bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison ofEscherichia coliStrains Recovered from Human Cystitis and Pyelonephritis Infections in Transurethrally Challenged Mice
Authors: Johnson David E. , Lockatell C. Virginia , Russell Robert G. , Hebel J. Richard , Island Michael D. , Stapleton Ann , Stamm Walter E. , Warren John W. 
Published: December 2019

ABSTRACTUrinary tract infection, most frequently caused byEscherichia coli, is one of the most common bacterial infections in humans. A vast amount of literature regarding the mechanisms through whichE. coliinduces pyelonephritis has accumulated. Although cystitis accounts for 95% of visits to physicians for symptoms of urinary tract infections, few in vivo studies have investigated possible differences betweenE. colirecovered from patients with clinical symptoms of cystitis and that from patients with symptoms of pyelonephritis. Epidemiological studies indicate that cystitis-associated strains appear to differ from pyelonephritis-associated strains in elaboration of some putative virulence factors. With transurethrally challenged mice we studied possible differences using three each of the most virulent pyelonephritis and cystitisE. colistrains in our collection. The results indicate that cystitis strains colonize the bladder more rapidly than do pyelonephritis strains, while the rates of kidney colonization are similar. Cystitis strains colonize the bladder in higher numbers, induce more pronounced histologic changes in the bladder, and are more rapidly eliminated from the mouse urinary tract than pyelonephritis strains. These results provide evidence that cystitis strains differ from pyelonephritis strains in this model, that this model is useful for the study of the uropathogenicity of cystitis strains, and that it would be unwise to use pyelonephritis strains to study putative virulence factors important in the development of cystitis.
Oral Vaccination against Tetanus: Comparison of the Immunogenicities ofSalmonellaStrains Expressing Fragment C from thenirBandhtrAPromoters
Authors: Roberts Mark , Li Jingli , Bacon Andrew , Chatfield Steven 
Published: December 2019

ABSTRACTWe have found the in vivo-regulatednirBpromoter (PnirB) to be effective for directing expression of a number of antigens in salmonella in vivo. We wished to determine if other in vivo-regulated promoters have utility for antigen expression in salmonella and to compare the effectiveness of these promoters with that of PnirB. To this end, we have devised a scheme that allows the promoter element of the PnirB-fragment C plasmid pTETnir15 to be swapped with other promoters of interest. We demonstrate the usefulness of this system by replacing PnirBwith PhtrAto create plasmid pTEThtrA1.htrAis a stress response gene that is required for virulence of salmonella in mice and survival within macrophages. Expression of fragment C inSalmonella typhimuriumBRD509 (aroA aroD) harboring pTEThtrA1 (strain BRD937) correlated with growth temperature in vitro. A comparison was made of the immune responses to fragment C elicited in mice immunized orally with BRD937 or BRD847 (BRD509/pTETnir15) or subcutaneously with purified fragment C plus alhydrogel. High levels of anti-fragment C antibodies that persisted for at least 12 weeks were present in all groups of mice. Vaccination with BRD937 was the most effective means of immunization: the serum immunoglobulin G (IgG), IgA, and IgM anti-fragment C titers were higher in the BRD937-immunized mice throughout the duration of the study than in mice in the other groups. The kinetics of the serum anti-fragment C responses were different in different groups. The response was most rapid in the BRD937 group, with the titers almost at peak levels at 2 weeks postimmunization. Only the mice immunized with BRD937 or BRD847 developed an intestinal IgA response to fragment C. Again, the response was superior in the BRD937 group. The peak of the intestinal response was delayed with respect to the serum response. Analysis of the IgG subtype response to fragment C revealed a dominant IgG2a response in the salmonella-immunized mice, indicating a type 1 helper T-cell response to fragment C, whereas the major subtype in the group parenterally immunized with fragment C plus alhydrogel was IgG1. The IgG1/IgG2a ratio was much higher in sera of BRD937-immunized mice than in sera of BRD847-immunized mice. At 15 to 20 weeks after immunization, the mice immunized with BRD937 or BRD847 were solidly immune to tetanus toxin and salmonella. The immune responses to fragment C seen in mice immunized with BRD937 are the strongest we have observed and indicate that thehtrApromoter may be very useful for expressing foreign antigens in salmonella vaccine strains.
Inhibition of Murine Splenic and Mucosal Lymphocyte Function by Enteric Bacterial Products
Authors: Malstrom Carolyn , James Stephen 
Published: December 2019

ABSTRACTPreviously we showed that lysates of enteropathogenicEscherichia coli(EPEC) inhibit lymphokine production by mitogen-activated human peripheral blood and lamina propria mononuclear cells. The aims of the present study were to determine whether EPEC-inhibitory factors have similar effects on murine lymphoid populations in order to further delineate the mechanisms of alteration of cytokine production. Preexposure to EPEC lysates inhibited mitogen-stimulated interleukin-2 (IL-2), IL-4, and gamma interferon (IFN-γ) production by murine spleen cells, but IL-10 production was increased. The inhibition was not due to increased apoptosis and was not blocked by neutralizating antibodies against IL-10 or transforming growth factor β (TGF-β). EPEC lysates also inhibited mitogen-stimulated IL-2 and IFN-γ production by CD11b-depleted spleen cells, IL-2 and IL-4 production by intraepithelial and Peyer’s patch lymphocytes, IL-2 production by the human T-cell line Jurkat, and antigen-stimulated IL-2 production by murine spleen cells. Lysates obtained from Shiga-like toxin-producingE. coli,E. coliRDEC-1,Citrobacter rodentium, and an EPECespBinsertion mutant all inhibited IL-2 and IL-4 production by mitogen-stimulated lymphoid cells. In conclusion, lysates of EPEC and related bacteria directly inhibit cytokine production by lymphoid cells from multiple sites by a mechanism that does not increase apoptosis or result from secondary effects of IL-10 or TGF-β.
In Vitro Effects of a High-Molecular-Weight Heat-Labile Enterotoxin from Enteroaggregative
Escherichia coli
Authors: Navarro-García Fernando , Eslava Carlos , Villaseca Jorge M. , López-Revilla Rubén , Czeczulin John R. , Srinivas S. , Nataro James P. , Cravioto Alejandro 
Published: December 2019

ABSTRACT

The pathogenic mechanisms of enteroaggregative
Escherichia coli
(EAggEC) infection are not fully elucidated. In this work we show that an ammonium sulfate precipitate of culture supernatant of EAggEC strain 049766 increased the potential difference (PD) and the short-circuit current (Isc) in rat jejunal preparations mounted in Ussing chambers. The precipitate contained two major proteins of 108 and 116 kDa, which were partially copurified by chromatography in DEAE-cellulose. This chromatographic fraction (peak I) increased jejunal PD and Isc in a dose-dependent manner, accompanied by a decrease in tissue electrical resistance. These effects were inhibited by incubation of peak I at 75°C for 15 min or for 1 h with proteinase K at 37°C. Rabbit polyclonal antibodies against peak I containing both the 108- and 116-kDa proteins inhibited the enterotoxic effect. Specific polyclonal antibodies raised against the 108-kDa but not against the 116-kDa protein inhibited the enterotoxic effect, suggesting that the 108-kDa protein is the active toxic species. Moreover, another EAggEC strain (065126) producing the 116-kDa protein but not the 108-kDa protein had no effect on rat jejunal mucosa in the Ussing chamber. The >100-kDa fraction derived from prototype EAggEC strain 042, which also expressed both 108- and 116-kDa proteins, also produced an enterotoxic effect on rat jejunal preparations in Ussing chambers; however, the same strain cured of its 65-MDa adherence plasmid did not. A subclone derived from the 65-MDa plasmid expressing the 108-kDa toxin (and not the 116-kDa protein) elicited rises in Isc. Tissue exposed to any preparation containing the 108-kDa toxin exhibited similar histopathologic changes, characterized by increased mucus release, exfoliation of cells, and development of crypt abscesses. Our data suggest that some EAggEC strains produce a ca. 108-kDa enterotoxin/cytotoxin which is encoded on the large virulence plasmid.
Mucosal Delivery of Murine Interleukin-2 (IL-2) and IL-6 by Recombinant Strains ofLactococcus lactisCoexpressing Antigen and Cytokine
Authors: Steidler Lothar , Robinson Karen , Chamberlain Lisa , Schofield Karin M. , Remaut Erik , Le Page Richard W. F. , Wells Jeremy M. 
Published: December 2019

ABSTRACTLactococcus lactisis a nonpathogenic and noncolonizing bacterium which is being developed as a vaccine delivery vehicle for immunization by mucosal routes. To determine whether lactococci can also deliver cytokines to the immune system, we have constructed novel constitutive expression strains ofL. lactiswhich accumulate a test antigen, tetanus toxin fragment C (TTFC), within the cytoplasmic compartment and also secrete either murine interleukin-2 (IL-2) or IL-6. When mice were immunized intranasally with various different expression strains ofL. lactis, the anti-TTFC antibody titers increased more rapidly and were substantially higher in mice immunized with the bacterial strains which secreted IL-2 or IL-6 in addition to their production of TTFC. This adjuvant effect was lost when the recombinant strains ofL. lactiswere killed by pretreatment with mitomycin C and could therefore be attributed to the secretion of IL-2 or IL-6 by the recombinant lactococci. These results provide the first example of the use of a cytokine-secreting, noninvasive experimental bacterial vaccine vector to enhance immune responses to a coexpressed heterologous antigen and point the way to experiments which will test the possible therapeutic efficacy of this mode of cytokine delivery.
Bioluminescence as a Reporter of Intracellular Survival of
Bordetella bronchiseptica
in Murine Phagocytes
Authors: Forde Catrina B. , Parton Roger , Coote John G. 
Published: December 2019

ABSTRACT

The uptake and persistence of
Bordetella bronchiseptica
was characterized in murine phagocytes by using a novel bioluminescence-based reporter system. A mini-Tn
5
promoter probe carrying the intact
lux
operon from the terrestrial bacterium
Photorhabdus luminescens
which allowed measurement of light output without the addition of exogenous substrate was constructed. It was used to create a pool of bioluminescent fusion strains of
B. bronchiseptica
. The internalization and persistence in murine macrophages of a constitutive bioluminescent strain of
B. bronchiseptica
was monitored by luminometry and by fluorescence and electron microscopy. The number of bacteria internalized, in a microfilament-dependent process, by a mouse macrophage-like cell line after 2 h was approximately 1% of the inoculum for several different multiplicities of infection (MOI). At an MOI of <500:1 (bacteria to macrophages), viable numbers of intracellular bacteria declined over a 4-day period. However, at an MOI of ≥500:1, long-term survival was enhanced, with viable bacteria recovered up to 4 days postinfection with little decline in numbers, indicating that a critical population size may have been essential for intracellular persistence. No evidence of macrophage killing by intracellular bacteria was detected over the 4-day period. Intracellular bioluminescent
B. bronchiseptica
organisms in mouse peritoneal cells were detected at 24 and 48 h after intraperitoneal injection of mice. Bioluminescence is shown to act as a convenient real-time technique for monitoring of intracellular survival of
B. bronchiseptica
in vitro and may provide a suitable means for examining the role of long-term intracellular survival of the bacterium in the host.
Expansion of a Novel Pulmonary CD3−CD4+CD8+Cell Population in Mice duringChlamydia pneumoniaeInfection
Authors: Penttilä Jenni M. , Pyhälä Reijo , Sarvas Matti , Rautonen Nina 
Published: December 2019

ABSTRACTA new pulmonary T-cell-like lymphocyte population with the phenotype CD3−CD4+CD8+was discovered in mice. CD4+CD8+but CD3+cells among murine intestinal intraepithelial lymphocytes have previously been described. We describe herein a dramatic expansion of the CD3−CD4+CD8+cell population in response to experimental respiratory infection. After intranasalChlamydia pneumoniaeinfection, CD4+CD8+cells became transiently the dominant lymphocyte type (maximum of 87% of all lymphocytes) in the lungs of NIH/S mice but remained virtually undetectable in spleen and blood. The enrichment of these cells was not aC. pneumoniae-specific event, since infection of NIH/S mice with influenza A virus also resulted in an increase in the number of CD4+CD8+cells (maximum of 42% of all lymphocytes). In addition to outbred NIH/S mice, two other mouse strains were studied: BALB/c (H-2d) and C57BL/6 (H-2b).C. pneumoniae-infected BALB/c mice responded with an intermediate increase in the number of CD4+CD8+cells in lungs, whereas C57BL/6 mice did not respond. The double-positive CD4+CD8+cells lacked a major part of the T-cell receptor complex, being both CD3−and TCR αβ−. However, when they were stimulated in vitro with a T-cell mitogen, they responded by proliferation but did not secrete gamma interferon. The dramatic expansion of this cell population at the infection site suggests an active role for them in respiratory infection, but the specification of this requires further study.
Differential Kinetics and Distribution of Antibodies in Serum and Nasal and Vaginal Secretions after Nasal and Oral Vaccination of Humans
Authors: Rudin Anna , Johansson Eva-Liz , Bergquist Charlotta , Holmgren Jan 
Published: December 2019

ABSTRACTAlthough nasal vaccination has emerged as an interesting alternative to systemic or oral vaccination, knowledge is scarce about the immune responses after such immunization in humans. In the present study, we have compared the kinetics and organ distribution of the antibody responses after nasal and oral vaccination. We immunized female volunteers nasally or orally with cholera toxin B subunit (CTB) and determined the specific antibody levels in serum and nasal and vaginal secretions, as well as the number of circulating antibody-secreting cells, before immunization and 1, 2, 3, 6, and 26 weeks thereafter. Nasal vaccination induced 9-fold CTB-specific immunoglobulin A (IgA) and 56-fold specific IgG antibody increases in nasal secretions, whereas no significant IgA increase was seen after oral vaccination. Both oral and nasal vaccination resulted in 5- to 6-fold CTB-specific IgA and 20- to 30-fold specific IgG increases in vaginal secretions. Strong serum responses to CTB were also induced by both routes of vaccination. A notable difference between nasal and oral vaccination was that the nasal route elicited a specific antibody response with a later onset but of much longer duration than did the oral route. We conclude from this study that the nasal route is superior to the oral route for administering at least nonliving vaccines against infections in the upper respiratory tract, whereas either oral or nasal vaccination might be used for eliciting antibody responses in the female genital tract.
Low Genetic Diversity of
Haemophilus influenzae
Type b Compared to Nonencapsulated
H. influenzae
in a Population in Which
H. influenzae
Is Highly Endemic
Authors: Smith-Vaughan Heidi C. , Sriprakash Kadaba S. , Leach Amanda J. , Mathews John D. , Kemp David J. 
Published: December 2019

ABSTRACT

Immunization with
Haemophilus influenzae
type b (Hib) conjugate polysaccharide vaccines has dramatically reduced Hib disease worldwide. As in other populations, nasopharyngeal carriage of Hib declined markedly in Aboriginal infants following vaccination, although carriage has not been entirely eliminated. In this study, we describe the genetic characteristics and the carriage dynamics of longitudinal isolates of Hib, characterized by using several typing methods. In addition, carriage rates of nonencapsulated
H. influenzae
(NCHi) are high, and concurrent colonization with Hib and NCHi is common; we also observed NCHi isolates which were genetically similar to Hib. There is a continuing need to promote Hib immunization and monitor
H. influenzae
carriage in populations in which the organism is highly endemic, not least because of the possibility of genetic exchange between Hib and NCHi strains in such populations.
Neisseria gonorrhoeae
Induces Focal Polymerization of Actin in Primary Human Urethral Epithelium
Authors: Giardina Peter C. , Williams Richard , Lubaroff David , Apicella Michael A. 
Published: December 2019

ABSTRACT

The pathogenic
Neisseria
species induce cytoskeletal reorganization in immortalized cell lines. In Chang conjunctival epithelium and T84 intestinal epithelium, focal cytoskeletal rearrangements in which bacteria contacted the epithelial surface were observed. We show that actin footprints are induced in gonococcus-challenged primary urethral epithelium. Moreover, the microbes induced microvillus extension from the epithelial cell surface. Our results indicate that formation of actin footprints is not an artifact of commonly used immortalized cell lines.
Roles of Innate and Adaptive Immunity in Respiratory Mycoplasmosis
Authors: Cartner Samuel C. , Lindsey J. Russell , Gibbs-Erwin Julie , Cassell Gail H. , Simecka Jerry W. 
Published: December 2019

ABSTRACT

Current evidence suggests that host defense in respiratory mycoplasmosis is dependent on both innate and humoral immunity. To further delineate the roles of innate and adaptive immunity in antimycoplasmal defenses, we intranasally infected C3H/HeSnJ-
scid/scid
(C3H-SCID), C3H/HeSnJ (C3H), C57BL/6J-
scid/scid
(C57-SCID), and C57BL/6N (C57BL) mice with
Mycoplasma pulmonis
and at 14 and 21 days postinfection performed quantitative cultures of lungs and spleens, quantification of lung lesions, and histopathologic assessments of all other major organs. We found that numbers of mycoplasmas in lungs were associated with genetic background (C3H susceptible, C57BL resistant) rather than functional state of adaptive immunity, indicating that innate immunity is the main contributor to antimycoplasmal defense of the lungs. Extrapulmonary dissemination of mycoplasmas with colonization of spleens and histologic lesions in multiple organs was a common occurrence in all mice. The absence of adaptive immune responses in severe combined immunodeficient (SCID) mice resulted in increased mycoplasmal colonization of spleens and lesions in extrapulmonary sites, particularly spleens, hearts, and joints, and also reduced lung lesion severity. The transfer of anti-
M. pulmonis
serum to infected C3H-SCID mice prevented extrapulmonary infection and disease, while the severity of lung lesions was restored by transfer of naive spleen cells to infected C3H-SCID mice. Collectively, our results strongly support the conclusions that innate immunity provides antimycoplasmal defense of the lungs and humoral immunity has the major role in defense against systemic dissemination of mycoplasmal infection, but cellular immune responses may be important in exacerbation of mycoplasmal lung disease.
Evaluation of the Proline-Rich Antigen of
Coccidioides immitis
as a Vaccine Candidate in Mice
Authors: Kirkland Theo N. , Finley Fred , Orsborn Kris I. , Galgiani John N. 
Published: December 2019

ABSTRACT

We have expressed the proline-rich antigen (PRA) from
Coccidioides immitis
in
Escherichia coli
and evaluated its potential as a vaccine candidate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the recombinant protein (rPRA) revealed two bands, which exhibited virtually identical primary amino acid sequences. T cells from rPRA-immunized BALB/c mice showed a significant in vitro proliferative response to rPRA. A small but statistically significant proliferative response was also induced by rPRA in T cells from mice immunized with whole-cell coccidioidal vaccines. BALB/c mice immunized with rPRA and challenged intraperitoneally with virulent
C. immitis
had a greatly reduced fungal burden in their lungs and spleens compared to unvaccinated mice. The number of organisms in the lungs was reduced 500-fold, and similar reductions were observed in the spleens of immunized mice. These studies support the continued development of rPRA as a candidate vaccine for prevention of coccidioidomycosis.
Pathogenicity and Immunogenicity of aListeria monocytogenesStrain That Requiresd-Alanine for Growth
Authors: Thompson Robert J. , Bouwer H. G. Archie , Portnoy Daniel A. , Frankel Fred R. 
Published: December 2019

ABSTRACTListeria monocytogenesis an intracellular bacterial pathogen that elicits a strong cellular immune response following infection and therefore has potential use as a vaccine vector. However, while infections byL. monocytogenesare fairly rare and can readily be controlled by a number of antibiotics, the organism can nevertheless cause meningitis and death, particularly in immunocompromised or pregnant patients. We therefore have endeavored to isolate a highly attenuated strain of this organism for use as a vaccine vector.d-Alanine is required for the synthesis of the mucopeptide component of the cell walls of virtually all bacteria and is found almost exclusively in the microbial world. We have found inL. monocytogenestwo genes that control the synthesis of this compound, an alanine racemase gene (dal) and ad-amino acid aminotransferase gene (dat). By inactivating both genes, we produced an organism that could be grown in the laboratory when supplemented withd-alanine but was unable to grow outside the laboratory, particularly in the cytoplasm of eukaryotic host cells, the natural habitat of this organism during infection. In mice, the double-mutant strain was completely attenuated. Nevertheless, it showed the ability, particularly under conditions of transient suppression of the mutant phenotype, to induce cytotoxic T-lymphocyte responses and to generate protective immunity against lethal challenge by wild-typeL. monocytogenesequivalent to that induced by the wild-type organism.