bluuebunny/crossref_metadata_2025_split huggingface dataset:
In Vivo Regulation of ReplicativeLegionella pneumophilaLung Infection by Endogenous Interleukin-12
Authors: Brieland J. K. , Remick D. G. , LeGendre M. L. , Engleberg N. C. , Fantone J. C. 
Published: December 2019

ABSTRACTThe in vivo role of endogenous interleukin 12 (IL-12) in modulating intrapulmonary growth ofLegionella pneumophilawas assessed by using a murine model of replicativeL. pneumophilalung infection. Intratracheal inoculation of A/J mice with virulent bacteria (106L. pneumophilacells per mouse) resulted in induction of IL-12, which preceded clearance of the bacteria from the lung. Inhibition of endogenous IL-12 activity, via administration of IL-12 neutralizing antiserum, resulted in enhanced intrapulmonary growth of the bacteria within 5 days postinfection (compared to untreatedL. pneumophila-infected mice). Because IL-12 has previously been shown to modulate the expression of cytokines, including gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and IL-10, which regulateL. pneumophilagrowth, immunomodulatory effects of endogenous IL-12 on intrapulmonary levels of these cytokines during replicativeL. pneumophilalung infection were subsequently assessed. Results of these experiments demonstrated that TNF-α activity was significantly lower, while protein levels of IFN-γ and IL-10 in the lung were similar, inL. pneumophila-infected mice administered IL-12 antiserum, compared to similarly infected untreated mice. Together, these results demonstrate that IL-12 is critical for resolution of replicativeL. pneumophilalung infection and suggest that regulation of intrapulmonary growth ofL. pneumophilaby endogenous IL-12 is mediated, at least in part, by TNF-α.
Antigenic Determinants of
Staphylococcus aureus
Type 5 and Type 8 Capsular Polysaccharide Vaccines
Authors: Fattom Ali I. , Sarwar Jawad , Basham Lisa , Ennifar Sofiane , Naso Robert 
Published: December 2019

ABSTRACT

Bacterial capsular polysaccharides (CP) are carbohydrate polymers comprised of repeating saccharide units. Several of these CP have side chains attached to their backbone structures. The side chains may include O-acetyl, phosphate, sialic acid, and other moieties. Those moieties represent the immunodominant epitopes and the most functional ones. The clinically significant
Staphylococcus aureus
type 5 CP (CP 5) and type 8 CP (CP 8) are comprised of a trisaccharide repeat unit with one O-acetyl group attached to each repeat unit. The immunogenicity of these CP and the functionality of antibodies to the backbone and the O-acetyl moieties were investigated. Immunization with the native CP conjugates (CP with 75% O-acetylation) elicited a high proportion of antibodies directed against the O-acetyl moiety. Nonetheless, all of the vaccinees produced antibodies to the backbone moieties as well. Conjugate vaccines made of de-O-acetylated CP elicited backbone antibodies only. Antibodies to both backbone and O-acetyl groups were found to be opsonic against
S. aureus
strains which varied in their O-acetyl content. Absorption studies with O-acetylated and de-O-acetylated CP showed that (i) native CP conjugates generated antibodies to both backbone and O-acetyl groups and (ii) O-acetylated isolates were opsonized by both populations of antibodies while the non-O-acetylated strains were predominantly opsonized by the backbone antibodies. These results suggest that
S. aureus
CP conjugate vaccines elicit multiple populations of antibodies with diverse specificities. Moreover, the antibodies of different specificities (backbone or O-acetyl) are all functional and efficient against the variations in bacterial CP that may occur among clinically significant
S. aureus
pathogenic isolates.
Induction of Adrenomedullin mRNA and Protein by Lipopolysaccharide and Paclitaxel (Taxol) in Murine Macrophages
Authors: Zaks-Zilberman Meirav , Salkowski Cindy A. , Elsasser Theodore , Cuttitta Frank , Vogel Stefanie N. 
Published: December 2019

ABSTRACTLipopolysaccharide (LPS), a potent inflammatory stimulus derived from the outer membrane of gram-negative bacteria, has been implicated in septic shock. Plasma levels of adrenomedullin (AM), a potent vasorelaxant, are increased in septic shock and possibly contribute to the characteristic hypotension. As macrophages play a central role in the host response to LPS, we studied AM production by LPS-stimulated macrophages. When peritoneal exudate macrophages from C3H/OuJ mice were treated with protein-free LPS (100 ng/ml) or the LPS mimetic paclitaxel (Taxol; 35 μM), an ∼10-fold increase in steady-state AM mRNA levels was observed, which peaked between 2 and 4 h. A three- to fourfold maximum increase in the levels of immunoreactive AM protein was detected after 6 to 8 h of stimulation. While LPS-hyporesponsive C3H/HeJ macrophages failed to respond to protein-free LPS with an increase in steady-state AM mRNA levels, increased levels were observed after stimulation of these cells with a protein-rich (butanol-extracted) LPS preparation. In addition, increased AM mRNA was observed following treatment of either C3H/OuJ or C3H/HeJ macrophages with solubleToxoplasma gondiitachyzoite antigen or the synthetic flavone analog 5,6-dimethylxanthenone-4-acetic acid. Gamma interferon also stimulated C3H/OuJ macrophages to express increased AM mRNA levels yet was inhibitory in the presence of LPS or paclitaxel. In vivo, mice challenged intraperitoneally with 25 μg of LPS exhibited increased AM mRNA levels in the lungs, liver, and spleen; the greatest increase (>50-fold) was observed in the liver and lungs. Thus, AM is produced, by murine macrophages, and furthermore, LPS induces AM mRNA in vivo in a number of tissues. These data support a possible role for AM in the pathophysiology of sepsis and septic shock.
The Number of Direct Repeats in
hagA
Is Variable among
Porphyromonas gingivalis
Strains
Authors: Kozarov Emil , Whitlock J. , Dong H. , Carrasco E. , Progulske-Fox A. 
Published: December 2019

ABSTRACT

The coding sequence for the surface protein hemagglutinin A (HagA) of
Porphyromonas gingivalis
381 has previously been shown to contain four direct 1.35-kb repeats, designated
rep
HA
. This study was performed to determine if the number of
rep
HA
units in
hagA
is consistently 4 or if allelic polymorphism exists among strains and/or upon multiple passage of
P. gingivalis
. To this end, primers which were homologous to the regions directly 5′ and 3′ of the repeat domain in
hagA
were synthesized. PCR conditions which allowed amplification of the 8.4-kb repeat region between the primers in
P. gingivalis
381 were established. Genomic DNA templates from 13 other
P. gingivalis
strains and 9 fresh clinical isolates from patients were analyzed under the same conditions as used above. Analysis of these PCR products demonstrated that the strains tested had different numbers (two to four) of
rep
HA
units in the respective
hagA
genes. The PCR products of 8.4, 7.0, and 5.7 kb represent four, three, and two repeats, respectively. One strain from each group (381, four repeats; W83, three repeats; and AJW4, two repeats) was also tested to determine if the number of repeats remained invariant upon passaging onto solid medium. No variability in the number of repeats in
hagA
within a strain was detected after 18 passages.
P. gingivalis
381 was chosen for further testing in a mouse abscess model to determine if conditions of in vivo growth would select for deletions or duplications of the repeated sequences. Five days after infection, no change in the number of repeats was detected in cells recovered from either nonimmunized or preimmunized mice. This data indicates an interstrain variability of the number of repeat units and hence a size variability of the HagA protein of
P. gingivalis
, but unlike some surface antigens of other pathogenic species, the number of repeats remains relatively stable given the conditions of growth tested here.
Immunologic and Structural Relationships of the Minor Pilus Subunits among
Haemophilus influenzae
Isolates
Authors: McCrea Kirk W. , St. Sauver Jennifer L. , Marrs Carl F. , Clemans Daniel , Gilsdorf Janet R. 
Published: December 2019

ABSTRACT

Two proteins, HifD and HifE, have been identified as structural components of
Haemophilus influenzae
pili. Both are localized at the pilus tip, and HifE appears to mediate pilus adherence to host cells. In this study we examined the immunologic and structural diversity of these pilus subunits among type b
H. influenzae
(Hib) and nontypeable
H. influenzae
(NTHI) strains. Western immunoblot analysis revealed that antibodies directed against the C terminus of HifD and HifE from Hib strain Eagan bound to HifD and HifE proteins, respectively, of all piliated Hib and NTHI strains tested. Whole-cell enzyme-linked immunosorbent assays showed that antibodies specific for native HifD or HifE of strain Eagan also bound to all piliated Hib strains but did not bind to the piliated NTHI strains. Antibodies against HifE of strain Eagan inhibited the binding of Hib to human erythrocytes but did not inhibit the binding of NTHI strains. Restriction fragment length polymorphism (RFLP) analysis was used to determine strain-to-strain structural differences within
hifD
and
hifE
genes, either by PCR or by nucleotide sequence analysis. DNA and derived amino acid sequence analyses of HifD and HifE confirmed the uniqueness of the RFLP types. The
hifD
and
hifE
genes of all type b strains showed identical restriction patterns. Analysis of
hifD
and
hifE
genes from the NTHI strains, however, revealed seven unique RFLP patterns, suggesting that these genes encode proteins with diverse primary structures. These results indicate that HifD and HifE are immunologically and structurally similar among the Hib strains but vary among the NTHI strains.
Murine Dendritic Cells Pulsed In Vitro withToxoplasma gondiiAntigens Induce Protective Immunity In Vivo
Authors: Bourguin Isabelle , Moser Muriel , Buzoni-Gatel Dominique , Tielemans Françoise , Bout Daniel , Urbain Jacques , Leo Oberdan 
Published: December 2019

ABSTRACTThe activation of a predominant T-helper-cell subset plays a critical role in disease resolution. In the case ofToxoplasma gondii, the available evidence indicates that CD4+protective cells belong to the Th1 subset. The aim of this study was to determine whetherT. gondiiantigens (inT. gondiisonicate [TSo]) presented by splenic dendritic cells (DC) were able to induce a specific immune response in vivo and to protect CBA/J mice orally challenged withT. gondiicysts. CBA/J mice immunized with TSo-pulsed DC exhibited significantly fewer cysts in their brains after oral infection withT. gondii76K than control mice did. Protected mice developed a strong humoral response in vivo, with especially high levels of anti-TSo immunoglobulin G2a antibodies in serum.T. gondiiantigens such as SAG1 (surface protein), SAG2 (surface protein), MIC1 (microneme protein), ROP2 through ROP4 (rhoptry proteins), and MIC2 (microneme protein) were recognized predominantly. Furthermore, DC loaded with TSo, which synthesized high levels of interleukin-12 (IL-12), triggered a strong cellular response in vivo, as assessed by the proliferation of lymph node cells in response to TSo restimulation in vitro. Cellular proliferation was associated with gamma interferon and IL-2 production. Taken together, these results indicate that immunization of CBA/J mice with TSo-pulsed DC can induce both humoral and Th1-like cellular immune responses and affords partial resistance against the establishment of chronic toxoplasmosis.
Borrelia burgdorferiand Interleukin-1 Promote the Transendothelial Migration of Monocytes In Vitro by Different Mechanisms
Authors: Burns Margaret J. , Furie Martha B. 
Published: December 2019

ABSTRACTA prominent feature of Lyme disease is the perivascular accumulation of mononuclear leukocytes. Incubation of human umbilical vein endothelial cells (HUVEC) cultured on amniotic tissue with either interleukin-1 (IL-1) orBorrelia burgdorferi, the spirochetal agent of Lyme disease, increased the rate at which human monocytes migrated across the endothelial monolayers. Very late antigen 4 (VLA-4) and CD11/CD18 integrins mediated migration of monocytes across HUVEC exposed to eitherB. burgdorferior IL-1 in similar manners. Neutralizing antibodies to the chemokine monocyte chemoattractant protein 1 (MCP-1) inhibited the migration of monocytes across unstimulated, IL-1-treated, orB. burgdorferi-stimulated HUVEC by 91% ± 3%, 65% ± 2%, or 25% ± 22%, respectively. Stimulation of HUVEC withB. burgdorferialso promoted a 6-fold ± 2-fold increase in the migration of human CD4+T lymphocytes. Although MCP-1 played only a limited role in the migration of monocytes acrossB. burgdorferi-treated HUVEC, migration of CD4+T lymphocytes across HUVEC exposed to spirochetes was highly dependent on this chemokine. The anti-inflammatory cytokine IL-10 reduced both migration of monocytes and endothelial production of MCP-1 in response toB. burgdorferiby approximately 50%, yet IL-10 inhibited neither migration nor secretion of MCP-1 when HUVEC were stimulated with IL-1. Our results suggest that activation of endothelium byB. burgdorferimay contribute to formation of the chronic inflammatory infiltrates associated with Lyme disease. The transendothelial migration of monocytes that is induced byB. burgdorferiis significantly less dependent on MCP-1 than is migration induced by IL-1. Selective inhibition by IL-10 further indicates thatB. burgdorferiand IL-1 employ distinct mechanisms to activate endothelial cells.
T-Cell Recognition of Mycobacterial GroES Peptides in Thai Leprosy Patients and Contacts
Authors: Chua-Intra Boosbun , Peerapakorn Somchai , Davey Nick , Jurcevic Stipo , Busson Marc , Vordermeier H. Martin , Pirayavaraporn Charoon , Ivanyi Juraj 
Published: December 2019

ABSTRACTWe report here the mapping of T-cell-stimulatory determinants of the GroES 10-kDa heat shock protein homologues fromMycobacterium lepraeandMycobacterium tuberculosis, which are known as major immunogens in mycobacterial infections. Peripheral blood mononuclear cells (PBMC) from treated tuberculoid leprosy or lepromatous leprosy patients and from healthy household or hospital staff contacts of the patients were cultured with 20 16-mer peptides covering the entire sequences of bothM. lepraeandM. tuberculosisGroES. The total number of recognized peptides was found to be the largest in family contacts, while responder frequencies to the individual tested peptides varied (5 to 80%) with specificity between the patient and contact groups. Proliferative responses to some peptides showed positive or negative associations of low statistical significance with DR and DQ alleles, though responses to most GroES peptides were genetically permissive. Notably, the sequence of the 25–40 peptide ofM. leprae, but not that ofM. tuberculosis, was more frequently stimulatory in tuberculoid leprosy patients than in either group of sensitized healthy contacts. This peptide bound to a number of HLA-DR molecules, of which HLA-DRB5*0101 had the strongest affinity. The epitope core binding to this allele was localized to the 29-to-37 sequence, and its key residue was localized to theM. leprae-specific glutamic acid at position 32. This epitope may be of interest for the development of a blood test- or skin test-based diagnostic reagent for tuberculoid leprosy, subject to further clinical evaluation in untreated patients.
Effects of Orally Administered Epidermal Growth Factor on Enteropathogenic
Escherichia coli
Infection in Rabbits
Authors: Buret Andre , Olson Merle E. , Gall D. Grant , Hardin James A. 
Published: December 2019

ABSTRACT

The increased intestinal absorption induced by epidermal growth factor (EGF) is associated with diffuse lengthening of brush border microvilli. The aim of this study was to examine the in vivo effects of oral administration of EGF during infection with enteropathogenic
Escherichia coli
. New Zealand White rabbits (4 weeks old) received orogastric EGF daily starting 3 days prior to infection with enteropathogenic
E. coli
RDEC-1 and were compared with sham-treated infected animals and uninfected controls. Weight gain, food intake, fecal
E. coli
, and stool consistency were assessed daily. On day 10, segments of jejunum, ileum, proximal, and distal colon were assessed for gram-negative bacterial colonization, disaccharidase activities, and epithelial ultrastructure. Effects of EGF on
E. coli
RDEC-1 proliferation were studied in vitro.
E. coli
RDEC-1 caused diarrhea and reduced weight gain. Seven days postinfection, the small and large intestines were colonized with numerous bacteria, brush border microvilli were disrupted, and maltase and sucrase activities were significantly reduced in the jejunum. Daily treatment with EGF prevented the occurrence of diarrhea and reduction of weight gain. These effects were associated with significant inhibition of
E. coli
colonization in the small and large intestine, improved jejunal maltase and sucrase activities and reduced microvillous injury. EGF did not affect the proliferation of
E. coli
in vitro. The findings suggest that EGF protects the gastrointestinal tract against colonization by enteropathogenic
E. coli.
Interleukin-12 Has a Role in Mediating Resistance of Murine Strains to Tyzzer’s Disease
Authors: Van Andel Roger A. , Hook Reuel R. , Franklin Craig L. , Besch-Williford Cynthia L. , Riley Lela K. 
Published: December 2019

ABSTRACTClostridium piliformeinduces enterohepatic disease in many domestic and laboratory animal species. Susceptibility to infection is known to vary with the immune status and strain of the host, but little is known about specific immune mechanisms that regulate this disease. To evaluate host control ofC. piliformeinfection, we examined the role of interleukin-12 (IL-12) both in the control of and in the response to murineC. piliformeinfection. For this study, 3-week-oldC. piliforme-resistant C57BL/6 or -susceptible DBA/2 mice were infected intravenously with either the toxic H1 or the nontoxic M1C. piliformeisolate. Serum and liver samples were collected prior toC. piliformeinoculation (day 0) and at days 1, 3, 7, 14, and 28 postinoculation. Evaluation of hepatic IL-12 p40 mRNA expression by reverse transcription-PCR and of total-IL-12 protein levels in serum by enzyme-linked immunosorbent assay revealed thatC. piliformeinduced elevations in both hepatic p40 mRNA and serum total-IL-12 levels at all times postinoculation. Elevations were similar with both toxic and nontoxicC. piliformeisolates. Levels of total IL-12 in serum were significantly (P< 0.05) higher in C57BL/6 mice than in DBA/2 mice. Additional experiments were performed in which polyclonal antibody treatment was used to neutralize IL-12 in mice of both strains prior to intravenous inoculation with toxicC. piliformeH1. IL-12 neutralization increased the severity of Tyzzer’s disease at day 3 postinoculation in both mouse strains, but the degree of increase was greater in C57BL/6 mice than in DBA/2 mice.
Production of Interleukin-12 by Murine Macrophages in Response to Bacterial Peptidoglycan
Authors: Lawrence Christine , Nauciel Charles 
Published: December 2019

ABSTRACTPeptidoglycan (PG), a component of the bacterial cell wall, has various immunomodulating activities, including the capacity to induce delayed-type hypersensitivity reactions to antigens administered in Freund’s adjuvant. We report that PG induces interleukin-12 (IL-12) mRNA production and IL-12 secretion by mouse macrophages. The capacity of PG to induce IL-12 production, like its previously reported immunomodulating activities, was dependent on the structure of its peptide subunit. PG fromBacillus megateriumandStaphylococcus aureusinduced IL-12 production, whereas PG fromMicrococcus luteusandCorynebacterium poinsettiaedid not. The ability of most bacterial PGs to induce IL-12 production suggests that they play an important role in triggering host defense mechanisms against bacterial infections.
A
Chlamydia pneumoniae
Component That Induces Macrophage Foam Cell Formation Is Chlamydial Lipopolysaccharide
Authors: Kalayoglu Murat V. , Byrne Gerald I. 
Published: December 2019

ABSTRACT

Chlamydia pneumoniae
infection is associated with atherosclerotic heart and vessel disease, but a causal relationship between this pathogen and the disease process has not been established. Recently, it was reported that
C. pneumoniae
induces human macrophage foam cell formation, a key event in early atheroma development, suggesting a role for the organism in atherogenesis. This study further examines
C. pneumoniae
-induced foam cell formation in the murine macrophage cell line RAW-264.7. Infected RAW cells accumulated cholesteryl esters when cultured in the presence of low-density lipoprotein in a manner similar to that described for human macrophages. Exposure of
C. pneumoniae
elementary bodies to periodate, but not elevated temperatures, inhibited cholesteryl ester accumulation, suggesting a role for chlamydial lipopolysaccharide (cLPS) in macrophage foam cell formation. Purified cLPS was found to be sufficient to induce cholesteryl ester accumulation and foam cell formation. Furthermore, the LPS antagonist lipid X inhibited
C. pneumoniae
and cLPS-induced lipid uptake. These data indicate that cLPS is a
C. pneumoniae
component that induces macrophage foam cell formation and suggest that infected macrophages chronically exposed to cLPS may accumulate excess cholesterol to contribute to atheroma development.
New Scavenger Receptor-Like Receptors for the Binding of Lipopolysaccharide to Liver Endothelial and Kupffer Cells
Authors: van Oosten Marijke , van de Bilt Erika , van Berkel Theo J. C. , Kuiper Johan 
Published: December 2019

ABSTRACTLipopolysaccharide (LPS) is cleared from the blood mainly by the liver. The Kupffer cells are primarily responsible for this clearance; liver endothelial and parenchymal cells contribute to a lesser extent. Although several binding sites have been described, only CD14 is known to be involved in LPS signalling. Among the other LPS binding sites that have been identified are scavenger receptors. Scavenger receptor class A (SR-A) types I and II are expressed in the liver on endothelial cells and Kupffer cells, and a 95-kDa receptor, identified as macrosialin, is expressed on Kupffer cells. In this study, we examined the role of scavenger receptors in the binding of LPS by the liver in vivo and in vitro. Fucoidin, a scavenger receptor ligand, significantly reduced the clearance of125I-LPS from the serum and decreased the liver uptake of125I-LPS about 40%. Within the liver, the in vivo binding of125I-LPS to Kupffer and liver endothelial cells was decreased 72 and 71%, respectively, while the binding of125I-LPS to liver parenchymal cells increased 34% upon fucoidin preinjection. Poly(I) inhibited the binding of125I-LPS to Kupffer and endothelial cells in vitro 73 and 78%, respectively, while poly(A) had no effect. LPS inhibited the binding of acetylated low-density lipoprotein (acLDL) to Kupffer and liver endothelial cells 40 and 55%, respectively, and the binding of oxidized LDL (oxLDL) to Kupffer and liver endothelial cells 65 and 61%, respectively. oxLDL and acLDL did not significantly inhibit the binding of LPS to these cells. We conclude that on both endothelial cells and Kupffer cells, LPS binds mainly to scavenger receptors, but SR-A and macrosialin contribute to a limited extent to the binding of LPS.