Mucosal Immune Profiles Associated with Diarrheal Disease Severity in - and Enteropathogenic Escherichia coli-Infected Children Enrolled in the Global Enteric Multicenter Study.

Enteropathogenic Escherichia coli (EPEC) and are etiologic agents of diarrhea in children <5 years old living in resource-poor countries. Repeated bouts of infection lead to lifelong morbidity and even death. The goal of this study was to characterize local mucosal immune responses in - and EPEC-infected children <5 years of age with moderate to severe diarrhea (MSD) enrolled in the Global Enteric Multicenter Study (GEMS).

Tick extracellular vesicles enable arthropod feeding and promote distinct outcomes of bacterial infection.

Extracellular vesicles are thought to facilitate pathogen transmission from arthropods to humans and other animals. Here, we reveal that pathogen spreading from arthropods to the mammalian host is multifaceted. Extracellular vesicles from Ixodes scapularis enable tick feeding and promote infection of the mildly virulent rickettsial agent Anaplasma phagocytophilum through the SNARE proteins Vamp33 and Synaptobrevin 2 and dendritic epidermal T cells.

Strategies for Enhancement of Live-Attenuated -Based Carrier Vaccine Immunogenicity.

The use of live-attenuated bacterial vaccines as carriers for the mucosal delivery of foreign antigens to stimulate the mucosal immune system was first proposed over three decades ago. This novel strategy aimed to induce immunity against at least two distinct pathogens using a single bivalent carrier vaccine. It was first tested using a live-attenuated serovar Typhi strain in clinical trials in 1984, with excellent humoral immune responses against the carrier strain but only modest responses elicited against the foreign antigen.

A Phase 1 dose escalating study of double mutant heat-labile toxin LTR192G/L211A (dmLT) from Enterotoxigenic Escherichia coli (ETEC) by sublingual or oral immunization.

Background: The public health burden of Enterotoxigenic Escherichia coli (ETEC) is high but no vaccine is specifically approved to prevent ETEC infections.

Methods: We performed a Phase 1, dose escalation study (1-50 µg) evaluating the sublingual (SL) delivery of the double mutant heat-labile toxin LTR192G/L211A (dmLT) in 80 healthy adult volunteers. The primary objective was safety and the secondary was the immunogenicity of the dmLT.

Functional and Antigen-Specific Serum Antibody Levels as Correlates of Protection against Shigellosis in a Controlled Human Challenge Study.

Shigella is an important cause of diarrheal disease in young children living in developing countries. No approved vaccines are available, and the development of vaccine candidates has been hindered by the lack of firm immunological correlates of protection, among other reasons. To address this gap in knowledge, we established quantitative assays to measure Shigella-specific serum bactericidal antibody (SBA) and opsonophagocytic killing antibody (OPKA) activities and investigated their potential association with protection against disease in humans.

Live Attenuated Human Salmonella Vaccine Candidates: Tracking the Pathogen in Natural Infection and Stimulation of Host Immunity.

Salmonellosis, caused by members of the genus Salmonella, is responsible for considerable global morbidity and mortality in both animals and humans. In this review, we will discuss the pathogenesis of Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium, focusing on human Salmonella infections. We will trace the path of Salmonella through the body, including host entry sites, tissues and organs affected, and mechanisms involved in both pathogenesis and stimulation of host immunity.

A murine inhalation model to characterize pulmonary exposure to dry Aspergillus fumigatus conidia.

Most murine models of fungal exposure are based on the delivery of uncharacterized extracts or liquid conidia suspensions using aspiration or intranasal approaches. Studies that model exposure to dry fungal aerosols using whole body inhalation have only recently been described. In this study, we aimed to characterize pulmonary immune responses following repeated inhalation of conidia utilizing an acoustical generator to deliver dry fungal aerosols to mice housed in a nose only exposure chamber.

A bivalent typhoid live vector vaccine expressing both chromosome- and plasmid-encoded Yersinia pestis antigens fully protects against murine lethal pulmonary plague infection.

Live attenuated bacteria hold great promise as multivalent mucosal vaccines against a variety of pathogens. A major challenge of this approach has been the successful delivery of sufficient amounts of vaccine antigens to adequately prime the immune system without overattenuating the live vaccine. Here we used a live attenuated Salmonella enterica serovar Typhi strain to create a bivalent mucosal plague vaccine that produces both the protective F1 capsular antigen of Yersinia pestis and the LcrV protein required for secretion of virulence effector proteins.

Pulmonary immune responses to Aspergillus fumigatus in an immunocompetent mouse model of repeated exposures.

Aspergillus fumigatus is a filamentous fungus that produces abundant pigmented conidia. Several fungal components have been identified as virulence factors, including melanin; however, the impact of these factors in a repeated exposure model resembling natural environmental exposures remains unknown. This study examined the role of fungal melanin in the stimulation of pulmonary immune responses using immunocompetent BALB/c mice in a multiple exposure model.

Role of germination in murine airway CD8+ T-cell responses to Aspergillus conidia.

Pulmonary exposure to Aspergillus fumigatus has been associated with morbidity and mortality, particularly in immunocompromised individuals. A. fumigatus conidia produce β-glucan, proteases, and other immunostimulatory factors upon germination.

Fungal pigments inhibit the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of darkly pigmented fungi.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used to discriminate moniliaceous fungal species; however, darkly pigmented fungi yield poor fingerprint mass spectra that contain few peaks of low relative abundance. In this study, the effect of dark fungal pigments on the observed MALDI mass spectra was investigated. Peptide and protein samples containing varying concentrations of synthetic melanin or fungal pigments extracted from Aspergillus niger were analyzed by MALDI-TOF and MALDI-qTOF (quadrupole TOF) MS.

Murine models of airway fungal exposure and allergic sensitization.

Inhalation of common indoor filamentous fungi has been associated with the induction or exacerbation of allergic respiratory disease. The understanding of fungal inhalation and allergic sensitization has significantly advanced with the use of small animal models, especially mouse models. Numerous studies have employed different animal exposure and sensitization techniques, each with inherent advantages and disadvantages that are addressed in this review.

Discrimination of Penicillium isolates by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to generate highly reproducible mass spectral 'fingerprints' for twelve Penicillium species. Prior to MALDI-TOF MS analysis, eight replicate cultures of each Penicillium species were subjected to three one-minute bead-beating cycles in an acetonitrile/trifluoroacetic acid solvent. The mass spectra contained abundant peaks in the range of m/z 5000-20 000, and allowed unambiguous discrimination between species.

Discrimination of Aspergillus isolates at the species and strain level by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry fingerprinting.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used to generate highly reproducible mass spectral fingerprints for 12 species of fungi of the genus Aspergillus and 5 different strains of Aspergillus flavus. Prior to MALDI-TOF MS analysis, the fungi were subjected to three 1-min bead beating cycles in an acetonitrile/trifluoroacetic acid solvent. The mass spectra contain abundant peaks in the range of 5 to 20kDa and may be used to discriminate between species unambiguously.