Last data update: Jun 24, 2024. (Total: 47078 publications since 2009)
Records 1-7 (of 7 Records) |
Query Trace: Nguyen DC [original query] |
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Zika preparedness and response in Viet Nam
Nguyen DT , Do HT , Le HX , Le NT , Vien MQ , Nguyen TB , Phan LT , Nguyen TV , Luong QC , Phan HC , Diep HT , Pham QD , Nguyen TV , Huynh LK , Nguyen DC , Pham HT , Ly KK , Tran HN , Tran PD , Dang TQ , Pham H , Vu LN , Mounts A , Balajee SA , Nolen LD . Western Pac Surveill Response J 2018 9 (2) 1-3 The findings and conclusions in this article are those of the authors and do not necessarily represent the official positions of the United States Centers for Disease Control and Prevention. |
Cynomolgus and pigtail macaque IgG subclasses: characterization of IGHG genes and computational analysis of IgG/Fc receptor binding affinity
Nguyen DC , Sanghvi R , Scinicariello F , Pulit-Penaloza J , Hill N , Attanasio R . Immunogenetics 2014 66 (6) 361-77 ![]() Macaques are the most widely used experimental nonhuman primate (NHP) species. Rhesus (Macaca mulatta, Macmul), cynomolgus (Macaca fascicularis, Macfas), and pigtail (Macaca nemestrina, Macnem) macaques continue to be popular models for vaccine and infectious diseases research, especially HIV infection and AIDS, and for the development of antibody-based therapeutic strategies. Increased understanding of the immune system of these species is necessary for their optimal use as models of human infections and intervention. In the past few years, the antibody/Fc receptor system has been characterized in a stepwise manner in these species. We have continued this characterization by identifying the four IG heavy gamma (IGHG) genes of Macfas and Macnem in this study. Our results show that these genes share a high degree of similarity with those from other NHP species, while presenting consistent differences when compared to human IGHG genes. Furthermore, comparison of Macfas IGHG genes with those described in other studies suggests the existence of polymorphism. Using sequence- and structure-based computational tools, we performed in silico analysis on multiple polymorphic Macfas IgG and their interactions with human IgG Fc receptors (FcgammaR), thus predicting that Macfas IGHG polymorphisms influence IgG protein stability and/or binding affinity towards FcgammaR. The presence of macaque IGHG polymorphisms and macaque/human amino acid changes at locations potentially involved in antibody functional properties indicate the need for cautious design and data interpretation of studies in these models, possibly requiring the characterization of antibody/Fc receptor interactions at the individual level. |
Seroprevalence of antibodies to avian influenza A (H5) and A (H9) viruses among market poultry workers, Hanoi, Vietnam, 2001
Uyeki TM , Nguyen DC , Rowe T , Lu X , Hu-Primmer J , Huynh LP , Hang NL , Katz JM . PLoS One 2012 7 (8) e43948 BACKGROUND: The frequency of avian influenza A virus infections among poultry workers is not well understood. METHODS: A seroprevalence study of market poultry workers and persons without occupational poultry exposure was conducted during 2001 in Hanoi, Vietnam. Sera were tested for avian influenza H5 and H9 antibodies by microneutralization and Western blot assays. RESULTS: Seroprevalence of H5 and H9 antibodies was 4% and 3% in poultry workers and 1% and 3.5% in non-poultry workers, respectively. CONCLUSIONS: Seroprevalence of H5 and H9 antibodies was low among Hanoi market poultry workers in 2001, but can serve as a baseline for additional studies. |
Pendrin mediates uptake of perchlorate in a mammalian in vitro system
Attanasio R , Scinicariello F , Blount BC , Valentin-Blasini L , Rogers KA , Nguyen DC , Murray HE . Chemosphere 2011 84 (10) 1484-8 Perchlorate is a known endocrine disruptor present in groundwater, vegetables and dairy food products in many regions of the United States. It interferes with the uptake of iodide into the thyrocyte by the sodium-iodide symporter at the basolateral surface, thus potentially disrupting the synthesis of thyroid hormone. Because transport of iodide from the thyroid follicular cells to the follicular lumen is mediated by the protein pendrin at the apical surface, we hypothesized that perchlorate may also interact with this protein. Therefore, HeLa cells were transfected with the human SLC26A4 gene, which encodes pendrin, to generate an in vitro mammalian system expressing the recombinant pendrin protein (HeLa-PDS). The HeLa-PDS cells, along with untransfected cells, were then cultured in presence of iodide and/or perchlorate. Intracellular levels of these two chemicals were measured by ion chromatography tandem mass spectrometry. Results from this study show that iodide and perchlorate uptake increases significantly in HeLa-PDS cells as compared to untransfected cells. Thus, recombinant HeLa cells expressing pendrin protein accumulate iodide and perchlorate intracellularly, indicating that pendrin is involved in the uptake of perchlorate. Additional results from this study suggest that iodide and perchlorate competitively inhibit each other for uptake by pendrin. The ability of perchlorate to compete with iodide for uptake by both basal and apical transporters may increase the potential of perturbation of thyroid homeostasis and therefore the estimated risk posed to susceptible human populations. |
Characterization and allelic polymorphisms of rhesus macaque (Macaca mulatta) IgG Fc receptor genes.
Nguyen DC , Scinicariello F , Attanasio R . Immunogenetics 2011 63 (6) 351-62 ![]() Macaque models are invaluable for AIDS research. Indeed, initial development of HIV-1 vaccines relies heavily on simian immunodeficiency virus-infected rhesus macaques. Neutralizing antibodies, a major component of anti-HIV protective responses, ultimately interact with Fc receptors on phagocytic and natural killer cells to eliminate the pathogen. Despite the major role that Fc receptors play in protective responses, there is very limited information available on these molecules in rhesus macaques. Therefore, in this study, rhesus macaque CD32 (FcgammaRII) and CD64 (FcgammaRI) homologues were genetically characterized. In addition, presence of CD16 (FcgammaRIII), CD32, and CD64 allelic polymorphisms were determined in a group of nine animals. Results from this study show that the predicted structures of macaque CD32 and CD64 are highly similar to their human counterparts. Macaque and human CD32 and CD64 extracellular domains are 88-90% and 94-95% homologous, respectively. Although all cysteines are conserved between the two species, macaque CD32 exhibits two additional N-linked glycosylation sites, whereas CD64 lacks three of them when compared to humans. Five CD32, three CD64, and three CD16 distinct allelic sequences were indentified in the nine animals examined, indicating a relatively high level of polymorphism in macaque Fcgamma receptors. Together, these results validate rhesus macaques as models for vaccine development and antibody responses, while at the same time, underscoring the need to take into account the high degree of genetic heterogeneity present in this species when designing experimental protocols. |
17beta-Estradiol restores antibody responses to an influenza vaccine in a postmenopausal mouse model
Nguyen DC , Masseoud F , Lu X , Scinicariello F , Sambhara S , Attanasio R . Vaccine 2011 29 (14) 2515-8 Post-menopausal women belong to an age group that is highly susceptible to influenza infection and its most serious complications. However, data on the immunogenicity of influenza vaccines in these women is limited. Therefore, the antibody response to influenza vaccination was assessed in a postmenopausal mouse model. An inactivated-detergent-split vaccine from the A/New Caledonia/20/99 (H1N1) influenza virus strain was given to three groups of mice: ovariectomized (OVEX), OVEX with 17beta-estradiol replacement (OVEX+E2), and sham-OVEX. The OVEX+E2 group produced influenza virus-specific serum antibodies, including neutralizing antibodies, at significantly higher levels (p<0.001) than did OVEX mice. These levels matched those observed in the sham-OVEX group, indicating that ovariectomy negatively modulates the antibody response to the influenza vaccine, whereas 17beta-estradiol replacement restores this response to levels observed in intact animals. Our findings suggest that immunogenicity and efficacy of influenza vaccines need to be evaluated in postmenopausal women, including women receiving hormone replacement therapy. |
Genetic analysis of avian influenza A viruses isolated from domestic waterfowl in live-bird markets of Hanoi, Vietnam, preceding fatal H5N1 human infections in 2004
Jadhao SJ , Nguyen DC , Uyeki TM , Shaw M , Maines T , Rowe T , Smith C , Huynh LP , Nghiem HK , Nguyen DH , Nguyen HK , Nguyen HH , Hoang LT , Nguyen T , Phuong LS , Klimov A , Tumpey TM , Cox NJ , Donis RO , Matsuoka Y , Katz JM . Arch Virol 2009 154 (8) 1249-61 ![]() The first known cases of human infection with highly pathogenic avian influenza (HPAI) H5N1 viruses in Vietnam occurred in late 2003. However, HPAI H5N1 and low-pathogenic avian influenza (LPAI) H5N2 and H9N3 viruses were isolated from domestic waterfowl during live-bird market (LBM) surveillance in Vietnam in 2001 and 2003. To understand the possible role of these early viruses in the genesis of H5N1 strains infecting people, we performed sequencing and molecular characterization. Phylogenetic analysis revealed that the hemagglutinin (HA) genes of two geese HPAI H5N1 strains belonged to clade 3, and their surface glycoprotein and replication complex genes were most closely related (98.5-99.7% homologous) to A/duck/Guangxi/22/01 (H5N1) virus, detected contemporarily in southern China, whilst the M and NS genes were derived from an A/duck/Hong Kong/2986.1/00 (H5N1)-like virus. The H5 HA gene of the duck HPAI H5N1 strain belonged to clade 5 and acquired a gene constellation from A/quail/Shantou/3846/02 (H5N1), A/teal/China/2978.1/02 (H5N1) and A/partridge/Shantou/2286/03 (H5N1)-like viruses. The phylogenetic analysis further indicated that all eight gene segments of goose and duck HPAI H5N1 and LPAI H5N2 viruses were distinct from those of H5N1 clade-1 viruses known to have caused fatal human infections in Vietnam since late 2003. The duck H9N3 isolates derived genes from aquatic-bird influenza viruses, and their H9 HA belonged to the Korean lineage. The PB2 gene of A/duck/Vietnam/340/01 (H9N3) virus had lysine at position 627. Based on the molecular characterization of specific amino acid residues in the surface and relevant internal protein-coding genes, the Vietnamese H5N1 and H9N3 virus isolates indicated specificity to avian cell surface receptor and susceptibility for currently licensed anti-influenza A virus chemotherapeutics. Our findings suggest that the H5N1 and H5N2 viruses that circulated among geese and ducks in LBMs in Hanoi, Vietnam, during 2001 and 2003 were not the immediate ancestors of the clade-1 viruses associated with fatal human infections in Vietnam. The clade-1 HPAI H5N1 viruses were independently introduced into Vietnam. |
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