Antibody-Binding Motif of Mimetic Peptides to V. cholerae O139 Lipopolysaccharide

ABSTRACT This study explores deduced amino acid sequences of mimetic peptides of Vibrio cholerae O139 epitopes in order to design specific antigens for use in diagnostic method. Mimetic peptides expressed on E. coli flagella were selected from a FliTrx random peptide library via the interaction with purified monoclonal antibody to V. cholerae O139. Inserted nucleotides encoding bound peptides were determined by PCR. Peptides from clones giving positive results were confirmed by Western blot analysis. Sixty-two positive E. coli colonies were obtained and nucleotide-sequenced. Inserted nucleotides were translated into amino acids. Fifty-six patterns of deduced amino acid sequences were obtained without a consensus sequence. Most sequences of mimetic peptides have amino acid motif as RXXR with approximate molecular weight of 1,700 to 2,000. Arginine and glycine occupy the highest percentage of amino acid composition

Purification and Characterization of Fimbriae of Vibrio cholerae O1, Classical Biotype, Inaba Serotype

Fimbrial subunits have been shown to share common antigenicities between Vibrio cholerae biotype El Tor and biotype classical (Ehara et al., 1987). The above fact was confirmed by western blotting and immunoelectron microscopy. Net-work and bundle formations were observed in the fimbrial preparations by immunoelectron microscopy. Purified fimbriae of Vibrio cholerae O1, classical biotype possessed haemagglutination activity (HA) against chicken erythrocytes. This HA was inhibited in the presence of D-mannose but not by L-fucose. Antigenic determinants of the fimbriae were exposed on the sides of the fiber. The low hydrophobicity of the fimbriae molecule revealed by the amino acid composition suggests that the fimbriae may interact with epithelial cells not by hydrophobic interaction. Development of the antibody against fimbrial subunit of V. cholerae O1 was confirmed in the blood sera obtained from convalescent cholera patients

Prospective study of avian influenza virus infections among rural Thai villagers.

In 2008, 800 rural Thai adults living within Kamphaeng Phet Province were enrolled in a prospective cohort study of zoonotic influenza transmission. Serological analyses of enrollment sera suggested this cohort had experienced subclinical avian influenza virus (AIV) infections with H9N2 and H5N1 viruses.After enrollment, participants were contacted weekly for 24 mos for acute influenza-like illnesses (ILI). Cohort members confirmed to have influenza A infections were enrolled with their household contacts in a family transmission study involving paired sera and respiratory swab collections. Cohort members also provided sera at 12 and 24 months after enrollment. Serologic and real-time RT-PCR assays were performed against avian, swine, and human influenza viruses.Over the 2 yrs of follow-up, 81 ILI investigations in the cohort were conducted; 31 (38%) were identified as influenza A infections by qRT-PCR. Eighty-three household contacts were enrolled; 12 (14%) reported ILIs, and 11 (92%) of those were identified as influenza infections. A number of subjects were found to have slightly elevated antibodies against avian-like A/Hong Kong/1073/1999(H9N2) virus: 21 subjects (2.7%) at 12-months and 40 subjects (5.1%) at 24-months. Among these, two largely asymptomatic acute infections with H9N2 virus were detected by >4-fold increases in annual serologic titers (final titers 1:80). While controlling for age and influenza vaccine receipt, moderate poultry exposure was significantly associated with elevated H9N2 titers (adjusted OR = 2.3; 95% CI, 1.04-5.2) at the 24-month encounter. One subject had an elevated titer (1:20) against H5N1 during follow-up.From 2008-10, evidence for AIV infections was sparse among this rural population. Subclinical H9N2 AIV infections likely occurred, but serological results were confounded by antibody cross-reactions. There is a critical need for improved serological diagnostics to more accurately detect subclinical AIV infections in humans

High rate of A(H1N1)pdm09 infections among rural Thai villagers, 2009-2010.

Pandemic influenza A(H1N1)pdm09 emerged in Thailand in 2009. A prospective longitudinal adult cohort and household transmission study of influenza-like illness (ILI) was ongoing in rural Thailand at the time of emergence. Symptomatic and subclinical A(H1N1)pdm09 infection rates in the cohort and among household members were evaluated.A cohort of 800 Thai adults underwent active community-based surveillance for ILI from 2008-2010. Acute respiratory samples from ILI episodes were tested for A(H1N1)pdm09 by qRT-PCR; acute and 60-day convalescent blood samples were tested by A(H1N1)pdm09 hemagglutination inhibition assay (HI). Enrollment, 12-month and 24-month follow-up blood samples were tested for A(H1N1)pdm09 seroconversion by HI. Household members of influenza A-infected cohort subjects with ILI were enrolled in household transmission investigations in which day 0 and 60 blood samples and acute respiratory samples were tested by either qRT-PCR or HI for A(H1N1)pdm09. Seroconversion between annual blood samples without A(H1N1)pdm09-positive ILI was considered as subclinical infection.The 2-yr cumulative incidence of A(H1N1)pdm09 infection in the cohort in 2009/2010 was 10.8% (84/781) with an annual incidence of 1.2% in 2009 and 9.7% in 2010; 83.3% of infections were subclinical (50% in 2009 and 85.9% in 2010). The 2-yr cumulative incidence was lowest (5%) in adults born ≤ 1957. The A(H1N1)pdm09 secondary attack rate among household contacts was 47.2% (17/36); 47.1% of these infections were subclinical. The highest A(H1N1)pdm09 secondary attack rate among household contacts (70.6%, 12/17) occurred among children born between 1990 and 2003.Subclinical A(H1N1)pdm09 infections in Thai adults occurred frequently and accounted for a greater proportion of all A(H1N1)pdm09 infections than previously estimated. The role of subclinical infections in A(H1N1)pdm09 transmission has important implications in formulating strategies to predict and prevent the spread of A(H1N1)pdm09 and other influenza virus strains

Infectious Causes of Encephalitis and Meningoencephalitis in Thailand, 2003–2005

Acute encephalitis is a severe neurologic syndrome. Determining etiology from among ≈100 possible agents is difficult. To identify infectious etiologies of encephalitis in Thailand, we conducted surveillance in 7 hospitals during July 2003–August 2005 and selected patients with acute onset of brain dysfunction with fever or hypothermia and with abnormalities seen on neuroimages or electroencephalograms or with cerebrospinal fluid pleocytosis. Blood and cerebrospinal fluid were tested for >30 pathogens. Among 149 case-patients, median age was 12 (range 0–83) years, 84 (56%) were male, and 15 (10%) died. Etiology was confirmed or probable for 54 (36%) and possible or unknown for 95 (64%). Among confirmed or probable etiologies, the leading pathogens were Japanese encephalitis virus, enteroviruses, and Orientia tsutsugamushi. No samples were positive for chikungunya, Nipah, or West Nile viruses; Bartonella henselae; or malaria parasites. Although a broad range of infectious agents was identified, the etiology of most cases remains unknown

Risk factors for ≥4-fold increase in hemagglutination inhibition (HI) titer against A/Mexico/4108/2009(H1N1) from 2009 to 2010 among cohort subjects, Kamphaeng Phet, Thailand; odds ratios calculated by binary logistic regression.

<p>Abbreviation: OR, odds ratio; CI, confidence interval.</p>a<p>Covariate has some missing values.</p><p>Risk factors for ≥4-fold increase in hemagglutination inhibition (HI) titer against A/Mexico/4108/2009(H1N1) from 2009 to 2010 among cohort subjects, Kamphaeng Phet, Thailand; odds ratios calculated by binary logistic regression.</p

Risk factors for elevated antibodies against A/Hong Kong/1073/1999(H9N2), among adult participants, Thailand, 2010 (24-month follow-up visit) using binary logistic regression^a.

a<p>Binary logistic regression (Negative = H9N2 titer <1∶10, Positive = H9N2 titer ≥1∶10).</p>b<p>H3N2 antibody titer: Negative = titer <1∶40, Positive = titer ≥1∶40.</p>c<p>Covariate has missing data.</p

Evidence of A(H1N1)pdm09 infection among cohort subjects, Kamphaeng Phet, Thailand.

a<p>HI testing not conducted in some subjects due to insufficient serum volume.</p>b<p>≥4-fold increase in HI titer of 2009/2010 sera.</p>c<p>Positive respiratory sample for A(H1N1)pdm09 by qRT-PCR or ≥4-fold increase in HI titer of paired annual sera/paired ILI sera.</p>d<p>≥4-fold increase in HI titer of paired annual sera/paired ILI sera without positive respiratory sample for A(H1N1)pdm09 by qRT-PCR.</p><p>Evidence of A(H1N1)pdm09 infection among cohort subjects, Kamphaeng Phet, Thailand.</p