2'-Fluoro-c-di-GMP as an oral vaccine adjuvant.

Bis-(3'-5')-cyclic dimeric 2'-deoxy-2'-fluoroguanosine monophosphate (2'-F-c-di-GMP) was synthesized through the modified H-phosphonate chemistry. Oral immunization of C57BL/6 mice with cell-free sonicate extract adjuvanted with 2'-F-c-di-GMP led to the production of antigen-specific antibodies in feces and sera, and lowered bacterial counts in the stomach upon post-vaccination infections in immunized mice. Similarly, oral vaccination of BALB/c mice with flagillin proteins from and adjuvanted with 2'-F-c-di-GMP led to production of antigen-specific antibodies both systemically and mucosally.

Acute intraperitoneal infection with a hypervirulent Acinetobacter baumannii isolate in mice.

Acinetobacter baumannii infection has become a major cause of healthcare-associated infection and a critical pathogen in the WHO antimicrobial resistance research and development priority list. Catheter-related septicemia is one of the major clinical manifestations of A. baumannii infection associated with high morbidity and mortality.

Mouse Models of Acinetobacter baumannii Infection.

This unit describes basic protocols for infecting mice through intranasal and intraperitoneal routes with Acinetobacter baumannii to induce associated pneumonia and sepsis, the two most common manifestations of clinical infections with this pathogen. By selecting the appropriate protocols and bacterial strains of different virulence, these mouse models provide an opportunity to study the infection pathogenesis and host-immune responses, and to evaluate the efficacies of prophylactic and therapeutic anti-A. baumannii candidates.

Host resistance to intranasal Acinetobacter baumannii reinfection in mice.

Acinetobacter baumannii is a major causative agent of healthcare-associated infection and develops multidrug resistance rapidly. However, little is known in the host defense mechanisms against this infection. In this study, we examined if mice recovered from a previous intranasal A.

Tolerance to cocaine in brain stimulation reward following continuous cocaine infusions.

This study examined tolerance to cocaine's threshold-lowering effect in brain stimulation reward (BSR) following continuous cocaine infusions and secondly, used the nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) to determine NO's involvement in the development of cocaine tolerance. Animals were continuously infused with saline or cocaine (30 mg/kg per day) via osmotic minipump for 14 days and injected daily with saline or L-NAME (30 mg/kg, i.p.

Intranasal immunization protects against Acinetobacter baumannii-associated pneumonia in mice.

Multidrug-resistant Acinetobacter baumannii has become an important causative agent of healthcare associated infections. Hospital- and community-acquired pneumonia is the most common clinical manifestation of A. baumannii infection worldwide and is often associated with high mortality.

Serum resistance, gallium nitrate tolerance and extrapulmonary dissemination are linked to heme consumption in a bacteremic strain of Acinetobacter baumannii.

Bacteremia caused by Acinetobacter baumannii is a highly lethal complication of hospital-acquired pneumonia. In the present study, we investigated the serum resistance, gallium nitrate tolerance and heme consumption of A. baumannii strain LAC-4 which was recently reported to display high virulence in a mouse pneumonia model with extrapulmonary dissemination leading to fatal bacteremia.

A mouse model of Acinetobacter baumannii-associated pneumonia using a clinically isolated hypervirulent strain.

Acinetobacter baumannii is an important emerging pathogen in health care-acquired infections and is responsible for severe nosocomial and community-acquired pneumonia. Currently available mouse models of A. baumannii pneumonia show poor colonization with little to no extrapulmonary dissemination.

Modulation of toxin production by the flagellar regulon in Clostridium difficile.

We show in this study that toxin production in Clostridium difficile is altered in cells which can no longer form flagellar filaments. The impact of inactivation of fliC, CD0240, fliF, fliG, fliM, and flhB-fliR flagellar genes upon toxin levels in culture supernatants was assessed using cell-based cytotoxicity assay, proteomics, immunoassay, and immunoblotting approaches. Each of these showed that toxin levels in supernatants were significantly increased in a fliC mutant compared to that in the C.

In vitro and in vivo biological activities of iron chelators and gallium nitrate against Acinetobacter baumannii.

We investigated the ability of compounds interfering with iron metabolism to inhibit the growth of Acinetobacter baumannii. Iron restriction with transferrin or 2,2-bipyridyl significantly inhibited A. baumannii growth in vitro.

Role of macrophages in early host resistance to respiratory Acinetobacter baumannii infection.

Acinetobacter baumannii is an emerging bacterial pathogen that causes nosocomial pneumonia and other infections. Although it is recognized as an increasing threat to immunocompromised patients, the mechanism of host defense against A. baumannii infection remains poorly understood.

Design and immunological properties of Helicobacter pylori glycoconjugates based on a truncated lipopolysaccharide lacking Lewis antigen and comprising an α-1,6-glucan chain.

To investigate the vaccine potential of H. pylori lipopolysaccharide (LPS), truncated LPS of H. pylori strain 26695 HP0826::Kan lacking O-chain polysaccharide and comprising an extended α-1,6-linked glucan chain was conjugated to tetanus toxoid (TT) or bovine serum albumin (BSA).

c-di-GMP protects against intranasal Acinetobacter baumannii infection in mice by chemokine induction and enhanced neutrophil recruitment.

Acinetobacter baumannii has emerged as a major cause of both community-associated and nosocomial infections worldwide. A. baumannii rapidly develops resistance to multiple antibiotics; as a result, infections by this pathogen have become increasingly difficult to treat.

Role of neutrophils and NADPH phagocyte oxidase in host defense against respiratory infection with virulent Francisella tularensis in mice.

Francisella tularensis subspecies (subsp.) tularensis is a CDC Category A biological warfare agent and inhalation of as few as 15 bacilli can initiate severe disease. Relatively little is known about the cellular and molecular mechanisms of host defense against respiratory infection with subsp.

Methylamidation for sialoglycomics by MALDI-MS: a facile derivatization strategy for both α2,3- and α2,6-linked sialic acids.

Neutralization of carboxylic acid is an important means to avoid sialic acid dissociation when sialylated glycans are analyzed by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). In this paper, we describe a simple and rapid method to modify the sialic acids of sialylated glycans in the presence of methylamine and (7-azabenzotriazol-1-yloxy) trispyrrolidinophosphonium hexafluorophosphate (PyAOP). After methylamidation, sialylated glycans can be analyzed by MALDI-MS without loss of the sialic acid moiety.

3',5'-Cyclic diguanylic acid elicits mucosal immunity against bacterial infection.

3',5'-Cyclic diguanylic acid (cdiGMP) is emerging as a universal bacterial second messenger in regulating bacterial growth on surfaces. It has been recently shown that cdiGMP stimulates innate immunity and enhances antigen-specific humoral and cellular immune responses. We herein report that intranasal (i.

High susceptibility to respiratory Acinetobacter baumannii infection in A/J mice is associated with a delay in early pulmonary recruitment of neutrophils.

Acinetobacter baumannii is an important cause of both community-associated and nosocomial pneumonia, which have become increasingly difficult to treat because of the rapid development of resistance to multiple antibiotics. Despite its clinical importance, the pathogenesis of and host defense against respiratory A. baumannii infection remains largely unknown.

Synthesis and immunostimulatory properties of the phosphorothioate analogues of cdiGMP.

The synthesis of mono- and bisphosphorothioate analogues of 3',5'-cyclic diguanylic acid (cdiGMP) via the modified H-phosphonate chemistry is reported. The immunostimulatory properties of these analogues were compared with those of cdiGMP.

Neutrophils play an important role in host resistance to respiratory infection with Acinetobacter baumannii in mice.

Acinetobacter baumannii has emerged as a major cause of both community-associated and nosocomial pneumonia, but little is known about the cellular and molecular mechanisms of host defense against respiratory infection with this bacterial pathogen. In this study, we examined the role of neutrophils in host resistance to pulmonary A. baumannii infection in a mouse model of intranasal (i.

Oral immunization of mice with the live vaccine strain (LVS) of Francisella tularensis protects mice against respiratory challenge with virulent type A F. tularensis.

Francisella tularensis is a Gram-negative intracellular bacterium, and the causative agent of tularemia. The infection can be initiated by various routes and can manifest itself in several clinical forms with the disseminated typhoidal form initiated by inhalation being most fatal. The attenuated live vaccine strain (LVS), developed almost 50 years ago, remains the sole effective tularemia vaccine, which is still only available as an investigational new drug for at-risk individuals.

Role of Toll-like receptors in health and diseases of gastrointestinal tract.

The human gastrointestinal (GI) tract is colonized by non-pathogenic commensal microflora and frequently exposed to many pathogenic organisms. For the maintenance of GI homeostasis, the host must discriminate between pathogenic and non-pathogenic organisms and initiate effective and appropriate immune and inflammatory responses. Mammalian toll-like receptors (TLRs) are members of the pattern-recognition receptor (PRR) family that plays a central role in the initiation of innate cellular immune responses and the subsequent adaptive immune responses to microbial pathogens.

Transcriptional profiling of host responses in mouse lungs following aerosol infection with type A Francisella tularensis.

Tularaemia caused by inhalation of type A Francisella tularensis bacteria is one of the most aggressive infectious diseases known, but the reasons for the very rapid spread of the organism from the lungs to internal organs and the ensuing mortality are unknown. The present study used the mouse model to examine in detail the host immune response in the lung. After an aerosol challenge with 20 c.

Archaeosomes as adjuvants for combination vaccines.

The present study evaluated the potential of archaesomes, prepared from the total polar lipids extracted from Methanobrevibacter smithii, as adjuvants for combination (multivalent) vaccines. Groups of Balb/c mice were immunized subcutaneously at day 0 and 21 with one of the following vaccines: trivalent vaccine formulated by the simultaneous co-encapsulation of bovine serum albumine (BSA), ovalbumin (OVA) and hen egg lysozyme (HEL) into archaeosomes (CEC vaccine); an univalent archaeosome vaccine (UVE vaccine) containing either BSA, OVA or HEL; or an admixture vaccine (AMC vaccine) consisting of the three UVE vaccines. Serum specific antibody (IgG + M) responses were determined at day 32, 112 and 203, and specific IgG1 and IgG2a responses were determined at day 112.

Toll-like receptor 4 (TLR4) does not confer a resistance advantage on mice against low-dose aerosol infection with virulent type A Francisella tularensis.

Francisella tularensis, the causative agent of tularemia, is a gram-negative facultative intracellular bacterium. Toll-like receptor (TLR) 4 is considered to be critical for inducing host innate immunity against many gram-negative bacteria including many respiratory pathogens. To determine the role of TLR4 in host defense against airborne F.

Susceptibility of immunodeficient mice to aerosol and systemic infection with virulent strains of Francisella tularensis.

Previous studies have shown that IFN-gamma, TNF-alpha and NOS-2, but not B cells, are crucial for host defense against primary systemic infection with the attenuated live vaccine strain (LVS) of Francisella tularensis. In this study, we examined the importance of these and additional immune components in host resistance against infection with virulent strains of F. tularensis initiated by systemic and airborne routes.