bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intrapulmonary Delivery of Tumor Necrosis Factor Agonist Peptide Augments Host Defense in Murine Gram-Negative Bacterial Pneumonia
Authors: Laichalk Lauri L. , Bucknell Kathy A. , Huffnagle Gary B. , Wilkowski Jodi M. , Moore Thomas A. , Romanelli Robert J. , Standiford Theodore J. 
Published: December 2019

ABSTRACTTumor necrosis factor alpha (TNF) has been shown to be an essential cytokine mediator of innate immunity inKlebsiellapneumonia. Recently, a TNF agonist peptide consisting of the 11-amino-acid TNF binding site (TNF70-80) has been shown to possess many of the leukocyte-activating properties of TNF without the associated toxicity when administered locally or systemically. Given the beneficial effects of TNF in gram-negative pneumonia, we hypothesize that the intratracheal (i.t.) administration of TNF70-80would augment lung innate immunity in mice challenged with intrapulmonaryKlebsiella pneumoniae. The administration of TNF70-80i.t. to CBA/J mice 7 days prior to, but not concomitantly with, the i.t. delivery of 3 × 103CFU ofK. pneumoniaeresulted in a marked increase in survival compared to that of animals receiving a control peptide i.t. In addition, pretreatment with TNF70-80resulted in improved bacterial clearance, which occurred in association with enhanced lung myeloperoxidase activity (as a measure of lung polymorphonuclear leukocyte influx), and increased expression of the important activating cytokines TNF, macrophage inflammatory protein-2, interleukin-12, and gamma interferon compared that for animals receiving control peptide. Finally, the administration of TNF70-80intraperitoneally resulted in enhanced rather than decreased lethality ofKlebsiellapneumonia compared to that for animals receiving either TNF70-80or control peptide i.t. Our studies suggest that the intrapulmonary, but not systemic, administration of the TNF agonist peptide may serve as an important immunoadjuvant in the treatment of murineKlebsiellapneumonia.
Characterization of a
sar
Homolog of
Staphylococcus epidermidis
Authors: Fluckiger Ursula , Wolz Christiane , Cheung Ambrose L. 
Published: December 2019

ABSTRACT

Coagulase-negative staphylococci are common nosocomial pathogens. A regulatory element, designated
sar
, partially controls exoprotein synthesis in coagulase-positive
Staphylococcus aureus
by modulating the expression of another regulatory locus, called
agr
. We report here the cloning of a
sar
homolog in
S. epidermidis
. The major open reading frame within
sar
in
S. epidermidis
is highly homologous (84%) to the
S. aureus
SarA protein. Primer extension studies revealed three
sar
transcripts (0.64, 0.76, and 0.85 kb) initiated from three distinct promoters. The interpromoter region in
S. epidermidis
differs from its
S. aureus
counterpart, possibly suggesting target gene differences and a disparate pattern for
sar
activation. Remarkably, the
S. epidermidis sar
homolog interacts with an
agr
promoter fragment of
S. aureus
in gel shift assays. Additionally,
S. epidermidis sar
fragments could restore hemolysin production in an
S. aureus sar
mutant. As typical virulence determinants controlled by
sar
in
S. aureus
are not present in
S. epidermidis
, an examination of functional and structural similarities and divergence of
sar
in staphylococci will be of major interest.
Assimilation of Xylose, Mannose, and Mannitol for Synthesis of Glucuronoxylomannan of
Cryptococcus neoformans
Determined by
13
C Nuclear Magnetic Resonance Spectroscopy
Authors: Cherniak Robert , O’Neill Eric B. , Sheng Shuqun 
Published: December 2019

ABSTRACT

Cryptococcus neoformans
NIH 409 was cultured in a defined medium containing
d
-[1-
13
C]xylose (Xyl),
d
-[1-
13
C]mannose (Man), or
d
-[1-
13
C]mannitol as the sole carbon source. The distribution of
13
C in the Man, Xyl, glucuronic acid (GlcA), and O-acetyl constituents of native and de-O-acetylated glucuronoxylomannan (GXM) was determined by one-dimensional
13
C nuclear magnetic resonance spectroscopy. The carbon chain of Man was incorporated intact into GXM since
13
C was observed only in carbon 1 of Man, GlcA, and Xyl. The carbon chain of mannitol was incorporated intact into GXM since
13
C was observed only in carbons 1 and 6. This was expected since mannitol has an axis of symmetry. The carbon chain of Xyl was identified only in carbons 1 and 3 of Man, GlcA, and Xyl. This pattern of labeling is consistent with the assimilation of Xyl through the pentophosphate pathway.
IS
195
, an Insertion Sequence-Like Element Associated with Protease Genes in
Porphyromonas gingivalis
Authors: Lewis Janina P. , Macrina Francis L. 
Published: December 2019

ABSTRACT

Porphyromonas gingivalis
is recognized as an important etiologic agent in adult and early-onset periodontal disease. Proteases produced by this organism contribute to its virulence in mice. Protease-encoding genes have been shown to contain multiple copies of repeated nucleotide sequences. These conserved sequences have also been found in hemagglutinin genes. In the process of studying the genetic loci containing the conserved repeated sequences, we have characterized a
prtP
gene homolog from
P. gingivalis
W83 encoding a cysteine protease with Lys-X specificity. However, this
prtP
gene was interrupted by an insertion sequence-like element which we designated IS
195
. Furthermore, IS
195
and another element, IS
1126
, were present downstream of
prtP
gene homologs (
kgp
) found in
P. gingivalis
H66 and 381. IS
195
, a 1,068-bp insertion sequence-like element, contained 11-bp inverted repeats at its termini and was bordered by 9-bp direct repeats presumed to be a transposition-mediated target site duplication. Its central region contained one large open reading frame encoding a predicted 300-amino-acid protein which appeared to be a transposase. We isolated two naturally occurring variants of
P. gingivalis
W83, one carrying IS
195
within the coding region of the
prtP
gene and another containing an intact
prtP
gene. Biochemical characterization revealed a lack of trypsin-like Lys-X specific proteolytic activity in the
P. gingivalis
W83 variant carrying the disrupted
prtP
gene. Studies using a mouse model revealed a reduction of virulence resulting from insertion of IS
195
into the coding region of the
prtP
gene. An allelic-exchange mutant defective in the
prtP
gene also was constructed and tested in vivo. It displayed intermediate virulence compared to that of the wild-type and
prtP
::IS
195
mutant strains. We conclude that the Lys-X cysteine protease contributes to virulence in soft tissue infections.
Pseudomonas aeruginosaExoenzyme S Is a Mitogen but Not a Superantigen for Human T Lymphocytes
Authors: Bruno Tony F. , Buser Deborah E. , Syme Rachel M. , Woods Donald E. , Mody Christopher H. 
Published: December 2019

ABSTRACTVirtually all cystic fibrosis (CF) patients become infected withPseudomonas aeruginosa, and once the infection is established, the organism is rarely cleared. One of theP. aeruginosavirulence factors, exoenzyme S, has been shown to correlate with increased morbidity and mortality both in rat models of chronic pulmonary inflammation and in human CF patients. It has previously been shown that exoenzyme S is a potent stimulus for the proliferation of T cells in greater than 95% of adults, which could contribute to the pathogenesis of CF. The goal of this study was to determine the mechanism of T-cell stimulation by exoenzyme S in an effort to shed light on the immune response and contribute to understanding its role inP. aeruginosapathogenesis. The current studies demonstrate that exoenzyme S stimulates naive T cells, since fetal blood lymphocytes proliferated and adult lymphocytes that expressed CD45RA proliferated. The percentage of T cells activated by exoenzyme S after a 4-h culture (as measured by CD69 surface expression) was intermediate in magnitude compared to levels induced by a panel of superantigens and mitogens. To determine the mechanism of activation, the requirement for accessory cells was investigated. The proliferative response to exoenzyme S was dependent on the presence of accessory cells but was not blocked by an anti-DR antibody. Exoenzyme S activated both CD4+and CD8+T cells, but CD4+T cells were preferentially activated. The Vβ repertoire of donor T cells showed no preferential activation or preferential expansion after stimulation by exoenzyme S, suggesting that it is not a superantigen. Taken together, our data suggest that exoenzyme S is a T-cell mitogen but not a superantigen. Activation of a large percentage of T lymphocytes by exoenzyme S may produce a lymphocyte-mediated inflammatory response that should be considered in the pathogenesis of CF.
Immunization with
Pneumocystis carinii
gpA Is Immunogenic but Not Protective in a Mouse Model of
P. carinii
Pneumonia
Authors: Gigliotti Francis , Wiley James A. , Harmsen Allen G. 
Published: December 2019

ABSTRACT

Immunization with whole
Pneumocystis carinii
has been shown to protect mice from the development of
P. carinii
pneumonia (PCP) when they are subsequently immunosuppressed and challenged with viable organisms. To determine whether these results could be duplicated by using a subunit vaccine, we examined the immunogenicity and efficacy of an immunization strategy based on
P. carinii
gpA. This antigen was chosen for study because passive immunoprophylaxis, based on gpA, has been shown to be partially protective in various animal models of infection. Immunization with gpA produced an anti-gpA specific antibody response comparable to that resulting from immunization with whole organisms. However, in contrast to immunization with whole
P. carinii
, which was protective, immunization with gpA did not protect T-cell-depleted mice from the development of PCP. These studies suggest that other antigens in addition to gpA need to be evaluated for their role in protective immunity against
P. carinii.
Identification of New Cytotoxic T-Cell Epitopes on the 38-Kilodalton Lipoglycoprotein ofMycobacterium tuberculosisby Using Lipopeptides
Authors: da Fonseca Dora P. A. J. , Joosten Dianne , van der Zee Ruurd , Jue Danny L. , Singh Mahavir , Vordermeier Hans M. , Snippe Harm , Verheul André F. M. 
Published: December 2019

ABSTRACTInduction of cytotoxic T lymphocytes (CTLs) by vaccination has been shown to protect against bacterial, viral, and tumoral challenge. The aim of this study was to identify CTL epitopes on the 38-kDa lipoglycoprotein fromMycobacterium tuberculosis. The identification of these CTL epitopes was based on synthesizing peptides designed from the 38-kDa lipoglycoprotein, with known major histocompatibility complex class I (MHC-I) binding motifs (H-2Db), and studying their ability to up-regulate and stabilize MHC-I molecules on the mouse lymphoma cell line RMA-S. To improve the capacity of the identified peptides to induce CTL responses in mice, palmitic acid with a cysteine-serine-serine spacer amino acid sequence was attached to the amino terminus of the peptide. Two of five peptides with H-2Dbbinding motifs and their corresponding lipopeptides up-regulated and stabilized the H-2Dbmolecules on RMA-S cells. Both lipopeptides, in combination with incomplete Freund’s adjuvant, induced CTL responses in C57BL/6 (H-2b) mice. Moreover, the lipopeptide induced stronger CTL responses than the peptide. The capacity of the various lipopeptides to induce CTL displayed a good relationship with the ability of the (lipo)peptide to up-regulate and to stabilize H-2Dbmolecules. The capacity of the peptides and lipopeptides to up-regulate and stabilize MHC-I expression can therefore be used to predict their potential to function as a CTL epitope. The newly identified CTL epitopes and their lipid derivatives provide us with important information for futureM. tuberculosisvaccine design.
Potential Role of Epithelial Cell-Derived Histone H1 Proteins in Innate Antimicrobial Defense in the Human Gastrointestinal Tract
Authors: Rose F. R. A. J. , Bailey K. , Keyte J. W. , Chan W. C. , Greenwood D. , Mahida Y. R. 
Published: December 2019

ABSTRACT
In the human gastrointestinal tract, microorganisms are present in large numbers in the colon but are sparse in the proximal small intestine. In this study, we have shown that acid extracts of fresh human terminal ileal mucosal samples mediate antimicrobial activity. Following cation-exchange chromatography, one of the eluted fractions demonstrated antibacterial activity against bacteria normally resident in the human colonic lumen. This activity was further fractionated by reverse-phase high-performance liquid chromatography and identified as histone H1 and its fragments. We have also shown that in tissue sections, immunoreactive histone H1 is present in the cytoplasm of villus epithelial cells. In vitro culturing of detached (from the basement membrane) villus epithelial cells led to the release of antimicrobial histone H1 proteins, while the cells demonstrated ultrastructural features of programmed cell death. Our studies suggest that cytoplasmic histone H1 may provide protection against penetration by microorganisms into villus epithelial cells. Moreover, intestinal epithelial cells released into the lumen may mediate antimicrobial activity by releasing histone H1 proteins and their fragments.
Identification and Characterization of Staphylococcal Enterotoxin Types G and I from
Staphylococcus aureus
Authors: Munson Sibyl H. , Tremaine Mary T. , Betley Marsha J. , Welch Rodney A. 
Published: December 2019

ABSTRACT

Staphylococcal enterotoxins are exotoxins produced by
Staphylococcus aureus
that possess emetic and superantigenic properties. Prior to this research there were six characterized enterotoxins, staphylococcal enterotoxin types A to E and H (referred to as SEA to SEE and SEH). Two new staphylococcal enterotoxin genes have been identified and designated
seg
and
sei
(staphylococcal enterotoxin types G and I, respectively).
seg
and
sei
consist of 777 and 729 nucleotides, respectively, encoding precursor proteins of 258 (SEG) and 242 (SEI) deduced amino acids. SEG and SEI have typical bacterial signal sequences that are cleaved to form toxins with 233 (SEG) and 218 (SEI, predicted) amino acids, corresponding to mature proteins of 27,043 Da (SEG) and 24,928 Da (SEI). Biological activities for SEG and SEI were determined with recombinant
S. aureus
strains. SEG and SEI elicited emetic responses in rhesus monkeys upon nasogastric administration and stimulated murine T-cell proliferation with the concomitant production of interleukin 2 (IL-2) and gamma interferon (IFN-γ), as measured by cytokine enzyme-linked immunoassays. SEG and SEI are related to other enterotoxins of
S. aureus
and to streptococcal pyrogenic exotoxin A (SpeA) and streptococcal superantigen (SSA) of
Streptococcus pyogenes
. Phylogenetic analysis and comparisons of amino acid and nucleotide sequence identities were performed on related staphylococcal and streptococcal protein toxins to group SEG and SEI among the characterized toxins. SEG is most similar to SpeA, SEB, SEC, and SSA (38 to 42% amino acid identity), while SEI is most similar to SEA, SEE, and SED (26 to 28% amino acid identity). Polyclonal antiserum was generated against purified histidine-tagged SEG and SEI (HisSEG and HisSEI). Immunoblot analysis of the enterotoxins, toxic-shock syndrome toxin 1, and SpeA with antiserum prepared against HisSEG and HisSEI revealed that SEG shares some epitopes with SEC1 while SEI does not.
Susceptibility toSalmonella typhimuriumInfection and Effectiveness of Vaccination in Mice Deficient in the Tumor Necrosis Factor Alpha p55 Receptor
Authors: Everest Paul , Roberts Mark , Dougan Gordon 
Published: December 2019

ABSTRACTMice defective in the ability to produce the tumor necrosis factor alpha p55 receptor (TNFαp55R) were orally challenged with a number ofSalmonella typhimuriumHWSH derivatives that differ in virulence. In comparison to TNFαp55R+/+mice, TNFαp55R−/−mice succumbed earlier to challenge with wild-typeS. typhimuriumHWSH andS. typhimuriumHWSHpurE. In contrast, TNFαp55R−/−mice were able to control anS. typhimuriumHWSHaroAchallenge, although greater numbers ofSalmonellaorganisms were present in the tissues for a longer time period than was observed with TNFαp55R+/+mice. Vaccination of normal and TNFαp55R knockout animals withS. typhimuriumHWSHaroAshowed that TNFαp55R−/−mice, unlike TNFαp55R+/+mice, were not protected against a virulentS. typhimuriumHWSH challenge. Splenocytes from TNFαp55R−/−mice exhibited a reduced ability to proliferate in the presence ofS. typhimuriumantigen compared to TNFαp55R+/+mice. Thus, TNFαp55R is essential for controllingSalmonellagrowth in tissues and for recall of immunity in murine salmonellosis.
Study of Immunization against Anthrax with the Purified Recombinant Protective Antigen of
Bacillus anthracis
Authors: Singh Yogendra , Ivins Bruce E. , Leppla Stephen H. 
Published: December 2019

ABSTRACT

Protective antigen (PA) of anthrax toxin is the major component of human anthrax vaccine. Currently available human vaccines in the United States and Europe consist of alum-precipitated supernatant material from cultures of toxigenic, nonencapsulated strains of
Bacillus anthracis
. Immunization with these vaccines requires several boosters and occasionally causes local pain and edema. We previously described the biological activity of a nontoxic mutant of PA expressed in
Bacillus subtilis
. In the present study, we evaluated the efficacy of the purified mutant PA protein alone or in combination with the lethal factor and edema factor components of anthrax toxin to protect against anthrax. Both mutant and native PA preparations elicited high anti-PA titers in Hartley guinea pigs. Mutant PA alone and in combination with lethal factor and edema factor completely protected the guinea pigs from
B. anthracis
spore challenge. The results suggest that the mutant PA protein may be used to develop an effective recombinant vaccine against anthrax.
Two-Dimensional Electrophoresis for Analysis ofMycobacterium tuberculosisCulture Filtrate and Purification and Characterization of Six Novel Proteins
Authors: Weldingh Karin , Rosenkrands Ida , Jacobsen Susanne , Rasmussen Peter Birk , Elhay Martin J. , Andersen Peter 
Published: December 2019

ABSTRACTCulture filtrate fromMycobacterium tuberculosiscontains molecules which promote high levels of protective immunity in animal models of subunit vaccination against tuberculosis. We have used two-dimensional electrophoresis for analysis and purification of six novelM. tuberculosisculture filtrate proteins (CFPs): CFP17, CFP20, CFP21, CFP22, CFP25, and CFP28. The proteins were tested for recognition byM. tuberculosis-reactive memory cells from different strains of inbred mice and for their capacity to induce a skin test response inM. tuberculosis-infected guinea pigs. CFP17, CFP20, CFP21 and CFP25 induced both a high gamma interferon release and a strong delayed-type hypersensitivity response, and CFP21 was broadly recognized by different strains of inbred mice. N-terminal sequences were obtained for the six proteins, and the corresponding genes were identified in the SangerM. tuberculosisgenome database. In parallel we established a two-dimensional electrophoresis reference map of short-term culture filtrate components and mapped novel proteins as well as already-known CFP.
Mapping of Specific and Promiscuous HLA-DR-Restricted T-Cell Epitopes on thePlasmodium falciparum27-Kilodalton Sexual Stage-Specific Antigen
Authors: Contreras Carmen E. , Ploton Isabelle N. , Siliciano Robert F. , Karp Christopher L. , Viscidi Raphael , Kumar Nirbhay 
Published: December 2019

ABSTRACTWe have characterized HLA-DR-restricted T-cell epitopes on the 27-kDa protein (Pfg27), a sexual stage-specific antigen, of the human malaria parasitePlasmodium falciparumin subjects with a history of malaria. Pfg27, expressed early in the sexual stages, is recognized by monoclonal antibodies capable of reducing the infectivity of gametocytes in mosquitoes. By using 16 Pfg27-specific CD4+-T-cell clones derived from three donors, seven different T-cell epitopes were identified. Among them, P11 (amino acids 191 to 210 of the Pfg27 sequence, IDVVDSYIIKPIPALPVTPD) was found to contain a previously described binding motif for multiple HLA-DR allotypes. Indeed, P11 was found to be promiscuous in that it could be recognized by T cells in the context of at least five different HLA-DR molecules. The cytokine profile of the clones was mixed. Seven of nine T-cell clones exhibited a Th0-like cytokine profile, producing high levels of gamma interferon (IFN-γ) and interleukin-4 (IL-4) upon stimulation with specific peptides and mitogens. The other two clones had a Th1-like cytokine profile with high expression of IFN-γ and no IL-4. Identification of a promiscuous epitope in Pfg27 could play a significant role in the design of a subunit vaccine for suppressing malaria transmission.
Phylogenetic Analysis of theChlamydia trachomatisMajor Outer Membrane Protein and Examination of Potential Pathogenic Determinants
Authors: Stothard Diane R. , Boguslawski George , Jones Robert B. 
Published: December 2019

ABSTRACTPhylogenetic analysis was utilized to investigate biological relationships (tissue tropism, disease presentation, and epidemiologic success), as evidenced by coevolution, among human strains ofChlamydia trachomatis. Nucleotide sequences ofomp1, the gene encoding the major outer membrane protein (MOMP) ofC. trachomatis, were determined for 40 strains representing 11 serovars. These data were combined with availableomp1sequences from GenBank for an analysis encompassing a total of 69 strains representing 17 serovars infecting humans. Phylogenetic analysis of the nucleotide and inferred amino acid sequences showed no evolutionary relationships among serovars that corresponded to biological or pathological phenotypes (tissue tropism, disease presentation, and epidemiologic success). In addition, no specific residues that may have evolved to play a role in determining biologically relevant characteristics of chlamydia, such as tissue specificity, disease presentation, and epidemiologic success, were apparent in the MOMP. These results suggest that variation in MOMP may have arisen from a need to be diverse in the presence of immune pressure rather than as a function of pathogenicity. Therefore, the role of MOMP in disease pathogenesis and infection may be passive, and it may not be the major ligand responsible for directing infection of various human cell types.