Immunogenicity and safety of BPZE1, an intranasal live attenuated pertussis vaccine, versus tetanus-diphtheria-acellular pertussis vaccine: a randomised, double-blind, phase 2b trial.

Background: Bordetella pertussis epidemics persist as transmission remains unabated despite high acellular pertussis vaccination rates. BPZE1, a live attenuated intranasal pertussis vaccine, was designed to prevent B pertussis infection and disease. We aimed to assess the immunogenicity and safety of BPZE1 compared with the tetanus-diphtheria-acellular pertussis vaccine (Tdap).

Sequence-dependent inhibition of cGAS and TLR9 DNA sensing by 2'-O-methyl gapmer oligonucleotides.

Oligonucleotide-based therapeutics have the capacity to engage with nucleic acid immune sensors to activate or block their response, but a detailed understanding of these immunomodulatory effects is currently lacking. We recently showed that 2'-O-methyl (2'OMe) gapmer antisense oligonucleotides (ASOs) exhibited sequence-dependent inhibition of sensing by the RNA sensor Toll-Like Receptor (TLR) 7. Here we discovered that 2'OMe ASOs can also display sequence-dependent inhibitory effects on two major sensors of DNA, namely cyclic GMP-AMP synthase (cGAS) and TLR9.

Innate Immune Molecule NLRC5 Protects Mice From Helicobacter-induced Formation of Gastric Lymphoid Tissue.

Background & Aims: Helicobacter pylori induces strong inflammatory responses that are directed at clearing the infection, but if not controlled, these responses can be harmful to the host. We investigated the immune-regulatory effects of the innate immune molecule, nucleotide-binding oligomerization domain-like receptors (NLR) family CARD domain-containing 5 (NLRC5), in patients and mice with Helicobacter infection.

Methods: We obtained gastric biopsies from 30 patients in Australia.

The Use of CRISPR/Cas9 Gene Editing to Confirm Congenic Contaminations in Host-Pathogen Interaction Studies.

Murine models of serovar Typhimurium infection are one of the commonest tools to study host-pathogen interactions during bacterial infections. Critically, the outcome of . Typhimurium infection is impacted by the genetic background of the mouse strain used, with macrophages from C57BL/6 and BALB/c mice lacking the capacity to control intracellular bacterial replication.

Topoisomerase 1 Inhibition Promotes Cyclic GMP-AMP Synthase-Dependent Antiviral Responses.

Inflammatory responses, while essential for pathogen clearance, can also be deleterious to the host. Chemical inhibition of topoisomerase 1 (Top1) by low-dose camptothecin (CPT) can suppress transcriptional induction of antiviral and inflammatory genes and protect animals from excessive and damaging inflammatory responses. We describe the unexpected finding that minor DNA damage from topoisomerase 1 inhibition with low-dose CPT can trigger a strong antiviral immune response through cyclic GMP-AMP synthase (cGAS) detection of cytoplasmic DNA.

Assessing the Off-Target Effects of miRNA Inhibitors on Innate Immune Toll-Like Receptors.

MicroRNAs (miRNAs) are involved in most cellular processes and are deregulated in several diseases. Antisense miRNA oligonucleotides (AMOs) therefore present novel therapeutic opportunities. Currently, in vivo delivery of AMOs often relies on high doses of nucleic acids, with nonspecific uptake by most tissues.

Activation of cGAS-dependent antiviral responses by DNA intercalating agents.

Acridine dyes, including proflavine and acriflavine, were commonly used as antiseptics before the advent of penicillins in the mid-1940s. While their mode of action on pathogens was originally attributed to their DNA intercalating activity, work in the early 1970s suggested involvement of the host immune responses, characterized by induction of interferon (IFN)-like activities through an unknown mechanism. We demonstrate here that sub-toxic concentrations of a mixture of acriflavine and proflavine instigate a cyclic-GMP-AMP (cGAMP) synthase (cGAS)-dependent type-I IFN antiviral response.

Cre-dependent DNA recombination activates a STING-dependent innate immune response.

Gene-recombinase technologies, such as Cre/loxP-mediated DNA recombination, are important tools in the study of gene function, but have potential side effects due to damaging activity on DNA. Here we show that DNA recombination by Cre instigates a robust antiviral response in mammalian cells, independent of legitimate loxP recombination. This is due to the recruitment of the cytosolic DNA sensor STING, concurrent with Cre-dependent DNA damage and the accumulation of cytoplasmic DNA.

Assessing the Inhibitory Activity of Oligonucleotides on TLR7 Sensing.

Aberrant sensing of self-nucleic acids by Toll-like receptor (TLR) 7, 8, or 9 is associated with several autoimmune disorders, including systemic lupus erythematosus (SLE), rheumatoid arthritis, psoriasis, or systemic sclerosis. In recent years, several classes of synthetic oligonucleotides have been shown to antagonize sensing of immunostimulatory nucleic acids by TLR7/8/9, indicating that these molecules could have therapeutic applications in such autoimmune diseases. Conversely, synthetic oligonucleotides used in therapeutic technologies such as antisense and microRNA inhibitors also have the potential to inhibit TLR7/8/9 sensing, rendering patients more susceptible to viral/bacterial infections.

Sequence-dependent off-target inhibition of TLR7/8 sensing by synthetic microRNA inhibitors.

Anti-microRNA (miRNA) oligonucleotides (AMOs) with 2'-O-Methyl (2'OMe) residues are commonly used to study miRNA function and can achieve high potency, with low cytotoxicity. Not withstanding this, we demonstrate the sequence-dependent capacity of 2'OMe AMOs to inhibit Toll-like receptor (TLR) 7 and 8 sensing of immunostimulatory RNA, independent of their miRNA-targeting function. Through a screen of 29 AMOs targeting common miRNAs, we found a subset of sequences highly inhibitory to TLR7 sensing in mouse macrophages.

Recognition of Extracellular Bacteria by NLRs and Its Role in the Development of Adaptive Immunity.

Innate immune recognition of bacteria is the first requirement for mounting an effective immune response able to control infection. Over the previous decade, the general paradigm was that extracellular bacteria were only sensed by cell surface-expressed Toll-like receptors (TLRs), whereas cytoplasmic sensors, including members of the Nod-like receptor (NLR) family, were specific to pathogens capable of breaching the host cell membrane. It has become apparent, however, that intracellular innate immune molecules, such as the NLRs, play key roles in the sensing of not only intracellular, but also extracellular bacterial pathogens or their components.

Nucleotide oligomerization domain 1 enhances IFN-γ signaling in gastric epithelial cells during Helicobacter pylori infection and exacerbates disease severity.

Virulent Helicobacter pylori strains that specifically activate signaling in epithelial cells via the innate immune molecule, nucleotide oligomerization domain 1 (NOD1), are more frequently associated with IFN-γ-dependent inflammation and with severe clinical outcomes (i.e., gastric cancer and peptic ulceration).

Helicobacter pylori infection of gastrointestinal epithelial cells in vitro induces mesenchymal stem cell migration through an NF-κB-dependent pathway.

The role of bone marrow-derived mesenchymal stem cells (MSC) in the physiology of the gastrointestinal tract epithelium is currently not well established. These cells can be recruited in response to inflammation due to epithelial damage, home, and participate in tissue repair. In addition, in the case of tissue repair failure, these cells could transform and be at the origin of carcinomas.

Helicobacter pylori infection recruits bone marrow-derived cells that participate in gastric preneoplasia in mice.

Background & Aims: Studies in animal models have shown that bone marrow-derived cells (BMDC) could be involved in the formation of carcinomas of the upper gastrointestinal tract, including gastric carcinoma. Most gastric carcinomas in humans have been associated with chronic infection with Helicobacter pylori; we investigated the bacteria's potential to induce premalignant lesions in mice and studied the kinetics of BMDC settlement in the gastric epithelium.

Methods: C57BL/6J female chimeric mice with BMDCs from male donors that express green fluorescent protein were infected with human-derived and mouse-adapted strains of H pylori and followed.

Human bone marrow-derived stem cells acquire epithelial characteristics through fusion with gastrointestinal epithelial cells.

Bone marrow-derived mesenchymal stem cells (MSC) have the ability to differentiate into a variety of cell types and are a potential source for epithelial tissue repair. Several studies have demonstrated their ability to repopulate the gastrointestinal tract (GIT) in bone marrow transplanted patients or in animal models of gastrointestinal carcinogenesis where they were the source of epithelial cancers. However, mechanism of MSC epithelial differentiation still remains unclear and controversial with trans-differentiation or fusion events being evoked.

Evaluation of the clinical significance of homB, a novel candidate marker of Helicobacter pylori strains associated with peptic ulcer disease.

Background: homB codes for a putative Helicobacter pylori outer membrane protein and has previously been associated with peptic ulcer disease (PUD) in children.

Methods: A total of 190 H. pylori strains isolated from children and adults were studied to evaluate the clinical importance of the homB gene.

Modulation of lymphocyte proliferation induced by gastric MALT lymphoma-associated Helicobacter pylori strains.

Background: Helicobacter pylori infection leads to different chronic diseases, suggesting that this bacterium can evade the host immune defense system. The ability to control lymphocyte proliferation may be a mechanism leading to the development of gastric pathologies. Our aim was to characterize the effects of mucosa-associated lymphoid tissue (MALT) associated H.