bluuebunny/crossref_metadata_2025_split huggingface dataset:
Time Course of Humoral and Cell-Mediated Immune Responses to Human Papillomavirus Type 16 in Infected Women
Authors: Nakagawa Mayumi , Viscidi Raphael , Deshmukh Ian , Costa Maria Da , Palefsky Joel M. , Farhat Sepideh , Moscicki Anna-Barbara 
Published: July 2002

ABSTRACT
The time course of cell-mediated and humoral immune responses was elucidated in eight women with human papillomavirus type 16 (HPV-16) infection by performing serial HPV-16 E6 and E7 cytotoxic T-lymphocyte (CTL) assays and HPV-16 virus-like particle (VLP) antibody analyses. Four subjects had a single incident of HPV-16 DNA detection, and four subjects had two periods of HPV-16 DNA detection. In two of the women in the latter group, the second episode of HPV-16 detection occurred in the presence of high titers of HPV-16 VLP antibody, bringing into question the protective role of humoral immunity in preventing repeated infection. However, all four subjects rapidly became HPV-16 DNA negative following the second detection of HPV-16 DNA, suggesting the presence of immunological memory. In addition, one subject rapidly became negative for HPV-16 DNA despite having no evidence of CTL or VLP antibody response prior to the second HPV-16 DNA detection, suggesting the presence of immunological responses at an undetectable level. Overall, seven of eight subjects (88%) had detectable HPV-16 E6 and/or E7 CTL responses and seven of eight women (88%) had detectable HPV-16 VLP antibody responses.
Ability of the Borreliacidal Antibody Test To Confirm Lyme Disease in Clinical Practice
Authors: Callister Steven M. , Jobe Dean A. , Agger William A. , Schell Ronald F. , Kowalski Todd J. , Lovrich Steven D. , Marks Jennifer A. 
Published: July 2002

ABSTRACTHighly specific borreliacidal antibodies are induced by infection withBorrelia burgdorferi, and a borreliacidal antibody test (BAT) may be an accurate laboratory procedure for confirming Lyme disease in clinical practice. To investigate this, 34 Lyme disease sera and 34 sera from patients with other illnesses who had presented to a primary-care facility located in an area of borreliosis endemicity were tested by the BAT and Western blotting (WB). The BAT was more sensitive (79% versus 65%;P= 0.090), especially in cases in which patients had a single erythema migrans lesion (P= 0.021). In addition, the potentially cross-reactive sera were negative by the BAT but WB yielded three (9%) false-positive results. The results from 104 sera from possible Lyme disease patients demonstrated the clinical usefulness of the more sensitive and specific BAT. The BAT was positive for 40 (38%) sera from patients with Lyme disease-related symptoms and appropriate clinical and epidemiological findings. WB confirmed Lyme disease in 30 (75%) of the 40 BAT-positive patients but failed to detectB. burgdorferiinfection in 10 BAT-positive patients. WB was also positive for 11 BAT-negative sera, but six (55%) patients had case histories which suggested that the results were false positives. Collectively, the results confirm that the BAT is a sensitive and highly specific test and suggest that widespread use would increase the accuracy of serodiagnostic confirmation of Lyme disease.
Influence of Antimalarial Treatment on Acquisition of Immunity in
Plasmodium berghei
NK65 Malaria
Authors: Long Ton That Ai , Nakazawa Shusuke , Huaman Maria Cecilia , Kanbara Hiroji 
Published: July 2002

ABSTRACT

Antimalarial treatments during primary
Plasmodium berghei
NK65 infection in BALB/c mice influenced the acquisition of protective immunity against reinfection. Among subcurative treatments, lower doses better enable mice to acquire protective immunity than do higher doses. Eradication of parasites from the start of infection did not promote protective immunity.
Interleukin-8 and Tumor Necrosis Factor Alpha Production in Human Epidermal Keratinocytes Induced byTrichophyton mentagrophytes
Authors: Nakamura Yuka , Kano Rui , Hasegawa Atsuhiko , Watanabe Shinichi 
Published: July 2002

ABSTRACTProduction of interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α) was confirmed by enzyme-linked immunosorbent assay in a medium where human epidermal keratinocytes were cocultured withTrichophyton mentagrophytesfor 1 to 12 h. IL-8 and TNF-α mRNAs were also detected in the keratinocytes cocultured withT. mentagrophytes.
Immunization with the Recombinant PorB Outer Membrane Protein Induces a Bactericidal Immune Response against
Neisseria meningitidis
Authors: Wright J. Claire , Williams Jeannette N. , Christodoulides Myron , Heckels John E. 
Published: July 2002

ABSTRACT

Infections with
Neisseria meningitidis
are characterized by life-threatening meningitis and septicemia. The meningococcal porin proteins from serogroup B meningococci have been identified as candidates for inclusion in vaccines to prevent such infections. In this study, we investigated the vaccine potential of the PorB porin protein free of other meningococcal components. The
porB
gene from a strain of
Neisseria meningitidis
expressing the class 3 outer membrane porin protein (PorB3) was cloned into the pRSETB vector, and the protein was expressed at high levels in a heterologous host
Escherichia coli
. The recombinant protein was purified to homogeneity by affinity chromatography and used for immunization after incorporation into liposomes and into micelles composed either of zwitterionic detergent or nondetergent sulfobetaine. The immunogenicity of these preparations was compared to recombinant PorB protein adsorbed to Al(OH)
3
adjuvant as a control. Although sera raised against the protein adsorbed to Al(OH)
3
reacted with the purified recombinant protein, sera raised against liposomes and micelles showed greater activity with native protein, as measured by enzyme immunoassay with outer membranes and by whole-cell immunofluorescence. Reactivity with native protein was considerably enhanced by incorporation of the adjuvant monophosphoryl lipid A into the liposome or micelle preparations. Recognition of the native protein was in a serotype-specific manner and was associated with the ability of the antisera to promote high levels of serotype-specific complement-mediated killing of meningococci. These results demonstrate that the PorB protein should be considered as a component of a vaccine designed to prevent serogroup B meningococcal infection.
Interaction ofNeisseria meningitidiswith Human Meningeal Cells Induces the Secretion of a Distinct Group of Chemotactic, Proinflammatory, and Growth-Factor Cytokines
Authors: Christodoulides Myron , Makepeace Benjamin L. , Partridge Kris A. , Kaur Davindaur , Fowler Mark I. , Weller Roy O. , Heckels John E. 
Published: July 2002

ABSTRACTThe interactions ofNeisseria meningitidiswith cells of the leptomeninges are pivotal events in the progression of bacterial leptomeningitis. An in vitro model based on the culture of human meningioma cells was used to investigate the role of the leptomeninges in the inflammatory response. Following challenge with meningococci, meningioma cells secreted specifically the proinflammatory cytokine interleukin-6 (IL-6), the CXC chemokine IL-8, the CC chemokines monocyte chemoattractant protein 1 (MCP-1) and regulated-upon-activation, normal-T-cell expressed and secreted protein (RANTES), and the cytokine growth factor granulocyte-macrophage colony-stimulating factor (GM-CSF). A temporal pattern of cytokine production was observed, with early secretion of IL-6, IL-8, and MCP-1 followed by later increases in RANTES and GM-CSF levels. IL-6 was induced equally by the interactions of piliated and nonpiliated meningococci, whereas lipopolysaccharide (LPS) had a minimal effect, suggesting that other, possibly secreted, bacterial components were responsible. Induction of IL-8 and MCP-1 also did not require adherence of bacteria to meningeal cells, but LPS was implicated. In contrast, efficient stimulation of RANTES by intact meningococci required pilus-mediated adherence, which served to deliver increased local concentrations of LPS onto the surface of meningeal cells. Secretion of GM-CSF was induced by pilus-mediated interactions but did not involve LPS. In addition, capsule expression had a specific inhibitory effect on GM-CSF secretion, which was not observed with IL-6, IL-8, MCP-1, or RANTES. Thus, the data demonstrate that cells of the leptomeninges are not inert but are active participants in the innate host response during leptomeningitis and that there is a complex relationship between expression of meningococcal components and cytokine induction.
Lipopolysaccharide-Binding Protein- and CD14-Dependent Activation of Mitogen-Activated Protein Kinase p38 by Lipopolysaccharide in Human Neutrophils Is Associated with Priming of Respiratory Burst
Authors: Yan Sen Rong , Al-Hertani Walla , Byers David , Bortolussi Robert 
Published: July 2002

ABSTRACTNeutrophil (PMN) functions can be primed for greatly increased oxidative radical release by exposure to certain agents such as lipopolysaccharide (LPS). Although a variety of signaling pathways involving both tyrosine kinases and mitogen-activated protein (MAP) kinases may be operative, the mechanisms of PMN priming are still not understood. We found that PMN priming was not achieved by treatment of cells with a very low concentration (5 ng/ml) of LPS unless additional “helper” factors were present in plasma (5%). Under these conditions, LPS induced tyrosine phosphorylation of a 38-kDa protein, which was coincident with the MAP kinase p38 action in this situation. LPS-mediated activation of p38 in human PMNs was dependent on the presence of LPS binding protein from plasma and CD14 on the surfaces of the cells. Phosphorylation of p38 was highly correlated with LPS priming of a formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMN respiratory burst. Treatment of PMN with the p38-specific inhibitor SB203580 significantly attenuated the respiratory burst in cells primed by LPS and stimulated by fMLP. These results suggest that the LPS signaling pathway leading to p38 activation may be an important mechanism in regulation of PMN priming. The mediator(s) linking CD14 to p38 involves proteins that are functionally sensitive to genistein but insensitive to tyrphostin AG126 and to Src- and Syk-family kinase, protein kinase C, and phosphatidylinositol 3-kinase inhibitors. Elucidating this pathway will provide insight into possible regulation of PMN priming by LPS.
Organization of the PlasmidcpeLocus inClostridium perfringensType A Isolates
Authors: Miyamoto Kazuaki , Chakrabarti Ganes , Morino Yosiharu , McClane Bruce A. 
Published: July 2002

ABSTRACTClostridium perfringenstype A isolates causing food poisoning have a chromosomal enterotoxin gene (cpe), whileC. perfringenstype A isolates responsible for non-food-borne human gastrointestinal diseases carry a plasmidcpegene. In the present study, the plasmidcpelocus of the type A non-food-borne-disease isolate F4969 was sequenced to design primers and probes for comparative PCR and Southern blot studies of thecpelocus in other type A isolates. Those analyses determined that the region upstream of the plasmidcpegene is highly conserved among type A isolates carrying acpeplasmid. The organization of the type A plasmidcpelocus was also found to be unique, as it contains IS1469sequences located similarly to those in the chromosomalcpelocus but lacks the IS1470sequences found upstream of IS1469in the chromosomalcpelocus. Instead of those upstream IS1470sequences, a partial open reading frame potentially encoding cytosine methylase (dcm) was identified upstream of IS1469in the plasmidcpelocus of all type A isolates tested. Similardcmsequences were also detected in severalcpe-negativeC. perfringensisolates carrying plasmids but not in type A isolates carrying a chromosomalcpegene. Contrary to previous reports, sequences homologous to IS1470, rather than IS1151, were found downstream of the plasmidcpegene in most type A isolates tested. Those IS1470-like sequences reside in about the same position but are oppositely oriented and defective relative to the IS1470sequences found downstream of the chromosomalcpegene. Collectively, these and previous results suggest that thecpeplasmid of many type A isolates originated from integration of acpe-containing genetic element near thedcmsequences of aC. perfringensplasmid. The similarity of the plasmidcpelocus in many type A isolates is consistent with horizontal transfer of a commoncpeplasmid amongC. perfringenstype A strains.
Identification of an Aggregative Adhesion Fimbria (AAF) Type III-Encoding Operon in Enteroaggregative
Escherichia coli
as a Sensitive Probe for Detecting the AAF-Encoding Operon Family
Authors: Bernier Christine , Gounon Pierre , Le Bouguénec Chantal 
Published: July 2002

ABSTRACT

Enteroaggregative
Escherichia coli
(EAEC) is recognized as an emerging cause of diarrhea in children and adults worldwide, and recent studies have implicated EAEC in persistent diarrhea in patients infected with human immunodeficiency virus (HIV). In this study, we identified aggregative adhesion fimbria type III (AAF-III) in isolate 55989, a typical EAEC strain. Analysis of the sequence of the plasmid-borne
agg-3
gene cluster encoding AAF-III showed this cluster to be closely related to the
agg
and
aaf
operons and to the
afa
operons carried by diffusely adherent pathogenic
E. coli
. We investigated the adhesion properties of a collection of 25 EAEC strains isolated from HIV-infected patients presenting with persistent diarrhea. We found that a minority of strains (36%) carried sequences similar to those of the
agg
and
aaf
operons, which encode AAF-I and AAF-II, respectively. We developed PCR assays specific for the
agg-3
operon. In our collection, the frequency of AAF-III strains was similar (12%) to that of AAF-I strains (16%) but higher than that of AAF-II isolates (0%). Differences between EAEC strains in terms of the virulence factors present render detection of these strains difficult with the available DNA probes. Based on comparison of the
agg
,
aaf
, and
agg-3
operons, we defined an AAF probe internal to the adhesion gene clusters and demonstrated that it was efficient for the identification of EAEC strains. We investigated 32 EAEC isolates, of which only 34.4% were detected with the classical CVD432 probe (detecting pAA virulence plasmids) whereas 65.6% were detected with the AAF probe.
Clostridium septicumAlpha-Toxin Is Active against the Parasitic ProtozoanToxoplasma gondiiand Targets Members of the SAG Family of Glycosylphosphatidylinositol-Anchored Surface Proteins
Authors: Wichroski Michael J. , Melton Jody A. , Donahue Carolyn G. , Tweten Rodney K. , Ward Gary E. 
Published: July 2002

ABSTRACTAs is the case with many other protozoan parasites, glycosylphosphatidylinositol (GPI)-anchored proteins dominate the surface ofToxoplasma gondiitachyzoites. The mechanisms by whichT. gondiiGPI-anchored proteins are synthesized and transported through the unusual triple-membrane structure of the parasite pellicle to the plasma membrane remain largely unknown. As a first step in developing tools to study these processes, we show here thatClostridium septicumalpha-toxin, a pore-forming toxin that targets GPI-anchored protein receptors on the surface of mammalian cells, is active againstT. gondiitachyzoites (50% effective concentration, 0.2 nM). Ultrastructural studies reveal that a tight physical connection between the plasma membrane and the underlying membranes of the inner membrane complex is locally disrupted by toxin treatment, resulting in a massive outward extension of the plasma membrane and ultimately lysis of the parasite. Toxin treatment also causes swelling of the parasite endoplasmic reticulum, providing the first direct evidence that alpha-toxin is a vacuolating toxin. Alpha-toxin binds to several parasite GPI-anchored proteins, including surface antigen 3 (SAG3) and SAG1. Interestingly, differences in the toxin-binding profiles between the virulent RH and avirulent P strain were observed. Alpha-toxin may prove to be a powerful experimental tool for molecular genetic analysis of GPI anchor biosynthesis and GPI-anchored protein trafficking inT. gondiiand other susceptible protozoa.
Tissue Tropism of Enteropathogenic
Escherichia coli
Strains Belonging to the O55 Serogroup
Authors: Fitzhenry R. J. , Reece S. , Trabulsi L. R. , Heuschkel R. , Murch S. , Thomson M. , Frankel G. , Phillips A. D. 
Published: July 2002

ABSTRACT

Four enteropathogenic
Escherichia coli
(EPEC) strains belonging to the O55 serogroup (G21 and G30 [both O55:H6], G35 [O55:H−], and G58 [O55:H7]) were tested for their tissue tropism by using human intestinal in vitro organ culture. Strains showed restricted adhesion with attaching-and-effacing activity to follicle-associated epithelium of Peyer's patches, with no apparent adhesion to duodenum or colon. G35 and G58 express intimin γ and show a similar tropism to intimin γ-expressing enterohemorrhagic
E. coli
(EHEC) O157:H7. However, strains G21 and G30 were unusual because they expressed intimin α and had a restricted tissue tropism of intimin γ phenotype. The amino acid sequence of the carboxy-terminal 280 amino acids of intimin from G21 was determined. Comparison with the prototype intimin α from strain E2348/69 (O127:H6) showed a single amino acid difference (corresponding to Val907 and Ala907 in the whole intimins). This mutation was reproduced by site-directed mutagenesis in an intimin α plasmid template, pCVD438, with the hypothesis that it may induce a change in tropism. However, when the mutated plasmid was placed in both EPEC and EHEC backgrounds, duodenal adhesion in a manner similar to strain E2348/69 was evident upon in vitro organ culture. Thus, additional factor(s) unrelated to intimin exist in the O55:H6 genome that influence human intestinal tissue tropism.
Characterization of Pit, a
Streptococcus pneumoniae
Iron Uptake ABC Transporter
Authors: Brown Jeremy S. , Gilliland Sarah M. , Ruiz-Albert Javier , Holden David W. 
Published: July 2002

ABSTRACT

Bacteria frequently have multiple mechanisms for acquiring iron, an essential micronutrient, from the environment. We have identified a four-gene
Streptococcus pneumoniae
operon, named
pit
, encoding proteins with similarity to components of a putative
Brachyspira hyodysenteriae
iron uptake ABC transporter, Bit. An
S. pneumoniae
strain containing a defined mutation in
pit
has impaired growth in medium containing the iron chelator ethylenediamine di-
o
-hydroxyphenylacetic acid, reduced sensitivity to the iron-dependent antibiotic streptonigrin, and impaired virulence in a mouse model of
S. pneumoniae
systemic infection. Furthermore, addition of a mutation in
pit
to a strain containing mutations in the two previously described
S. pneumoniae
iron uptake ABC transporters,
piu
and
pia
, resulted in a strain with impaired growth in two types of iron-deficient medium, a high degree of resistance to streptonigrin, and a reduced rate of iron uptake. Comparison of the susceptibilities to streptonigrin of the individual
pit
,
piu
, and
pia
mutant strains and comparison of the growth in iron-deficient medium and virulence of single and double mutant strains suggest that
pia
is the dominant iron transporter during in vitro and in vivo growth.
Defective Hyphal Induction of a
Candida albicans
Phosphatidylinositol 3-Phosphate 5-Kinase Null Mutant on Solid Media Does Not Lead to Decreased Virulence
Authors: Augsten Martin , Hübner Claudia , Nguyen Monika , Künkel Waldemar , Härtl Albert , Eck Raimund 
Published: July 2002

ABSTRACT

A phosphatidylinositol 3-phosphate [PI(3)P] 5-kinase gene (
CaFAB1
) of the most important human pathogenic yeast,
Candida albicans
, was cloned and sequenced. An open reading frame was detected which encodes a 2,369-amino-acid protein with a calculated molecular mass of 268 kDa and a relative isoelectric point of 6.76. This protein exhibits 38% overall amino acid sequence identity with
Saccharomyces cerevisiae
Fab1p. We localized the
CaFAB1
gene on chromosome R. To determine the influence of the PI(3)P 5-kinase CaFab1p on processes involved in
C. albicans
morphogenesis and pathogenicity, we sequentially disrupted both copies of the gene. Homozygous deletion of
C. albicans CaFAB1
resulted in a mutant strain which exhibited defects in morphogenesis. A
Cafab1
null mutant had enlarged vacuoles, an acidification defect, and increased generation times and was unable to form hyphae on different solid media. The sensitivities to hyperosmotic and high-temperature stresses, adherence, and virulence compared to those of wild-type strain SC5314 were not affected.
Structure-Function Analysis of Decay-Accelerating Factor: Identification of Residues Important for Binding of theEscherichia coliDr Adhesin and Complement Regulation
Authors: Hasan Rafia J. , Pawelczyk Edyta , Urvil Petri T. , Venkatarajan Mathura S. , Goluszko Pawel , Kur Jozef , Selvarangan Rangaraj , Nowicki Stella , Braun Werner A. , Nowicki Bogdan J. 
Published: July 2002

ABSTRACTDecay-accelerating factor (DAF), a complement regulatory protein, also serves as a receptor for Dr adhesin-bearingEscherichia coli.The repeat three of DAF was shown to be important in Dr adhesin binding and complement regulation. However, Dr adhesins do not bind to red blood cells with the rare polymorphism of DAF, designated Dr(a−); these cells contain a point mutation (Ser165-Leu) in DAF repeat three. In addition, monoclonal antibody IH4 specific against repeat three was shown to block both Dr adhesin binding and complement regulatory functions of DAF. Therefore, to identify residues important in binding of Dr adhesin and IH4 and in regulating complement, we mutated 11 amino acids—predominantly those in close proximity to Ser165 to alanine—and expressed these mutations in Chinese hamster ovary cells. To map the mutations, we built a homology model of repeat three based on the poxvirus complement inhibitory protein, using the EXDIS, DIAMOD, and FANTOM programs. We show that perhaps Ser155, and not Ser165, is the key amino acid that interacts with the Dr adhesin and amino acids Gly159, Tyr160, and Leu162 and also aids in binding Dr adhesin. The IH4 binding epitope contains residues Phe148, Ser155, and L171. Residues Phe123 and Phe148 at the interface of repeat 2-3, and also Phe154 in the repeat three cavity, were important for complement regulation. Our results show that residues affecting the tested functions are located on the same loop (148 to 171), at the same surface of repeat three, and that the Dr adhesin-binding and complement regulatory epitopes of DAF appear to be distinct and are ≈20 Å apart.
Identification and Characterization of a Novel Heme-Associated Cell Surface Protein Made by
Streptococcus pyogenes
Authors: Lei Benfang , Smoot Laura M. , Menning Heather M. , Voyich Jovanka M. , Kala Subbarao V. , Deleo Frank R. , Reid Sean D. , Musser James M. 
Published: July 2002

ABSTRACT

Analysis of the genome sequence of a serotype M1 group A
Streptococcus
(GAS) strain identified a gene encoding a previously undescribed putative cell surface protein. The gene was cloned from a serotype M1 strain, and the recombinant protein was overexpressed in
Escherichia coli
and purified to homogeneity. The purified protein was associated with heme in a 1:1 stoichiometry. This streptococcal heme-associated protein, designated Shp, was produced in vitro by GAS, located on the bacterial cell surface, and accessible to specific antibody raised against the purified recombinant protein. Mice inoculated subcutaneously with GAS and humans with invasive infections and pharyngitis caused by GAS seroconverted to Shp, indicating that Shp was produced in vivo. The blood of mice actively immunized with Shp had significantly higher bactericidal activity than the blood of unimmunized mice. The
shp
gene was cotranscribed with eight contiguous genes, including homologues of an ABC transporter involved in iron uptake in gram-negative bacteria. Our results indicate that Shp is a novel cell surface heme-associated protein.