lipid-a and Gastroenteritis

Acute norovirus gastroenteritis causes significant morbidity and in uncommon cases fatality in older adults. We investigated the safety and immunogenicity of bivalent virus-like particle (VLP) vaccine candidate formulations with and without monophosphoryl lipid A (adjuvant MPL) in this population.. In this phase II, double-blind, controlled trial 294 healthy adults, ≥ 60 years of age, were randomized (1:1:1:1) to four groups to receive one or two intramuscular immunizations 28 days apart, with 26 18-49 year-old controls who received one MPL-free dose. One-dose groups received placebo on Day 1. Vaccine formulations contained 15 μg GI.1 and 50 μg GII.4c VLP antigens and 500 μg Al(OH). After one dose HBGA antibodies to both VLP antigens increased with similar kinetics and magnitude in all groups; geometric mean titres (GMTs) persisted above baseline through Day 393. GMTs were similar across age strata (18-49, 60-74, 75-84 and ≥ 85 years of age) and unaffected by a second vaccination or MPL. Total Ig showed similar responses. No clinically relevant differences or changes in avidity or CMI were observed between formulations. Both formulations were well tolerated with no vaccine-related SAEs, the most frequent AEs being mild injection site pain and fatigue.. Adults over 60 years of age displayed no safety concerns and had similar immune responses to the norovirus VLP vaccine candidate as younger adults, unaffected by increasing age, a second dose or inclusion of MPL. This data supports the further development of the MPL-free vaccine candidate for older adults.

Topics: Aged; Aged, 80 and over; Antibodies, Viral; Double-Blind Method; Gastroenteritis; Humans; Lipid A; Middle Aged; Norovirus; Receptors, Thrombopoietin; Vaccines, Virus-Like Particle

Vaccines against norovirus, the leading cause of acute gastroenteritis, should protect against medically significant illness and reduce transmission.. In this randomized, double-blind, placebo-controlled trial, 18- to 50-year-olds received 2 injections of placebo or norovirus GI.1/GII.4 bivalent vaccine-like particle (VLP) vaccine with 3-O-desacyl-4'-monophosphoryl lipid A (MPL) and alum. Participants were challenged as inpatients with GII.4 virus (4400 reverse transcription polymerase chain reaction [RT-PCR] units), and monitored for illness and infection.. Per protocol, 27 of 50 (54.0%) vaccinees and 30 of 48 (62.5%) controls were infected. Using predefined illness and infection definitions, vaccination did not meet the primary endpoint, but self-reported cases of severe (0% vaccinees vs. 8.3% controls; P = .054), moderate or greater (6.0% vs. 18.8%; P = .068), and mild or greater severity of vomiting and/or diarrhea (20.0% vs. 37.5%; P = .074) were less frequent. Vaccination also reduced the modified Vesikari score from 7.3 to 4.5 (P = .002). Difficulties encountered were low norovirus disease rate, and inability to define illness by quantitative RT-PCR or further antibody rise in vaccinees due to high vaccine-induced titers. By day 10, 11 of 49 (22.4%) vaccinees were shedding virus compared with 17 of 47 (36.2%) placebo recipients (P = .179).. Bivalent norovirus VLP vaccine reduced norovirus-related vomiting and/or diarrhea; field efficacy studies are planned. Clinical Trials Registration. NCT01609257.

Topics: Adjuvants, Immunologic; Adolescent; Adult; Caliciviridae Infections; Double-Blind Method; Female; Gastroenteritis; Humans; Lipid A; Male; Middle Aged; Norovirus; Vaccination; Viral Load; Viral Vaccines; Young Adult

Noroviruses cause significant morbidity and mortality from acute gastroenteritis in all age groups worldwide.. We conducted 2 phase 1 double-blind, controlled studies of a virus-like particle (VLP) vaccine derived from norovirus GI.1 genotype adjuvanted with monophosphoryl lipid A (MPL) and the mucoadherent chitosan. Healthy subjects 18-49 years of age were randomized to 2 doses of intranasal Norwalk VLP vaccine or controls 21 days apart. Study 1 evaluated 5-, 15-, and 50-μg dosages of Norwalk antigen, and study 2 evaluated 50- and 100-μg dosages. Volunteers recorded symptoms for 7 days after dosing, and safety was followed up for 180 days. Blood samples were collected for serological profile, antibody secreting cells (ASCs), and analysis of ASC homing receptors.. The most common symptoms were nasal stuffiness, discharge, and sneezing. No vaccine-related serious adverse events occurred. Norwalk VLP-specific immunoglobulin G and immunoglobulin A antibodies increased 4.8- and 9.1-fold, respectively, for the 100-μg dosage level. All subjects tested who received the 50- or 100-μg vaccine dose developed immunoglobulin A ASCs. These cells expressed molecules associated with homing to mucosal and peripheral lymphoid tissues.. The intranasal monovalent adjuvanted Norwalk VLP vaccine was well tolerated and highly immunogenic and is a candidate for additional study.

Topics: Adjuvants, Immunologic; Administration, Intranasal; Adolescent; Adult; Antibodies, Viral; Antibody-Producing Cells; Caliciviridae Infections; Chitosan; Double-Blind Method; Gastroenteritis; Hemagglutination Inhibition Tests; Humans; Lipid A; Lymphoid Tissue; Middle Aged; Mucous Membrane; Norwalk virus; Receptors, Lymphocyte Homing; Viral Vaccines; Young Adult

In bacteria, the RNA chaperone Hfq enables pairing of small regulatory RNAs with their target mRNAs and therefore is a key player of post-transcriptional regulation network. As a global regulator, Hfq is engaged in the adaptation to external environment, regulation of metabolism and bacterial virulence. In this study we used RNA-sequencing and quantitative proteomics (LC-MS/MS) to elucidate the role of this chaperone in the physiology and virulence of Yersinia enterocolitica serotype O:3. This global approach revealed the profound impact of Hfq on gene and protein expression. Furthermore, the role of Hfq in the cell morphology, metabolism, cell wall integrity, resistance to external stresses and pathogenicity was evaluated. Importantly, our results revealed that several alterations typical for the hfq-negative phenotype were due to derepression of the transcriptional factor RovM. The overexpression of RovM caused by the loss of Hfq chaperone resulted in extended growth defect, alterations in the lipid A structure, motility and biofilm formation defects, as well as changes in mannitol utilization. Furthermore, in Y. enterocolitica RovM only in the presence of Hfq affected the abundance of RpoS. Finally, the impact of hfq and rovM mutations on the virulence was assessed in the mouse infection model.

Topics: Animals; Bacterial Proteins; Base Sequence; Biofilms; Cell Wall; Gastroenteritis; Gene Expression Regulation, Bacterial; Host Factor 1 Protein; Lipid A; Mannitol; Mass Spectrometry; Mice; Molecular Chaperones; Proteome; Proteomics; Regulatory Sequences, Ribonucleic Acid; RNA, Long Noncoding; RNA, Small Untranslated; Sequence Analysis, RNA; Sigma Factor; Transcription Factors; Yersinia enterocolitica; Yersinia Infections