7 research outputs found

    Proteomic Analysis of Urine Exosomes Reveals Renal Tubule Response to Leptospiral Colonization in Experimentally Infected Rats

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    <div><p>Background</p><p>Infectious <i>Leptospira</i> colonize the kidneys of reservoir (e.g. rats) and accidental hosts such as humans. The renal response to persistent leptospiral colonization, as measured by urinary protein biosignatures, has not been systematically studied. Urinary exosomes--bioactive membrane-bound nanovesicles--contain cell-state specific cargo that additively reflect formation all along the nephron. We hypothesized that <i>Leptospira</i>-infection will alter the content of urine exosomes, and further, that these <i>Leptospira</i>-induced alterations will hold clues to unravel novel pathways related to bacterial-host interactions.</p><p>Methodology/Principal findings</p><p>Exosome protein content from 24 hour urine samples of <i>Leptospira</i>-infected rats was compared with that of uninfected rats using SDS-PAGE and liquid chromatography/tandem mass spectrometry (LC-MS/MS). Statistical models were used to identify significantly dysregulated proteins in <i>Leptospira</i>-infected and uninfected rat urine exosomes. In all, 842 proteins were identified by LC-MS/MS proteomics of total rat urine and 204 proteins associated specifically with exosomes. Multivariate analysis showed that 25 proteins significantly discriminated between uninfected control and infected rats. Alanyl (membrane) aminopeptidase, also known as CD13 topped this list with the highest score, a finding we validated by Western immunoblotting. Whole urine analysis showed Tamm-Horsfall protein level reduction in the infected rat urine. Total urine and exosome proteins were significantly different in male vs. female infected rats.</p><p>Conclusions</p><p>We identified exosome-associated renal tubule-specific responses to <i>Leptospira</i> infection in a rat chronic colonization model. Quantitative differences in infected male and female rat urine exosome proteins vs. uninfected controls suggest that urine exosome analysis identifies important differences in kidney function that may be of clinical and pathological significance.</p></div

    Risk of COVID-19 after natural infection or vaccinationResearch in context

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    Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health
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