suggesting that its epitope is accessible only after the virus interacts with its receptor. Finally, both mAbs variable regions were cloned and nucleotide sequence determined. All together, these results reveal that both mAbs 8E10 and 7C4 effectively neutralize PERV infection and may be used as a mean to prevent PERV infection in patients receiving xenotransplantation.

Amino Acid Sequence↗
PubMed2006

Production of target-specific recombinant human polyclonal antibodies in mammalian cells.

We describe the expression and consistent production of a first target-specific recombinant human polyclonal antibody. An anti-Rhesus D recombinant polyclonal antibody, Sym001, comprised of 25 unique human IgG1 antibodies, was produced by the novel Sympress expression technology. This strategy is based on site-specific integration of antibody genes in CHO cells, using the FRT/Flp-In recombinase system. This allows integration of the expression construct at the same genomic site in the host cells, thereby reducing genomic position effects. Different bioreactor batches of Sym001 displayed highly consistent manufacturing yield, antibody composition, binding potency, and functional activity. The results demonstrate that diverse recombinant human polyclonal antibody compositions can be reproducibly generated under conditions directly applicable to industrial manufacturing settings and present a first recombinant polyclonal antibody which could be used for treatment of hemolytic disease of the newborn and/or idiopathic thrombocytopenic purpura.

Animals↗
PubMed2006

Antigenic diversity of Neisseria meningitidis isolated in Taiwan between 1995 and 2002.

The geographic distribution of N. meningitidis is diverse. Information on the antigenic variation of N. meningitidis is important for the development of an outer membrane protein-based vaccine. As a first step towards vaccine development, serological typing was performed to determine the antigenic properties of 127 invasive N. meningitidis isolates collected in Taiwan between 1995 and 2002. With 31.5% non-serotypeable and 32.3% non-serosubtypeable, the 127 isolates fell into 51 phenotypes, with W135:NT:P1.5,2:L3,7,9, Y:14P1.5,2, and B:1:NST:L3,7,9 being the 3 most prevalent. Among the 37 serogroup B isolates, 15 serosubtypes were found, with P1.5,2 and P1.12,13 being the most prevalent. The high diversity of Por A among serogroup B isolates circulating in Taiwan poses a great challenge for the development of a PorA-based vaccine. Because 85% of the serogroup B isolates had the L3,7,9 immunotype, inclusion of L3,7,9 lipooligosaccharides in a PorA-based vaccine may be a promising approach. In addition, based on the phenotypic characterization, we suggest that both serogroup B and W135 isolates were endemic and that serogroup A, C, and Y isolates were imported, which may reflect increased international travel.

Enzyme-Linked Immunosorbent Assay↗
PubMed2005

Prognostic significance of intratumoral natural killer cells in primary resected esophageal squamous cell carcinoma.

BACKGROUND: Natural killer (NK) cells are important effector cells in the defense against tumors. The present study retrospectively examines the intratumoral NK cells in primary resected esophageal squamous cell carcinoma (ESCC) and the correlation between the patient' outcome and the intratumoral NK cells infiltration. METHODS: Immunohistochemistry was used to analyze the intratumoral NK cell infiltration in 38 archival specimens from patients with primary resected ESCC. RESULTS: According to the cut-off point of the staining for intratumoral NK cell infiltration, 14 (37%) cases had high level infiltration and 24 (63%) low. The 5-year survival of patients with high level NK infiltration was significantly better than that of patients with a low level of NK infiltration (p < 0.01). Multivariate analysis did not show NK cell infiltration to be a significant prognostic factor. CONCLUSIONS: Intratumoral NK cell infiltration is associated with a favorable outcome in ESCC. Intratumoral NK cell infiltration might be used as a variable with prognostic value in primary resected ESCC.

Adult↗
PubMed2003

Identification of the antigenic determinants of the American cockroach allergen Per a 1 by error-prone PCR.

The group I allergen of cockroach is found in both American and German cockroaches, designated as Per a 1 and Bla g 1, respectively. Members of these allergens so far identified are composed of tandem repeats that may cause the high allergenicity of Per a 1 allergen. In this study, we used monoclonal antibodies HW-8 and HW-19, which can inhibit the binding of patient IgE to Per a 1 allergen, to define the structure of the antigenic determinants in Per a 1.0103 (designated C3), an isoallergen of Per a 1 allergen. Two recognition sites are present, one in the N-terminus (aa 1-208) and the other in the C-terminus (aa 208-395). The N-terminal epitope is not accessible to antibody molecules on the pET-expressed C3 protein. The C-terminal epitope was further localized to the aa 267-354 region (C3E) by colony immunoscreening of the cDNA epitope library. By negative screening of the mutated C3E expression library generated by error-prone PCR (ER-PCR), an approach which has rarely been applied in epitope mapping, the functional epitope was identified to lie in aa 318-337 with aa 323-331 being the core motif. The minimal region of the functional epitope was further delineated, by sequence alignment, to be D-x-[I, L]-A-[I, L]-L-P-V-D-E-[L, I]-x-A-[L, I], where x represents any amino acids. This motif is found in all Per a 1 allergens and may serve as a basis for designing a peptide vaccine for allergen-specific immunotherapy. To our knowledge, this is the first report for (1) detailed mapping of the cockroach allergens and (2) use of error-prone PCR random mutagenesis and negative selection in molecular allergology.

Allergens↗
PubMed2003

Involvement of tonB-exbBD1D2 operon in infection of Xanthomonas campestris phage phi L7.

phi L7 is a lytic bacteriophage infecting Xanthomonas campestris pv. campestris, a Gram-negative bacterium producing xanthan gum and causing black rot in crucifers. A mutant resistant to phi L7 was isolated by Tn5 mutagenesis. Sequence analysis indicated that the gene responsible for the mutation is tonB encoding an inner membrane protein previously shown to be required for iron uptake and pathogenesis. This gene is clustered with three other genes, tonB-exbB-exbD1-exbD2. Results of insertional mutations, DNA and protein sequence analyses, phage sensitivity tests, transfection tests, complementation tests, and phage adsorption assays together with the cellular location of the proteins indicate that TonB, ExbB, and ExbD1 are essential for penetration of phage phi L7. The genome organization, structural features of the tonB-exb region, and transcriptional analyses including Northern hybridization, reporter assays, and primer extension together indicate that the four genes are organized into an operon.

Amino Acid Sequence↗
PubMed2003

Polyclonal Fab phage display libraries with a high percentage of diverse clones to Cryptosporidium parvum glycoproteins.

The protozoan parasite Cryptosporidium parvum is regarded as a major public health problem world-wide, especially for immunocompromised individuals. Although no effective therapy is presently available, specific immune responses prevent or terminate cryptosporidiosis and passively administered antibodies have been found to reduce the severity of infection. Therefore, as an immunotherapeutic approach against cryptosporidiosis, we set out to develop C. parvum-specific polyclonal antibody libraries, standardised, perpetual mixtures of polyclonal antibodies, for which the genes are available. A combinatorial Fab phage display library was generated from the antibody variable region gene repertoire of mice immunised with C. parvum surface and apical complex glycoproteins which are believed to be involved in mediating C. parvum attachment and invasion. The variable region genes used to construct this starting library were shown to be diverse by nucleotide sequencing. The library was subjected to one round of antigen selection on C. parvum glycoproteins or a C. parvum oocyst/sporozoite preparation. The two selected libraries showed specific reactivity to the glycoproteins as well as to the oocyst/sporozoite preparation, with 50-73% antigen-reactive members. Fingerprint analysis of individual clones from the two antigen-selected libraries showed high diversity, confirming the polyclonality of the selected libraries. Furthermore, immunoblot analysis on the oocyst/sporozoite and glycoprotein preparations with selected library phage showed reactivity to multiple bands, indicating diversity at the antigen level. These C. parvum-specific polyclonal Fab phage display libraries will be converted to libraries of polyclonal full-length antibodies by mass transfer of the selected heavy and light chain variable region gene pairs to a mammalian expression vector. Such polyclonal antibody libraries would be expected to mediate effector functions and provide optimal passive immunity against cryptosporidiosis.

Animals↗
PubMed2003

Molecular epidemiology of Bordetella pertussis isolated in Taiwan, 1992-1997.

In Taiwan, the number of pertussis cases including various types of infection has been increasing in recent years, especially in 1997. Since 71% of the reported cases concentrated in the densely populated Taipei metropolitan area, concerns have been raised that a highly contagious strain of Bordetella pertussis might have appeared in Taipei. In this study, 114 strains of B. pertussis including those isolated in 1992-1996 (n = 53) and 1997 (n = 61) were subjected to pulsed-field gel electrophoresis (PFGE) of the Xba I digests from their chromosomes. Based on the band patterns, they were divided into 21 subtypes, P1 to P21. The strains isolated in 1997 consist of 17 subtypes including 9 new subtypes which did not appear in the previous years, indicating that the outbreaks in 1997 were not caused by a sole specific virulent strain. Dendrogram analysis indicated that the 21 subtypes can be grouped into five clusters, with the first four subtypes possessing 60 to 95% relatedness to one another, whereas relatedness between cluster 5 (containing P21 only) and the other clusters is less than 50%. Notably, all the subtypes except P12 and P21 appeared at least once in Taipei and the majority of the strains (54%) belong to two clusters, 3 and 4. These results suggest that highly dense population may facilitate spread and accelerate genetic divergence of this pathogen. This is the first report on pertussis molecular epidemiology in Taiwan.

Bacterial Typing Techniques↗