Anti-Toxin Responses to Natural Enterotoxigenic (ETEC) Infection in Adults and Children in Bangladesh.

A sero-epidemiology study was conducted in Dhaka, Bangladesh between January 2020 and February 2021 to assess the immune responses to ETEC infection in adults and children. (1) Background: Enterotoxigenic infection is a main cause of diarrheal disease in endemic countries. The characterization of the immune responses evoked by natural infection can guide vaccine development efforts.

Evaluation of the Safety, Tolerability and Immunogenicity of ShigETEC, an Oral Live Attenuated -ETEC Vaccine in Placebo-Controlled Randomized Phase 1 Trial.

Background: spp. and enterotoxigenic (ETEC) cause high morbidity and mortality worldwide, yet no licensed vaccines are available to prevent corresponding infections. A live attenuated non-invasive vaccine strain lacking LPS O-antigen and expressing the ETEC toxoids, named ShigETEC was characterized previously in non-clinical studies.

Characterization of ShigETEC, a Novel Live Attenuated Combined Vaccine against Shigellae and ETEC.

: spp. and enterotoxigenic (ETEC) remain the two leading bacterial causes of diarrheal diseases worldwide. Attempts to develop preventive vaccines against Shigella and ETEC have not yet been successful.

Cationic amphipathic peptides accumulate sialylated proteins and lipids in the plasma membrane of eukaryotic host cells.

Cationic antimicrobial peptides (CAMPs) selectively target bacterial membranes by electrostatic interactions with negatively charged lipids. It turned out that for inhibition of microbial growth a high CAMP membrane concentration is required, which can be realized by the incorporation of hydrophobic groups within the peptide. Increasing hydrophobicity, however, reduces the CAMP selectivity for bacterial over eukaryotic host membranes, thereby causing the risk of detrimental side-effects.

Adjuvating the adjuvant: facilitated delivery of an immunomodulatory oligonucleotide to TLR9 by a cationic antimicrobial peptide in dendritic cells.

IC31(®) is a novel bi-component vaccine adjuvant consisting of the peptide KLKL(5)KLK (KLK) and the TLR9 agonist oligonucleotide d(IC)(13) (ODN1a). While membrane-interacting properties of KLK and immuno-modulating capabilities of ODN1a have been characterized in detail, little is known of how these two molecules function together and synergize in interacting with their primary target cells, dendritic cells (DCs). We have found that KLK-triggered aggregates entrapped ODN1a and these complexes readily associated with the DC cell surface.

Immunological fingerprinting of group B streptococci: from circulating human antibodies to protective antigens.

Group B streptococcus is one of the most important pathogens in neonates, and causes invasive infections in non-pregnant adults with underlying diseases. Applying a genomic approach that relies on human antibodies we identified antigenic GBS proteins, among them most of the previously published protective antigens. In vitro analyses allowed the selection of conserved candidate antigens that were further evaluated in murine lethal sepsis models using several GBS strains.

Antimicrobial and immunostimulatory peptide, KLK, induces an increase in cytosolic Ca²(+) concentration by mobilizing Ca²(+) from intracellular stores.

The cationic antimicrobial immunomodulatory peptide, KLK (KLKL₅KLK), exerts profound membrane interacting properties, impacting on ultrastructure and fluidity. KLK-membrane interactions that lead to these alterations require the ability of the peptide to move into an α-helical conformation. We show that KLK induces an increase of the intracellular Ca²(+) concentration in human T24 cells.

Novel conserved group A streptococcal proteins identified by the antigenome technology as vaccine candidates for a non-M protein-based vaccine.

Group A streptococci (GAS) can cause a wide variety of human infections ranging from asymptomatic colonization to life-threatening invasive diseases. Although antibiotic treatment is very effective, when left untreated, Streptococcus pyogenes infections can lead to poststreptococcal sequelae and severe disease causing significant morbidity and mortality worldwide. To aid the development of a non-M protein-based prophylactic vaccine for the prevention of group A streptococcal infections, we identified novel immunogenic proteins using genomic surface display libraries and human serum antibodies from donors exposed to or infected by S.

Composition of the ANTIGENome of Helicobacter pylori defined by human serum antibodies.

Helicobacter pylori is the most prevalent human pathogen and although, it remains silent in most individuals for lifetime, colonization may develop into severe gastric and duodenal conditions. Rapidly developing resistance to antibiotic treatment urgently calls for the development of effective vaccines. We determined the ANTIGENome of two clinical isolates of H.

Unique membrane-interacting properties of the immunostimulatory cationic peptide KLKL(5)KLK (KLK).

We have monitored the effects of KLKL(5)KLK (KLK), a derivative of a natural cationic antimicrobial peptide (CAP) on isolated membrane vesicles, and investigated the partition of the peptide within these structures. KLK readily interacted with fluorescent dyes entrapped in the vesicles without apparent pore formation. Fractionation of vesicles revealed KLK predominantly in the membrane.

Discovery of a novel class of highly conserved vaccine antigens using genomic scale antigenic fingerprinting of pneumococcus with human antibodies.

Pneumococcus is one of the most important human pathogens that causes life-threatening invasive diseases, especially at the extremities of age. Capsular polysaccharides (CPSs) are known to induce protective antibodies; however, it is not feasible to develop CPS-based vaccines that cover all of the 90 disease-causing serotypes. We applied a genomic approach and described the antibody repertoire for pneumococcal proteins using display libraries expressing 15-150 amino acid fragments of the pathogen's proteome.

RNA delivery by heat shock protein-70 into mammalian cells: a preliminary study.

Heat shock proteins (Hsps) are ubiquitous molecular chaperones with indispensable roles in assisting protein folding and giving protection from proteotoxic environmental harm. Members of the 70-kDa heat shock protein family have been demonstrated to recognize and bind with distinguished RNA sequences, which function as determinants of eukaryotic mRNA stability. We have earlier identified the molecular domains involved in RNA-binding and characterized in detail the specificity, affinity and some regulatory aspects of this molecular interaction using various deletion mutants and homologues of Hsp70.

[Antigenome technology: rapid and comprehensive identification and validation of antigens as putative components in vaccines against bacterial pathogens].

The resolution of complete genome sequences of many pathogens has dramatically expanded our perspectives in developing novel vaccines by increasing both the speed and scale of target identification. Genomics-based technologies with their significant advantages can be applied to most pathogens and have exploited genome sequence information in alliance with adjunct technologies, including bioinformatics, expression analyses (microarrays, in vivo expression technologies), random mutagenesis or protein/peptide based selection methods (proteomics and immunoselection using expression libraries). A novel approach that combines the advantages of full genome coverage and serological antigen identification has been developed in the laboratory of the authors for the identification of protein antigens from bacterial pathogens.

Antigenome technology: a novel approach for the selection of bacterial vaccine candidate antigens.

A novel approach for the identification of protein antigens from bacterial pathogens was previously developed in our laboratory that combines the advantages of full genome coverage and serological antigen identification. We have applied this technology to several bacterial pathogens of the genera Staphylococcus and Streptococcus and have, as a result, defined the "antigenome" of these pathogens. This catalogue defines the most relevant antigenic proteins that are targeted by the human immune system, including their antibody binding sites.

Comparison of antibody repertoires against Staphylococcus aureus in healthy individuals and in acutely infected patients.

The management of staphylococcal diseases is increasingly difficult with present medical approaches. Preventive and therapeutic vaccination is considered to be a promising alternative; however, little is known about immune correlates of protection and disease susceptibility. To better understand the immune recognition of Staphylococcus aureus by the human host, we studied the antistaphylococcal humoral responses in healthy people in comparison to those of patients with invasive diseases.

Bacterial genomes pave the way to novel vaccines.

The availability of complete genome sequences of pathogens has dramatically changed the scope for developing improved and novel vaccines by increasing the speed of target identification. Genomics-based technologies have many advantages, compared to conventional approaches, which are time-consuming and usually identify only abundant antigens that are expressible under in vitro culture conditions. This review focuses on recent reports of genomics-based strategies that can be applied to most pathogens and that exploit genome sequence information in alliance with adjunct technologies, including bioinformatics, expression analyses, random mutagenesis or protein/peptide-based selection methods.

Functional selection of vaccine candidate peptides from Staphylococcus aureus whole-genome expression libraries in vitro.

An in vitro protein selection method, ribosome display, has been applied to comprehensively identify and map the immunologically relevant proteins of the human pathogen Staphylococcus aureus. A library built up from genomic fragments of the virulent S. aureus COL strain (methicillin-resistant S.

Extending the 'stressy' edge: molecular chaperones flirting with RNA.

A number of intriguing observations have emerged during the past years indicating that certain classes of the evolutionarily highly conserved heat shock or stress proteins extend their molecular partnerships beyond the originally recognized protein world. In this review, following a brief introduction to the 70-kDa family of stress proteins, we summarize the main aspects of RNA recognition and binding by this class of molecules. By highlighting some biochemical features of both the protein and RNA partners, we attempt to embed the central parts of this interaction in the context of potential physiological relevance.

Surface binding and uptake of heat shock protein 70 by antigen-presenting cells require all 3 domains of the molecule.

The surprisingly efficient uptake of peptide-loaded heat shock proteins (Hsps) by antigen-presenting cells (APCs) has been recently associated with a specific receptor-ligand-based mechanism, and the identity of at least 1 receptor has been determined. In this study, we tested how the domain composition of the stress protein affected its surface association and internalization by APCs, and this was facilitated by the availability of the 70-kDa human heat shock protein (Hsp70) and its various deletion mutants. We show that both these processes strictly depend on the presence of all 3 domains of Hsp70.

Identification of in vivo expressed vaccine candidate antigens from Staphylococcus aureus.

For the design of potent subunit vaccines, it is of paramount importance to identify all antigens immunologically recognized by a patient population infected with a pathogen. We have developed a rapid and efficient procedure to identify such commonly recognized antigens, and here we provide a comprehensive in vivo antigenic profile of Staphylococcus aureus, an important human pathogen. S.