14 research outputs found

    Karistuslik kahjuhüvitis - kas üksnes common law fenomen?

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    http://tartu.ester.ee/record=b2612445~S1*es

    Naturally Acquired Human Immunity to Pneumococcus Is Dependent on Antibody to Protein Antigens

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    Naturally acquired immunity against invasive pneumococcal disease (IPD) is thought to be dependent on anti-capsular antibody. However nasopharyngeal colonisation by Streptococcus pneumoniae also induces antibody to protein antigens that could be protective. We have used human intravenous immunoglobulin preparation (IVIG), representing natural IgG responses to S. pneumoniae, to identify the classes of antigens that are functionally relevant for immunity to IPD. IgG in IVIG recognised capsular antigen and multiple S. pneumoniae protein antigens, with highly conserved patterns between different geographical sources of pooled human IgG. Incubation of S. pneumoniae in IVIG resulted in IgG binding to the bacteria, formation of bacterial aggregates, and enhanced phagocytosis even for unencapsulated S. pneumoniae strains, demonstrating the capsule was unlikely to be the dominant protective antigen. IgG binding to S. pneumoniae incubated in IVIG was reduced after partial chemical or genetic removal of bacterial surface proteins, and increased against a Streptococcus mitis strain expressing the S. pneumoniae protein PspC. In contrast, depletion of type-specific capsular antibody from IVIG did not affect IgG binding, opsonophagocytosis, or protection by passive vaccination against IPD in murine models. These results demonstrate that naturally acquired protection against IPD largely depends on antibody to protein antigens rather than the capsule

    Pandemic response gaps: Infection prevention and control lessons learned during coronavirus disease 2019 (COVID-19) outbreaks in skilled nursing facilities in Detroit, Michigan

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    BACKGROUND: Hospitalizations among skilled nursing facility (SNF) residents in Detroit increased in mid-March 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. Outbreak response teams were deployed from local healthcare systems, the Centers for Disease Control and Prevention (CDC), and the Detroit Health Department (DHD) to understand the infection prevention and control (IPC) gaps in SNFs that may have accelerated the outbreak. METHODS: We conducted 2 point-prevalence surveys (PPS-1 and PPS-2) at 13 Detroit SNFs from April 8 to May 8, 2020. The DHD and partners conducted facility-wide severe acute respiratory coronavirus virus 2 (SARS-CoV-2) testing of all residents and staff and collected information regarding resident cohorting, staff cohorting, and personnel protective equipment (PPE) utilized during that time. RESULTS: Resident cohorting had been implemented in 7 of 13 (58.3%) SNFs prior to point-prevalence survey 1 (PPS-1), and other facilities initiated cohorting after obtaining PPS-1 results. Cohorting protocols of healthcare practitioners and environmental service staff were not established in 4 (31%) of 13 facilities, and in 3 facilities (23.1%) the ancillary staff were not assigned to cohorts. Also, 2 SNFs (15%) had an observation unit prior to PPS-1, 2 (15%) had an observation unit after PPS-1, 4 (31%) could not establish an observation unit due to inadequate space, and 5 (38.4%) created an observation unit after PPS-2. CONCLUSION: On-site consultations identified gaps in IPC knowledge and cohorting that may have contributed to ongoing transmission of SARS-CoV-2 among SNF residents despite aggressive testing measures. Infection preventionists (IPs) are critical in guiding ongoing IPC practices in SNFs to reduce spread of COVID-19 through response and prevention

    IVIG improves macrophage and neutrophil opsonophagocytosis of both encapsulated an unencapsulated <i>S</i>. <i>pneumoniae</i> TIGR4.

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    <p>(<b>A</b>) MFI and example of a histogram of the fluorescence of RAW macrophages incubated with fluorescent (FAM-SE labelled) encapsulated (clear columns) and unencapsulated (black columns) <i>S</i>. <i>pneumoniae</i> TIGR4 strains with and without addition of 10% IVIG. <i>P</i> values were calculated using unpaired 2-tailed Student t-test. <b>(B</b>) MFI of fluorescence intensity of human neutrophils following incubation with FAM-SE labelled <i>S</i>. <i>pneumoniae</i> TIGR4 encapsulated (clear columns) and unencapsulated (filled columns) strains pre-opsonised with increasing concentrations of IVIG. <i>P</i> values were calculated using one-way ANOVAs. (<b>C</b>) Relative survival of <i>S</i>. <i>pneumoniae</i> TIGR4 encapsulated (+cps) and unencapsulated (-cps) strains following incubation with human neutrophils in the presence of 10% IVIG. Percentage survival calculated relative to survival of identical strain incubated without IVIG, with the surviving CFU / ml shown for control versus 10% IVIG above each column. For all panels, data are presented as means and SDs of three to four technical replicates and are representative of experiments repeated at least twice. <i>P</i> values were calculated using unpaired 2-tailed Student t-test (<b>A</b> and <b>C</b>) or one way ANOVAs (<b>B</b>).</p

    Passive vaccination with IVIG protects against IPD in murine models of <i>S</i>. <i>pneumoniae</i> infection.

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    <p>Mice were passively vaccinated by i.p. administration of 12.8 mg of IVIG (Intratect) or PBS 3 hours before challenge with <i>S</i>. <i>pneumoniae</i>. (<b>A</b>) and <b>(B)</b> Concentration of human IgG measured by ELISA after <b>(A)</b> in mouse sera 3 h post-IVIG (n = 4), and (<b>B</b>) in mouse BALF recovered from mice 3 h post-IVIG and immediately before and at 2.5 and 24 h after i.n. challenge with 10<sup>7</sup> CFU of TIGR4 strain <i>S</i>. <i>pneumoniae</i> (n = 4 to 6). <b>(C)</b> Correlation between concentration of murine albumin (mg/ml) and human IgG (μg/ml) in BALF 24 hr following invasive i.n. challenge in IVIG-treated mice (n = 6); <i>P</i> and r<sup>2</sup> values were calculated using the F test. <b>(D)</b> Bacterial CFU (log<sub>10</sub>) recovered from BALF 2.5 hr following IN challenge with 5x10<sup>5</sup> CFU of TIGR4 of IVIG-treated or PBS-treated control mice (n = 6 or 7). <b>(E)</b> Bacterial CFU (log<sub>10</sub>) recovered from BALF, lung tissue or blood 24 hr following IN challenge with 10<sup>7</sup> CFU of TIGR4 of IVIG-treated or PBS-treated control mice (n = 6). <b>(F)</b> Bacterial CFU (log<sub>10</sub>) recovered from blood 4 hr following i.v. challenge with 5x10<sup>5</sup> CFU of TIGR4 of IVIG-treated or PBS-treated mice (n = 5). <b>(G)</b> Effect of administration of i.v. 100 μl liposomal clodronate (5mg/ml) to mice on the numbers of F4/80+ve splenocytes measured by flow cytometry (n = 6), with data presented as means, error bars represent SDs, and <i>P</i> values were calculated using unpaired 2-tail Student t-test. <b>(H)</b> Effect of clodronate or PBS administration on bacterial CFU (log<sub>10</sub>) recovered from the blood of IVIG-treated mice 4 hr following i.v. challenge with 5x10<sup>5</sup> CFU of TIGR4 (n = 5). (<b>I)</b> Bacterial CFU (log<sub>10</sub>) recovered from the lungs of neutrophil depleted mice (by prior treatment with the antiLy6 antibody 1A8) given either IVIG or PBS 24 hr and then inoculated i.n. with 5x10<sup>6</sup> CFU of TIGR4 (n = 11 or 12). For <b>(A, B, D, E, F, H, I)</b>, symbols represent data from individual mice, bars represent group means, and <i>P</i> values were calculated using unpaired 2-tail Student t-test. Dashed lines represent the limit of detection.</p

    eIVIG immune recognition of <i>S</i>. <i>pneumoniae</i>.

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    <p><b>(A-D)</b> Whole cell ELISAs of IgG binding to solid-phase <i>S</i>. <i>pneumoniae</i> of increasing concentrations of eIVIG made using TIGR4 <b>(A and B)</b> or D39 <b>(C</b> and <b>D)</b> or IVIG. Binding was assessed to the solid phase strain that was homologous (<b>A</b> and <b>D</b>) or heterologous (<b>B</b> and <b>C</b>) to the enrichment strain. (<b>E-F</b>) Bacterial surface IgG binding measured by flow cytometry to <i>S</i>. <i>pneumoniae</i> TIGR4 <b>(E)</b> or D39 <b>(F)</b> incubated in either PBS (shaded area) or TIGR4 eIVIG at 30 μg/ml (solid line). <i>P</i> values were calculated using linear regression for panels A, B, C, and D, and unpaired 2-tailed Student t-tests for panels E and F.</p

    IgG binding to live <i>S</i>. <i>pneumoniae</i> after incubation with IVIG.

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    <p>(<b>A</b>) Effect of presence (wild-type strain, +cps) or absence (unencapsulated strain, -cps) of the capsule on IgG binding to live <i>S</i>. <i>pneumoniae</i> TIGR4 incubated in either 1% IVIG, 10% IVIG or PBS (control). IgG binding was measured as MFI using anti-IgG-PE by flow cytometry. (<b>B</b>) Effect of presence or absence of capsule on IgG binding to 3 other serotype strains (ST2, strain D39; ST23F; ST3, strain 0100993) incubated in 10% IVIG. (<b>C</b>) Effect of pre-treatment of bacteria with Pronase or PBS prior to incubation in 10% IVIG on IgG binding to TIGR4, and an example of the histogram for IgG binding MFI (solid line, PBS then IVIG; dotted line PBS then Pronase then IVIG; shaded area, no IVIG). <b>(D)</b> Effect of loss of expression of lipoproteins (<i>Δlgt</i>) or both the choline binding proteins PspA and PspC (<i>ΔpspA/pspC</i>) on IgG binding to the D39 strain after incubation in 10% IVIG, with an example of the histogram for the MFI of IgG binding (solid line, <i>Δlgt</i>; dotted line, <i>ΔpspA/pspC</i>; shaded area, D39). <b>(E)</b> Effect of depletion of specific surface protein antibodies from 10% IVIG using absorption with unencapsulated TIGR4 prior to incubating wild type TIGR4 bacteria in IVIG and measuring IgG binding using flow cytometry. <b>(F)</b> and <b>(G)</b> Effect of expressing potential <i>S</i>. <i>pneumoniae</i> antigens in <i>S</i>. <i>mitis</i> on IgG binding to live bacteria after incubation in 10% IVIG. (<b>F</b>) IgG binding to wild-type <i>S</i>. <i>mitis</i> (WT), <i>S</i>. <i>mitis</i> manipulated to lacking its own capsule (Δcps) or expressing <i>S</i>. <i>pneumoniae</i> serotype 4 capsule (T4cps). (<b>G</b>) IgG binding to wild-type <i>S</i>. <i>mitis</i> (WT) or <i>S</i>. <i>mitis</i> expressing PspC. For all panels, data are presented as means and SDs of three to four technical replicates and are representative of experiments repeated at least twice. <i>P</i> values were calculated using unpaired 2-tailed Student t-tests.</p

    Identification of protein antigens recognised by different sources of pooled IgG.

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    <p>(<b>A</b>) Immunoblots of IgG (1/1000) binding to the wild-type <i>S</i>. <i>pneumoniae</i> strain D39 and isogenic mutant strains (10 μg) lacking specific surface proteins using IVIG. Boxes highlight missing bands corresponding to the molecular weight for the protein(s) absent in the mutant strains. (<b>B</b>) Immunoblots of IgG binding to selected recombinant <i>S</i>. <i>pneumoniae</i> proteins (0.5 μg / lane) probed with IVIG (1/500). (<b>C</b>) Immunoblots of IgG binding to wild-type <i>S</i>. <i>pneumoniae</i> D39 strain (10 μg / lane) using pooled sera from different geographical regions, commercial IVIG (1/3300) from Europe (Intratect) or USA (Vigam) and from Malawi. (<b>D</b>) Linear regression of the rank order of strength of IgG binding to different protein antigens between serum pooled from donors from Malawi and IVIG preparations obtained from the USA (Vigam) or Europe (Intratect). Data points represent the rank order of each protein antigen for the mean MFI of two technical duplicates for IgG binding measured using the Luminex assay. <i>P</i> and R<sup>2</sup> values were obtained using F tests.</p

    Absorption of anti-capsular antibody does not prevent IVIG protection against murine models of IPD.

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    <p><b>(A)</b> Mean (SD) anti-PsaA titres measured by ELISA in IVIG following depletion of type 4 specific IgG by pre-absorption with type 4 capsule expressing <i>S</i>. <i>mitis</i>. (<b>B</b>) Mean (SD) anti-capsular serotype 4 titre IgG titre measured by ELISA in type 4 specific IgG-depleted IVIG. (<b>B</b>) Mean (SD) MFI of anti-human IgG binding to wild-type (clear columns) and unencapsulated (black columns) <i>S</i>. <i>pneumoniae</i> TIGR4 following incubation in 1% or 10% in type 4 specific IgG-depleted IVIG. (<b>C</b>) Bacterial surface IgG binding measured by flow cytometry to <i>S</i>. <i>pneumoniae</i> TIGR4 incubated in PBS (grey column), 1% or 10% mock absorbed IVIG with (filled columns) or type 4 specific IgG-depleted IVIG (open columns). For panels (A) to (C) data are presented as means and SDs of three to four technical replicates and representative of experiments repeated at least twice. (<b>D</b>) Log<sub>10</sub> CFU recovered from BALF, lungs, and blood 24 h after i.n. challenge with 1x10<sup>7</sup> CFU <i>S</i>. <i>pneumoniae</i> TIGR4 for mice pre-treated with 12.8 mg of type 4 specific IgG-depleted IVIG or PBS. (<b>E</b>) Log<sub>10</sub> CFU recovered from blood 4 h after i.v. challenge with 5x10<sup>5</sup> CFU <i>S</i>. <i>pneumoniae</i> TIGR4 for mice pre-treated with PBS (open circles), or 12.8 mg of mock absorbed IVIG (black circles) or type 4 specific IgG-depleted IVIG (grey circles). Data for panels <b>(D)</b> and <b>(E)</b> were obtained using IVIG depleted of capsular antibody on separate occasions; symbols represent data from individual mice, bars represent group means, and <i>P</i> values were calculated using unpaired 2-tail Student t-test <b>(D)</b> or one way ANOVA <b>(E).</b> Dashed lines represent the limit of detection.</p
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