bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation of Natural Killer Cells in Arthritis-Susceptible but Not Arthritis-Resistant Mouse Strains followingBorrelia burgdorferiInfection
Authors: Brown Charles R. , Reiner Steven L.
Published: December 2019

Infection of susceptible mouse strains withBorrelia burgdorferi, the agent of Lyme disease, results in the development of arthritis. Components of the innate immune system may be important mediators of this pathology. To investigate the potential role of NK cells in development of experimental Lyme arthritis, we examined their activation in vivo in both resistant and susceptible mouse strains. Following inoculation ofB. burgdorferiinto the footpad, lymph node NK cells from susceptible C3H/HeJ (C3H) mice produced more gamma interferon than NK cells from resistant DBA/2J mice. Lymph node cells from susceptible C3H and AKR mice also had increased ability to lyse YAC-1 target cells 2 days following infection. Antibody depletion of NK cells from susceptible mice, however, did not alter the development of arthritis followingB. burgdorferichallenge. In addition, NK cell depletion had little effect on spirochete burden. Thus, there is a marked activation of NK cells in susceptible mouse strains following infection. Although NK cells are not absolutely required for arthritis, events occurring prior to NK cell activation might be important in mediating pathology in experimental Lyme disease.
1,25-Dihydroxyvitamin D
3
Induces Nitric Oxide Synthase and Suppresses Growth of
Mycobacterium tuberculosis
in a Human Macrophage-Like Cell Line
Authors: Rockett Kirk A. , Brookes Roger , Udalova Irina , Vidal Vincent , Hill Adrian V. S. , Kwiatkowski Dominic
Published: December 2019

Inducible synthesis of nitric oxide (NO) by macrophages is an important mechanism of the host defense against intracellular infection in mice, but the evidence for significant levels of inducible NO production by human macrophages is controversial. Here we report that the human promyelocytic cell line HL-60, when differentiated to a macrophage-like phenotype, acquires the ability to produce substantial amounts of NO on stimulation with LPS or 1,25-dihydroxyvitamin D
3
(1,25-D
3
) in the absence of activating factors such as gamma interferon. Expression of the inducible nitric oxide synthase (NOS2) was confirmed by sequencing of the reverse transcription-PCR product from stimulated HL-60 cells. Kinetic studies after lipopolysaccharide stimulation show that NOS2 mRNA levels rise within 3 to 6 h, that conversion of [
14
C]arginine to [
14
C]citrulline is maximal at 5 to 6 days, and that levels of reactive nitrogen intermediates stabilize at around 20 μM at 7 to 8 days. We find that 1,25-D
3
acts to suppress the growth of
Mycobacterium tuberculosis
in these cells and that this effect is inhibited by
N
G
-monomethyl-
l
-arginine, suggesting that vitamin D-induced NO production may play a role in the host defense against human tuberculosis.
Diversity of Antigen Recognition by Serum Antibodies in Experimental Bovine Tuberculosis
Authors: Lyashchenko Konstantin P. , Pollock John M. , Colangeli Roberto , Gennaro Maria Laura
Published: December 2019

Tuberculosis in cattle remains a major zoonotic and economic problem in many countries. The standard diagnostic assay for bovine tuberculosis, the intradermal tuberculin test, has low accuracy. Therefore, alternative immunodiagnostic methods, such as serological assays, are needed for detection of infected animals. Development of an accurate serodiagnostic test requires a detailed understanding of the humoral immune responses during bovine tuberculosis and, in particular, identification of the key antigens ofMycobacterium bovisinvolved in antibody production. In this study, we characterized antibody responses in cattle experimentally infected withM. bovis. Sequential serum samples were collected every 3 to 4 weeks for up to 27 months postinfection. Circulating immunoglobulin G antibody levels were measured by an enzyme-linked immunosorbent assay using 12 highly purified recombinant proteins ofM. bovis. Six proteins, ESAT-6, 14-kDa protein, MPT63, MPT70, MPT51, and MPT32, were identified as major seroreactive antigens in bovine tuberculosis. A remarkable animal-to-animal variation of antigen recognition by serum antibodies was observed. Kinetic analyses of the antibody production to individual antigens during infection revealed that the heterogeneous antigen recognition profile changed markedly in a given infected animal as disease progressed.
Complement Activation in Relation to Capillary Leakage in Children with Septic Shock and Purpura
Authors: Hazelzet Jan A. , de Groot Ronald , van Mierlo Gerard , Joosten Koen F. M. , van der Voort Edwin , Eerenberg Anke , Suur Marja H. , Hop Wim C. J. , Hack C. Erik
Published: December 2019

To assess the relationship between capillary leakage and inflammatory mediators during sepsis, blood samples were taken on hospital admission, as well as 24 and 72 h later, from 52 children (median age, 3.3 years) with severe meningococcal sepsis, of whom 38 survived and 14 died. Parameters related to cytokines (interleukin 6 [IL-6] IL-8, plasma phospholipase A2, and C-reactive protein [CRP]), to neutrophil degranulation (elastase and lactoferrin), to complement activation (C3a, C3b/c, C4b/c, and C3- and C4-CRP complexes), and to complement regulation (functional and inactivated C1 inhibitor and C4BP) were determined. The degree of capillary leakage was derived from the amount of plasma infused and the severity of disease by assessing the pediatric risk of mortality (PRISM) score. Levels of IL-6, IL-8, C3b/c, C3-CRP complexes, and C4BP on admission, adjusted for the duration of skin lesions, were significantly different in survivors and nonsurvivors (C3b/c levels were on average 2.2 times higher in nonsurvivors, and C3-CRP levels were 1.9 times higher in survivors). Mortality was independently related to the levels of C3b/c and C3-CRP complexes. In agreement with this, levels of complement activation products correlated well with the PRISM score or capillary leakage. Thus, these data show that complement activation in patients with severe meningococcal sepsis is associated with a poor outcome and a more severe disease course. Further studies should reveal whether complement activation may be a target for therapeutical intervention in this disease.
Gene Discovery through Expressed Sequence Tag Sequencing inTrypanosoma cruzi
Authors: Verdun Ramiro E. , Di Paolo Nelson , Urmenyi Turan P. , Rondinelli Edson , Frasch Alberto C. C. , Sanchez Daniel O.
Published: December 2019

Analysis of expressed sequence tags (ESTs) constitutes a useful approach for gene identification that, in the case of human pathogens, might result in the identification of new targets for chemotherapy and vaccine development. As part of theTrypanosoma cruzigenome project, we have partially sequenced the 5′ ends of 1,949 clones to generate ESTs. The clones were randomly selected from a normalized CL Brener epimastigote cDNA library. A total of 14.6% of the clones were homologous to previously identifiedT. cruzigenes, while 18.4% had significant matches to genes from other organisms in the database. A total of 67% of the ESTs had no matches in the database, and thus, some of them might beT. cruzi-specific genes. Functional groups of those sequences with matches in the database were constructed according to their putative biological functions. The two largest categories were protein synthesis (23.3%) and cell surface molecules (10.8%). The information reported in this paper should be useful for researchers in the field to analyze genes and proteins of their own interest.
Impact of M49, Mrp, Enn, and C5a Peptidase Proteins on Colonization of the Mouse Oral Mucosa byStreptococcus pyogenes
Authors: Ji Yinduo , Schnitzler Norbert , DeMaster Eric , Cleary Patrick
Published: December 2019

Resistance to phagocytosis is a hallmark of virulentStreptococcus pyogenes(group A streptococcus). Surface-bound C5a peptidase reduces recruitment of phagocytes to the site of infection, and hyaluronic acid capsules and/or the M protein limit the uptake of streptococci. In this study the relative impact of M and M-like proteins and the C5a peptidase on the virulence of a serotype M49 strain was assessed. The capacities of isogenic strains with an insertion mutation inemm49; with a deletion mutation inscpA49(C5a peptidase gene); and with a deletion that removes all three M-like genes,mrp49,emm49, andenn49, to colonize mice and resist phagocytosis were compared. Experiments confirmed results obtained in an earlier study, which showed that the M49 protein was not required for in vitro resistance to phagocytosis, and also showed that the M protein was not required for colonization of mice. Failure to produce all three M-like proteins, M49, Mrp, and Enn49, significantly reduced the ability of these streptococci to resist phagocytosis in vitro but did not significantly alter the persistence of streptococci on the oral mucosa. In vitro experiments indicate that M+streptococci are phagocytized by polymorphonuclear leukocytes that have been activated with phorbol-12-myristate 13-acetate or recombinant human C5a. This observation may explain the finding that expression of M49 protein is not essential for short-term colonization of the mouse oral mucosa.
Murine Immune Responses toNeisseria meningitidisGroup C Capsular Polysaccharide and a Thymus-Dependent Toxoid Conjugate Vaccine
Authors: Rubinstein Leonard J. , García-Ojeda Pablo A. , Michon Francis , Jennings Harold J. , Stein Kathryn E.
Published: December 2019

The polysaccharide (PS) capsules of many pathogenic bacteria are poor immunogens in infants and young children as a result of the delayed response to PS antigens during ontogeny. The development of polysaccharide-protein conjugate vaccines forHaemophilus influenzaetype b, which have proven to be efficacious in this age group, has led to active development by a number of investigators of conjugate vaccines for other diseases. We describe here the response of several mouse strains to the capsular PS ofNeisseria meningitidisgroup C (MCPS) conjugated to tetanus toxoid (MCPS-TT) and the same response in BALB/c mice as a model of the immune consequences of conjugate vaccine immunization. The use of a conjugate vaccine results in a shift in the isotype elicited in response to the MCPS, from immunoglobulin M (IgM) and IgG3 to primarily IgG1. A response to MCPS-TT is seen even among mouse strains which respond poorly to MCPS itself, emphasizing the importance of a strain survey when choosing a mouse model for a vaccine. The marked increase in IgG1 antibody titer was accompanied by a large increase in bactericidal activity of sera from these animals. Animals primed with the conjugate vaccine demonstrated a booster response after secondary immunization with either the MCPS or the conjugate. The ability to produce a boosted IgG1 anti-MCPS response to the MCPS can be transferred to adoptive recipients by B cells alone from mice primed with MCPS-TT but not mice primed with MCPS alone. These data indicate that in BALB/c mice a single immunization with MCPS-TT is sufficient to induce a shift to IgG1 and generate a memory B-cell population that does not require T cells for boosting.
SCID/NCr Mice Naturally Infected with
Helicobacter hepaticus
Develop Progressive Hepatitis, Proliferative Typhlitis, and Colitis
Authors: Li Xiantang , Fox James G. , Whary Mark T. , Yan Lili , Shames Ben , Zhao Zhibao
Published: December 2019

Hepatitis, proliferative typhlitis, and colitis were characterized in young adult and older SCID/NCr mice naturally infected with
Helicobacter hepaticus
. Liver lesions consisted of Kupffer, Ito, and oval cell hyperplasia along with multifocal to coalescing coagulative hepatocyte necrosis. Numerous Warthin-Starry-positive bacteria were observed in the parenchyma, and there were minimal to mild accumulations of monocytic cells and neutrophils. Proliferative typhlitis was characterized by moderate to marked mucosal epithelial cell hyperplasia with mild monocytic and neutrophilic infiltration. Minimal to mild colitis with mucosal epithelial cell hyperplasia of the colon was most marked in older mice. Comparable gastrointestinal lesions were not observed in uninfected control SCID/NCr mice.
H. hepaticus
was cultured from fetal viscera of 2 of 11 pups sampled late in gestation from infected SCID/NCr females, suggesting transplacental infection of
H. hepaticus
. As expected, most of the naturally infected SCID/NCr mice had no serum immunoglobulin G response against
H. hepaticus
. These findings contrast with those in infected immunocompetent A/JCr mice, which develop a significant immune response to
H. hepaticus
associated with prominent multifocal mononuclear cell infiltrates in the liver, with only rare bacteria observable at the periphery of inflammatory foci or in the biliary canaliculi. The results demonstrate that chronic inflammatory and proliferative lesions simultaneously affecting the liver, cecum, and colon are associated with natural infection of SCID/NCr mice with
H. hepaticus
and that lesions are progressive with age. Concurrent infection with
H. hepaticus
may confound studies that have been attributed to similar lesions due to other experimental manipulations of SCID/NCr mice.
Identification of the Perosamine Synthetase Gene ofBrucella melitensis16M and Involvement of Lipopolysaccharide O Side Chain inBrucellaSurvival in Mice and in Macrophages
Authors: Godfroid Fabrice , Taminiau Bernard , Danese Isabelle , Denoel Philippe , Tibor Anne , Weynants Vincent , Cloeckaert Axel , Godfroid Jacques , Letesson Jean-Jacques
Published: December 2019

Brucellaorganisms are facultative intracellular bacteria that may infect many species of animals as well as humans. The smooth lipopolysaccharide (S-LPS) has been reported to be an important virulence factor of these organisms, but the genetic basis of expression of the S-LPS O antigen has not yet been described. Likewise, the role of the O side chain of S-LPS in the survival ofBrucellahas not been clearly defined. A mini-Tn5transposon mutant library ofBrucella melitensis16M was screened by enzyme-linked immunosorbent assay (ELISA) with monoclonal antibodies (MAbs) directed against the O side chain ofBrucella. One mutant, designated B3B2, failed to express any O side chain as confirmed by ELISA, Western blot analysis, and colony coloration with crystal violet. Nucleotide sequence analysis demonstrated that the transposon disrupted an open reading frame with significant homology to the putative perosamine synthetase genes ofVibrio choleraeO1 andEscherichia coliO157:H7. The low G+C content of this DNA region suggests that this gene may have originated from a species other than aBrucellasp. The survival ofB. melitensismutant strain B3B2 in the mouse model and in bovine macrophages was examined. The results suggested that S-LPS or, more precisely, its O side chain is essential for survival in mice but not in macrophages.
Nitric Oxide Synthase Expression in Macrophages ofHistoplasma capsulatum-Infected Mice Is Associated with Splenocyte Apoptosis and Unresponsiveness
Authors: Wu-Hsieh Betty A. , Chen Wen , Lee Hsin-Ju
Published: December 2019

Splenic macrophages fromHistoplasma capsulatum-infected mice express inducible nitric oxide synthase (iNOS), and the iNOS expression correlates with severity of the infection. We examined whether production of NO is responsible for apoptosis and the anti-lymphoproliferative response of splenocytes from mice infected withH. capsulatum. In situ terminal deoxynucleotidyl transferase nick end labeling revealed apoptotic nuclei in cryosections of spleen from infected but not normal mice. Splenocytes of infected mice were unresponsive to stimulation by either concanavalin A or heat-killedH. capsulatumyeast cells. Splenocyte responsiveness was restored by addition to the medium ofNG-monomethyl-l-arginine, a known inhibitor of NO production. The proliferative response of splenocytes from infected mice was also restored by depletion of macrophages or by replacement with macrophages from normal mice. In addition, expression of iNOS returned to its basal level when the animals had recovered from infection. These results suggest that suppressor cell activity of macrophages is associated with production of NO, which also appears to be an effector molecule for apoptosis of cultured splenocytes from infected mice.
Coxiella burnetiiInduces Reorganization of the Actin Cytoskeleton in Human Monocytes
Authors: Meconi Sonia , Jacomo Véronique , Boquet Patrice , Raoult Didier , Mege Jean-Louis , Capo Christian
Published: December 2019

Coxiella burnetii, an obligate intracellular bacterium which survives in myeloid cells, causes Q fever in humans. We previously demonstrated that virulentC. burnetiiorganisms are poorly internalized by monocytes compared to avirulent variants. We hypothesized that a differential mobilization of the actin cytoskeleton may account for this distinct phagocytic behavior. Scanning electron microscopy demonstrated that virulentC. burnetiistimulated profound and polymorphic changes in the morphology of THP-1 monocytes, consisting of membrane protrusions and polarized projections. These changes were transient, requiring 5 min to reach their maximum extent and vanishing after 60 min of incubation. In contrast, avirulent variants ofC. burnetiidid not induce any significant changes in cell morphology. The distribution of filamentous actin (F-actin) was then studied with a specific probe, bodipy phallacidin. VirulentC. burnetiiinduced a profound and transient reorganization of F-actin, accompanied by an increase in the F-actin content of THP-1 cells. F-actin was colocalized with myosin in cell protrusions, suggesting that actin polymerization and the tension of actin-myosin filaments play a role inC. burnetii-induced morphological changes. In addition, contact between the cell and the bacterium seems to be necessary to induce cytoskeleton reorganization. Bacterial supernatants did not stimulate actin remodeling, and virulentC. burnetiiorganisms were found in close apposition with F-actin protrusions. The manipulation of the actin cytoskeleton byC. burnetiimay therefore play a critical role in the internalization strategy of this bacterium.
Diversity in Protein Synthesis and Viability of
Helicobacter pylori
Coccoid Forms in Response to Various Stimuli
Authors: Mizoguchi Hiromoto , Fujioka Toshio , Kishi Kenji , Nishizono Akira , Kodama Reiji , Nasu Masaru
Published: December 2019

The viability of the coccoid forms of
Helicobacter pylori
was evaluated by assessing protein synthesis. Metabolic labeling studies showed the synthesis of proteins and the specific protein profiles of
H. pylori
coccoids produced under various conditions. Harsh conditions such as aerobiosis and starvation (lack of horse serum) in the culture did not affect the synthesis of proteins in the coccoids. Lowering of the pH to that of gastric secretions induced expression of several proteins in the coccoids. However, the coccoids produced under prolonged microaerobic conditions exhibited a profile of acid stress-induced protein expression different from that induced by aerobiosis or starvation. Our data suggest that coccoid
H. pylori
exhibits diversity in viability following exposure to different stresses and that the response to acid stress of coccoid
H. pylori
could be involved in infection of the host stomach.
The Lipopolysaccharide of
Bordetella bronchiseptica
Acts as a Protective Shield against Antimicrobial Peptides
Authors: Banemann Andreas , Deppisch Heike , Gross Roy
Published: December 2019

Resistance profiles of the two
Bordetella
species
B. bronchiseptica
and
B. pertussis
against various antimicrobial peptides were determined in liquid survival and agar diffusion assays.
B. bronchiseptica
exhibited significantly higher resistance against all tested peptides than
B. pertussis
. The most powerful agents acting on
B. bronchiseptica
were, in the order of their killing efficiencies, cecropin P > cecropin B > magainin-II-amide > protamine > melittin. Interestingly, for
B. bronchiseptica
, the resistance level was significantly affected by phase variation, as a
bvgS
deletion derivative showed an increased sensitivity to these peptides. Tn
5
-induced protamine-sensitive
B. bronchiseptica
mutants, which were found to be very susceptible to most of the cationic peptides, were isolated. In two of these mutants, the genetic loci inactivated by transposon insertion were identified as containing genes highly homologous to the
wlbA
and
wlbL
genes of
B. pertussis
that are involved in the biosynthesis of lipopolysaccharide (LPS). In agreement with this finding, the two peptide-sensitive mutants revealed structural changes in the LPS, resulting in the loss of the O-specific side chains and the prevalence of the LPS core structure. This demonstrates that LPS plays a major role in the resistance of
B. bronchiseptica
against the action of antimicrobial peptides and suggests that
B. pertussis
is much more susceptible to these peptides due to the lack of the highly charged O-specific sugar side chains.
Systemic and Mucosal Immune Responses after Intranasal Administration of RecombinantMycobacterium bovisBacillus Calmette-Guérin Expressing GlutathioneS-Transferase fromSchistosoma haematobium
Authors: Kremer Laurent , Dupré Loïc , Riveau Gilles , Capron André , Locht Camille
Published: December 2019

A major goal of current vaccine development is the induction of strong immune responses against protective antigens delivered by mucosal routes. One of the most promising approaches in that respect relies on the use of live recombinant vaccine carriers. In this study,Mycobacterium bovisBCG was engineered to produce an intracellular glutathioneS-transferase fromSchistosoma haematobium(Sh28GST). The gene encoding Sh28GST was placed under the control of the mycobacterialhsp60promoter on a replicative shuttle plasmid containing a mercury resistance operon as the only selectable marker. The recombinant Sh28GST produced in BCG bound glutathione and expressed enzymatic activity, indicating that its active site was properly folded. Both intraperitoneal and intranasal immunizations of BALB/c mice with the recombinant BCG resulted in strong anti-Sh28GST antibody responses, which were enhanced by a boost. Mice immunized intranasally produced a mixed response with the production of Sh28GST-specific immunoglobulin G1 (IgG1), IgG2a, IgG2b, and IgA in the serum. In addition, high levels of anti-Sh28GST IgA were also found in the bronchoalveolar lavage fluids, demonstrating that intranasal delivery of the recombinant BCG was able to induce long-lasting secretory and systemic immune responses to antigens expressed intracellularly. Surprisingly, intranasal immunization with the BCG producing the Sh28GST induced a much stronger specific humoral response than intranasal immunization with BCG producing the glutathioneS-transferase fromSchistosoma mansoni, although the two antigens have over 90% identity. This difference was not observed after intraperitoneal administration.
Mycobacterial Dose Defines the Th1/Th2 Nature of the Immune Response Independently of Whether Immunization Is Administered by the Intravenous, Subcutaneous, or Intradermal Route
Authors: Power Carl A. , Wei Guojian , Bretscher Peter A.
Published: December 2019

It is believed that cell-mediated immunity alone can containMycobacterium tuberculosis, the pathogen responsible for tuberculosis. The induction of antibody, or of a mixed cell-mediated/humoral response, is associated with tuberculous disease. It is therefore important to determine the conditions of immunization with bacille Calmette Guérin (BCG), the attenuated strain ofMycobacterium bovisused to vaccinate humans against tuberculosis, that optimally induces an exclusive cell-mediated, Th1 response. Such a determination will then allow an assessment of whether the generation of such an exclusive Th1 response results in the generation of a Th1 imprint against mycobacteria. This Th1 imprint would ensure that the Th1 response is predominant following any challenge. We therefore tested the proposition that the dose of mycobacteria used for immunization generally determines the Th1/Th2 nature of the ensuing response. Our results demonstrate that relatively low doses lead to an almost exclusive cell-mediated, Th1 response, while higher doses induce a mixed Th1/Th2 response. Furthermore, the dependence on dose is independent of whether BCG is administered intravenously, subcutaneously, or intradermally. The implications of our findings to understanding how different classes of immunity are induced, to the epidemiology of tuberculosis, and to the design of effective vaccination strategies are discussed.
Expression of Plasminogen Activator Pla of
Yersinia pestis
Enhances Bacterial Attachment to the Mammalian Extracellular Matrix
Authors: Lähteenmäki Kaarina , Virkola Ritva , Sarén Anne , Emödy Levente , Korhonen Timo K.
Published: December 2019

The effect of the plasminogen activator Pla of
Yersinia pestis
on the adhesiveness of bacteria to the mammalian extracellular matrix was determined.
Y. pestis
KIM D27 harbors the 9.5-kb plasmid pPCP1, encoding Pla and pesticin; the strain efficiently adhered to the reconstituted basement membrane preparation Matrigel, to the extracellular matrix prepared from human lung NCI-H292 epithelial cells, as well as to immobilized laminin. The isogenic strain
Y. pestis
KIM D34 lacking pPCP1 exhibited lower adhesiveness to both matrix preparations and to laminin. Both strains showed weak adherence to type I, IV, and V collagens as well as to human plasma and cellular fibronectin. The Pla-expressing recombinant
Escherichia coli
LE392(pC4006) exhibited specific adhesiveness to both extracellular matrix preparations as well as to laminin. The Pla-expressing strains showed a low-affinity adherence to another basement membrane component, heparan sulfate proteoglycan, but not to chondroitin sulfate proteoglycan. The degradation of radiolabeled laminin, heparan sulfate proteoglycan, or human lung extracellular matrix by the Pla-expressing recombinant
E. coli
required the presence of plasminogen, and degradation was inhibited by the plasmin inhibitors aprotinin and α2-antiplasmin. Our results indicate a function of Pla in enhancing bacterial adhesion to extracellular matrices.
Y. pestis
also exhibits a low level of Pla-independent adhesiveness to extracellular matrices.
Relationship between Hydroxy Fatty Acids and Prostaglandin E2in Gingival Tissue
Authors: Nichols Frank , Maraj Baliram
Published: December 2019

Bacterial hydroxy fatty acids and alpha-hydroxy fatty acids have been demonstrated in complex lipid extracts of subgingival plaque and gingival tissue. However, little is known about the relationship between these hydroxy fatty acids in plaque and gingival tissues or the significance of these complex lipids in promoting inflammatory periodontal disease. The present study determined the percentages of ester-linked and amide-linked hydroxy fatty acids in complex lipids recovered from plaque and gingival tissue samples and the relationship between bacterial hydroxy fatty acids and alpha-hydroxy fatty acids in the lipid extracts. To evaluate a potential role for these hydroxy fatty acids in inflammatory periodontal disease, gingival tissue samples were examined for a relationship between prostaglandin E2(PGE2) and hydroxy fatty acids recovered in gingival lipid. This investigation demonstrated that alpha-hydroxy fatty acids are only ester linked in plaque lipids but are largely amide linked in gingival tissue lipids. Furthermore, the level of alpha-hydroxy fatty acid in gingival lipid is directly related to the level of the bacterial hydroxy fatty acid 3-OHiso-branched C17:0(3-OH iC17:0) in the same lipid extract. However, the relationship between hydroxy fatty acids in gingival lipids does not parallel the fatty acid relationship observed in plaque lipids. Finally, alpha-hydroxy fatty acid levels in gingival tissue lipids correlate directly with the recovery of PGE2in the same tissue samples. These results demonstrate that alpha-hydroxy fatty acid levels in gingival lipids are directly related to both 3-OH iC17:0bacterial lipid levels and PGE2levels. These results indicate that in periodontal tissues there are unusual host-parasite interactions involving penetration of bacterial lipid in association with an altered gingival lipid metabolism and prostaglandin synthesis.
Estimation of Group B Streptococcus Type III Polysaccharide-Specific Antibody Concentrations in Human Sera Is Antigen Dependent
Authors: Bhushan Reva , Anthony Bascom F. , Frasch Carl E.
Published: December 2019

The presence of immunoglobulin G (IgG) antibodies against group B streptococcus (GBS) type III polysaccharide (PS) has been correlated with protection against GBS disease. The GBS type III PS is structurally similar to the pneumococcal type 14 PS, differing only in the presence of sialic acid residues. Four different preparations of GBS type III PS were evaluated for their specificity in enzyme-linked immunosorbent assay (ELISA): free PS, free PS mixed with methylated human serum albumin (mHSA), PS conjugated to biotin and PS conjugated to human serum albumin. Three groups of human sera were used to evaluate these PS preparations: sera from recipients of a GBS PS vaccine, sera from women receiving a GBS type III PS-tetanus toxoid conjugate vaccine, and sera from nonimmunized healthy women of childbearing age. Estimated antibody concentrations were different depending on the PS preparation used. Using any of the four preparations, we were able to measure ≤0.05 μg of IgG antibody to the GBS type III PS per ml. The specificity of the assay was determined by competitive inhibition with homologous and heterologous PS. The pneumococcal type 14 PS did not inhibit binding of antibody to the native GBS type III PS in sera from adults receiving the GBS PS vaccine or in sera from nonimmunized adults (except serum G9). The pneumococcal type 14 PS inhibited 50% in sera from recipients of GBS type III conjugate vaccine and in serum G9 when GBS type III PS conjugated to biotin or to HSA was used as antigen in ELISA. These data show that free GBS type III PS or PS mixed with mHSA is a sensitive and specific antigen for ELISA and that conjugation can alter the antigenic specificity of a PS.
Specific-Antibody-Secreting Cells in the Rectums and Genital Tracts of Nonhuman Primates following Vaccination
Authors: Eriksson Kristina , Quiding-Järbrink Marianne , Osek Jacek , Möller Åke , Björk Stellan , Holmgren Jan , Czerkinsky Cecil
Published: December 2019

To determine optimal strategies to induce specific-antibody-secreting cells (specific ASC) in the rectal and vaginal mucosae, we immunized monkeys with a prototype mucosal immunogen, cholera toxin (CT), given locally or via gastric or parenteral administration. Repeated rectal or vaginal CT immunizations induced strong mucosal and systemic ASC responses. The mucosal responses were, however, confined to the immunization sites and comprised high levels of both specific antitoxin immunoglobulin A (IgA) and IgG. Large numbers of specific IgA and IgG ASC were detected in cell suspensions from dissociated genital and rectal tissues, demonstrating local accumulation of effector B cells at these sites. Intragastric immunization with CT did not per se give rise to cervicovaginal or rectal ASC responses but did prime for a rectal IgA ASC response to local booster immunization. Both rectal and vaginal immunizations also induced circulating blood IgG ASC and IgA ASC. In conclusion, these results show that local administration of antigen to the rectal or vaginal mucosa results in higher ASC responses than systemic or distant mucosal delivery. Furthermore, both the vaginal and the rectal mucosae can serve as inductive sites for systemic ASC responses. These observations should be relevant to the development of vaccines against sexually transmitted diseases such as that caused by human immunodeficiency virus.
Streptococcus sanguis-Induced Platelet Clotting in Rabbits and Hemodynamic and Cardiopulmonary Consequences
Authors: Meyer Maurice W. , Gong Ke , Herzberg Mark C.
Published: December 2019

By mimicking hemostatic structural domains of collagen,Streptococcus sanguis(aggregation-positive phenotype; Agg+) induces platelets to aggregate in vitro. To test the hypothesis that aggregation occurs in vivo,S. sanguis(Agg+or Agg−suspension) was infused intravenously into rabbits. The extent of hemodynamic and cardiopulmonary changes and the fate of circulating platelets were Agg+strain dose dependent. Within 45 to 50 s of the start of infusion, 40 × 108CFU of the Agg+strain caused increased blood pressure. Thirty seconds after infusion, other changes occurred. Intermittent electrocardiographic abnormalities (13 of 15 rabbits), ST-segment depression (10 of 15 rabbits), and preventricular contractions (7 of 15 rabbits) manifested at 3 to 7 min, with frequencies dose dependent. Respiratory rate and cardiac contractility increased during this phase. Blood catecholamine concentration, thrombocytopenia, accumulation of111Indium-labeled platelets in the lungs, and ventricular axis deviation also showed dose dependency. Rabbits were unaffected by inoculation of an Agg−strain. Therefore, Agg+S. sanguisinduced platelet aggregation in vitro. Platelet clots caused hemodynamic changes, acute pulmonary hypertension, and cardiac abnormalities, including ischemia.
Characterization of Human Immunoglobulin (Ig) Isotype and IgG Subclass Response to
Bartonella henselae
Infection
Authors: McGill Svena L. , Regnery Russell L. , Karem Kevin L.
Published: December 2019

Serologic parameters of cat scratch disease (CSD) were evaluated by Western blot analysis. Sera from patients with serologically confirmed CSD antigen were screened for immunoglobulin (Ig) isotype-specific as well as IgG subclass-specific reactivity against
Bartonella henselae
whole-cell antigen.
Bartonella
-negative control sera were used to determine baseline antibody activity. Heterogeneous
B. henselae
-specific IgG reactivity with numerous protein bands, ranging from >150 to <17 kDa, was observed. Though individual banding patterns were variable, one approximately 83-kDa
B. henselae
protein (Bh83) was immunoreactive with all CSD sera tested, suggesting it is a conserved antigen during infection. Bh83 was not recognized by reference human antisera against
Rickettsia rickettsii
,
Chlamydia
group positive,
Treponema pallidum
,
Orientia tsutsugamushi
,
Fransciscella tularensis
,
Ehrlichia chaffeensis
,
Mycoplasma pneumoniae
, and
Escherichia coli
, although other cross-reactive proteins were evident. Significantly, CSD sera failed to recognize the 83-kDa protein when tested against
Bartonella quintana
antigen, though sera from
B. quintana
-infected patients did react to Bh83. This cross-reactivity suggests epitope conservation during infection with
B. henselae
or
B. quintana
. Western blot analysis further revealed similar banding patterns when
B. henselae
was reacted against the Ig isotypes IgG and IgG
1
and both secretory and alpha chains of IgA. Neither IgM nor IgE reacted significantly to
Bartonella
antigen by our Western blot analysis. Dissection of the antibody response at the IgG subclass level indicated that prominent antigen recognition was limited to IgG
1
. These observations provide insight into induced immunity during CSD and provide evidence for conserved epitope expression during infection with
B. henselae
or
B. quintana
.
Filamentous Hemagglutinin ofBordetella bronchisepticaIs Required for Efficient Establishment of Tracheal Colonization
Authors: Cotter Peggy A. , Yuk Ming H. , Mattoo Seema , Akerley Brian J. , Boschwitz Jeff , Relman David A. , Miller Jeff F.
Published: December 2019

Adherence to ciliated respiratory epithelial cells is considered a critical early step inBordetellapathogenesis. ForBordetella pertussis, the etiologic agent of whooping cough, several factors have been shown to mediate adherence to cells and cell lines in vitro. These putative adhesins include filamentous hemagglutinin (FHA), fimbriae, pertactin, and pertussis toxin. Determining the precise roles of each of these factors in vivo, however, has been difficult, due in part to the lack of natural-host animal models for use withB. pertussis. Using the closely related speciesBordetella bronchiseptica, and by constructing both deletion mutation and ectopic expression mutants, we have shown that FHA is both necessary and sufficient for mediating adherence to a rat lung epithelial (L2) cell line. Using a rat model of respiratory infection, we have shown that FHA is absolutely required, but not sufficient, for tracheal colonization in healthy, unanesthetized animals. FHA was not required for initial tracheal colonization in anesthetized animals, however, suggesting that its role in establishment may be dedicated to overcoming the clearance action of the mucociliary escalator.
The (α2→8)-Linked Polysialic Acid Capsule and Lipooligosaccharide Structure Both Contribute to the Ability of Serogroup BNeisseria meningitidisTo Resist the Bactericidal Activity of Normal Human Serum
Authors: Kahler C. M. , Martin L. E. , Shih G. C. , Rahman M. M. , Carlson R. W. , Stephens D. S.
Published: December 2019

The molecular basis for the resistance of serogroup BNeisseria meningitidisto the bactericidal activity of normal human sera (NHS) was examined with a NHS-resistant, invasive serogroup B meningococcal isolate and genetically and structurally defined capsule-, lipooligosaccharide (LOS)-, and sialylation-altered mutants of the wild-type strain. Expression of the (α2→8)-linked polysialic acid serogroup B capsule was essential for meningococcal resistance to NHS. The very NHS-sensitive phenotype of acapsular mutants (99.9 to 100% killed in 10, 25, and 50% NHS) was not rescued by complete LOS sialylation or changes in LOS structure. However, expression of the capsule was necessary but not sufficient for a fully NHS-resistant phenotype. In an encapsulated background, loss of LOS sialylation by interrupting the α2,3 sialyltransferase gene,lst, increased sensitivity to 50% NHS. In contrast, replacement of the lacto-N-neotetraose α-chain (Galβ1-4GlcNAcβ1-3Galβ1-4Glc) with glucose extensions (GlcN) in agalEmutant resulted in a strain resistant to killing by 50% NHS at all time points. Encapsulated meningococci expressing a Hep2(GlcNAc)→KDO2→lipid A LOS without an α-chain demonstrated enhanced sensitivity to 50% NHS (98% killed at 30 min) mediated through the antibody-dependent classical complement pathway. Encapsulated LOS mutants expressing truncated Hep2→KDO2→lipid A and KDO2→lipid A structures were also sensitive to 50% NHS (98 to 100% killed at 30 min) but, unlike the wild-type strain and mutants with larger oligosaccharide structures, they were killed by hypogammaglobulinemic sera. These data indicate that encapsulation is essential but that the LOS structure contributes to the ability of serogroup BN. meningitidisto resist the bactericidal activity of NHS.
Filarial Nematode Parasites Secrete a Homologue of the Human Cytokine Macrophage Migration Inhibitory Factor
Authors: Pastrana Diana V. , Raghavan Nithyakalyani , FitzGerald Peter , Eisinger Stephen W. , Metz Christine , Bucala Richard , Schleimer Robert P. , Bickel Carol , Scott Alan L.
Published: December 2019

Filarial nematode parasites establish long-term chronic infections in the context of an antiparasite immunity that is strongly biased toward a Th2 response. The mechanisms that lead to this Th2 bias toward filarial antigens are not clear, but one possibility is that the parasites produce molecules that have the capacity to proactively modify their immunological environment. Here we report that filarial parasites of humans secrete a homologue of the human proinflammatory cytokine macrophage migration inhibitory factor (MIF) that has the capability of modifying the activity of human monocytes/macrophages. A cDNA clone isolated from aBrugia malayiinfective-stage larva expression library encoded a 12.5-kDa protein product (Bm-MIF) with 42% identity to human and murine MIF. MIF homologues were also found to be expressed in the related filarial speciesWuchereria bancroftiandOnchocerca volvulus.Bm-mifwas transcribed by adult and larval parasites, and the protein product was found in somatic extracts and in the parasite’s excretory-secretory products. Immunohistocytochemistry revealed thatBm-MIF was localized to cells of the hypodermis/lateral chord, the uterine wall, and larvae developing in utero. Unexpectedly, the activities of recombinantBm-MIF and human MIF on human monocytes/macrophages were found to be similar. When placed with monocytes/macrophages in a cell migration assay,Bm-MIF inhibited random migration. When placed away from cells,Bm-MIF induced an increase in monocyte/macrophage migration that was specifically inhibited by neutralizing anti-Bm-MIF antibodies.Bm-MIF is the first demonstration that helminth parasites produce cytokine homologues that have the potential to modify host immune responses to promote parasite survival.
Local Cytokine Response inHelicobacter pylori-Infected Subjects
Authors: Lindholm C. , Quiding-Järbrink M. , Lönroth H. , Hamlet A. , Svennerholm A.-M.
Published: December 2019

The host immune response toHelicobacter pyloriinfection might be of importance with regard to the outcome of infection by this organism, e.g., to explain why only a proportion of infected subjects develop peptic ulcers. In this study we have analyzed the local response of different cytokines—i.e., the proinflammatory interleukin-1β, (IL-1β), IL-6, tumor necrosis factor alpha, and IL-8; the immunoregulatory gamma interferon (IFN-γ); and IL-4; and the anti-inflammatory transforming growth factor beta (TGF-β)—in antral biopsy specimens fromH. pylori-infected duodenal ulcer (DU) patients and asymptomatic (AS) carriers (i.e., with chronic gastritis only). For comparison, biopsy specimens from uninfected healthy individuals were also analyzed. An immunohistochemical technique was used to allow quantification of the cytokine responses as well as identification of the cell types associated with the cytokine expression. We found that the levels of all of the studied cytokines except IL-4 were increased in theH. pylori-infected subjects compared to the levels in the healthy individuals. Our results indicate that the antral cytokine response is of the Th1type since IFN-γ, but not IL-4, was up-regulated both inH. pylori-infected DU patients and in AS carriers. However, there were no significant differences in either proinflammatory or immunoregulatory cytokine levels whenH. pylori-infected subjects with and without peptic ulcers were compared. Some of the cytokines, particularly IL-1β and TGF-β, were also found in the gastric mucosae of healthy, uninfected subjects. We also showed that the gastric epithelium contributes substantially to the antral cytokine response of the proinflammatory cytokines IL-1β and IL-6 in addition to IL-8.
Identification of a
Chlamydia trachomatis
Serovar E Urogenital Isolate Which Lacks the Cryptic Plasmid
Authors: Stothard Diane R. , Williams James A. , Van Der Pol Barbara , Jones Robert B.
Published: December 2019

Our laboratory recently recovered
Chlamydia trachomatis
in tissue culture from a urogenital specimen which tested negative by commercial plasmid-based PCR. Immunotyping and
omp1
sequencing identified the isolate as a serovar E isolate. Further investigation by PCR and Southern hybridization indicated that this isolate lacks the chlamydial cryptic plasmid.
Sialic Acid-Dependent Recognition of Laminin by
Penicillium marneffei
Conidia
Authors: Hamilton A. J. , Jeavons L. , Youngchim S. , Vanittanakom N. , Hay R. J.
Published: December 2019

Immunofluorescence microscopy demonstrated that laminin bound to the surface of
Penicillium marneffei
conidia. Attachment of
P. marneffei
conidia in an adherence assay was inhibited by soluble laminin and anti-laminin antibody.
N
-Acetylneuraminic acid abolished adherence, indicating an interaction mediated by a sialic acid-specific lectin.
Phagocytic and Tumor Necrosis Factor Alpha Response of Human Mast Cells following Exposure to Gram-Negative and Gram-Positive Bacteria
Authors: Arock Michel , Ross Elaine , Lai-Kuen René , Averlant Geneviève , Gao Zhimin , Abraham Soman N.
Published: December 2019

Recent studies have implicated rodent mast cells in the innate immune response to infectious bacteria. We report that cord blood-derived human mast cells (CBHMC) obtained from culture of cord blood progenitors phagocytozed and killed various gram-negative and gram-positive bacteria and simultaneously released considerable amounts of tumor necrosis factor alpha. Overall, the extent of the endocytic and exocytic response of CBHMC correlated with the number of adherent bacteria. Thus, human mast cells are intrinsically capable of mediating microbial recognition and of actively contributing to the host defense against bacteria.
Immunogenicity of a 48-Kilodalton Recombinant T-Cell-Reactive Protein of
Coccidioides immitis
Authors: Kirkland Theo N. , Thomas Pei Wang , Finley Fred , Cole Garry T.
Published: December 2019

The outcome of coccidioidomycosis depends to a large extent on the effectiveness of the T-cell-mediated immune (CMI) response to the fungal pathogen. For this reason, identification of
Coccidioides immitis
antigens which stimulate T cells is important for understanding the nature of host defense against the organism and essential for the development of an effective vaccine. Here we describe the immunogenicity of a 48-kDa T-cell-reactive protein (TCRP). The antigen is expressed by parasitic cells and localized in the cytoplasm. It stimulates the proliferative response and production of gamma interferon by T cells of mice immunized with
C. immitis
spherules. Specific antibody reactive with the recombinant TCRP (rTCRP) was detected in sera of patients with confirmed coccidioidal infection, and the highest titers of antibody to the recombinant protein correlated with elevated titers to the serodiagnostic complement fixation antigen of
C. immitis
. These results suggest that the TCRP is presented to the host during the course of infection. Immunization of BALB/c and C3H/HeN mice with the rTCRP affords a modest but significant level of protection against an intraperitoneal challenge with
C. immitis
. It is suggested that the rTCRP may be able to contribute to a multicomponent vaccine designed to stimulate CMI response against the parasitic cycle of
C. immitis.
Role of Monocytes and Bacteria in
Staphylococcus epidermidis
Endocarditis
Authors: Bancsi Maurice J. L. M. F. , Veltrop Marcel H. A. M. , Bertina Rogier M. , Thompson Jan
Published: December 2019

The endocardial vegetation which is formed in the course of bacterial endocarditis (BE) contains tissue factor (TF)-dependent procoagulant activity. Earlier studies showed that monocytes are the main source of TF in the vegetations. The TF activity (TFA) of vegetations isolated from
Streptococcus sanguis
-infected rabbits depended on the numbers of bacteria as well as monocytes in the vegetation. In this study, we investigated whether for
Staphylococcus epidermidis
, a frequent pathogen in BE, an effect similar to that found for
S. sanguis
could be shown. In vitro,
S. epidermidis
was found to stimulate TFA of fibrin adherent monocytes significantly. This stimulation was maximal at a bacterium-to-monocyte ratio of 7. In vivo, TFA was found to be significantly higher in
S. epidermidis
-infected than in sterile catheter-induced vegetations. Reduction of vegetational bacterial numbers by teicoplanin treatment lead to a small but significant decrease of TFA. Reduction of monocyte numbers by etoposide did not affect vegetational TFA. Comparison of data for
S. epidermidis
and
S. sanguis
revealed that at equivalent bacterial numbers, vegetational TFAs were approximately the same for both microorganisms. Combining the results of the present study with those of a previous study using
S. sanguis
, we conclude that the main factor determining monocyte-dependent vegetational TFA is the number of vegetation-associated bacteria. The lower TFA found for
S. epidermidis
-infected than for
S. sanguis
-infected vegetations can be explained by the significantly lower bacterial numbers in the infected vegetations and consequently a lower stimulation of vegetation-associated monocytes.