bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interaction ofMycobacterium tuberculosis-Induced Transforming Growth Factor β1 and Interleukin-10
Authors: Othieno Catherine , Hirsch Christina S. , Hamilton Beverly D. , Wilkinson Katalin , Ellner Jerrold J. , Toossi Zahra 
Published: December 2019

ABSTRACTMycobacterium tuberculosisis associated with the activation of cytokine circuits both at sites of active tuberculosis in vivo and in cultures of mononuclear cells stimulated byM. tuberculosisor its components in vitro. Interactive stimulatory and/or inhibitory pathways are established between cytokines, which may result in potentiation or attenuation of the effects of each molecule on T-cell responses. Here we examined the interaction of transforming growth factor β1 (TGF-β1) and interleukin-10 (IL-10) in purified protein derivative (PPD)-stimulated human mononuclear cell cultures in vitro. TGF-β1 induced monocyte IL-10 (but not tumor necrosis factor alpha) production (by 70-fold,P< 0.02) and mRNA expression in the absence but not in the presence of PPD. Both exogenous recombinant (r) IL-10 and rTGF-β1 independently suppressed the production of PPD-induced gamma interferon (IFN-γ) in mononuclear cells from PPD skin test-positive individuals. Synergistic suppression of IFN-γ in cultures containing both rTGF-β1 and rIL-10 was only seen when the responder cell population were peripheral blood mononuclear cells (PBMC) and not monocyte-depleted mononuclear cells and when PBMC were pretreated with rTGF-β1 but not with rIL-10. Suppression of PPD-induced IFN-γ in PBMC containing both rTGF-β1 (1 ng/ml) and rIL-10 (100 pg/ml) was 1.5-fold higher (P< 0.05) than cultures containing TGF-β1 alone and 5.7-fold higher (P< 0.004) than cultures containing IL-10 alone. Also, neutralization of endogenous TGF-β1 and IL-10 together enhanced PPD-induced IFN-γ in PBMC in a synergistic manner. Thus, TGF-β1 and IL-10 together potentiate the downmodulatory effect onM. tuberculosis-induced T-cell production of IFN-γ, and TGF-β1 alone enhances IL-10 production. At sites of activeM. tuberculosisinfection, these interactions may be conducive to the suppression of mononuclear cell functions.
Upregulation of p75 Tumor Necrosis Factor Alpha Receptor inMycobacterium avium-Infected Mice: Evidence for a Functional Role
Authors: Corti Angelo , Fattorini Lanfranco , Thoresen Ove Fredrik , Ricci Maria Luisa , Gallizia Anna , Pelagi Micaela , Li Yongjun , Orefici Graziella 
Published: December 2019

ABSTRACTThe bacterial growth and the production of tumor necrosis factor alpha (TNF-α) and TNF receptors (TNF-Rs) in the spleen and blood of BALB/c mice challenged withMycobacterium aviumcomplex (MAC) were monitored. Infection developed in two phases: the first, up to day 21, was associated with rapid MAC multiplication in the spleen and a drop in the mycobacteremia, and the second was associated with control of the infection in both compartments. In the spleen, TNF-α and TNF-RII mRNA levels peaked on day 21 and then slowly decreased; however, no increase in the level of TNF-RI mRNA was observed throughout these experiments. The level of circulating soluble TNF-RII (sTNF-RII) was transiently increased after day 21. In a model in which overproduction of bioactive TNF-α was triggered in response to a second infection with MAC, an increased production of sTNF-RII by cultured splenocytes was also observed. Administration of an antagonist anti-TNF-RII monoclonal antibody (MAb 6G1) to infected mice inhibited the bacterial growth in the spleen, suggesting that the TNF-RII and/or sTNF-RII was functionally involved in the mechanisms that control the infection. Overall, these observations suggest that upregulation of TNF-RII or sTNF-RII contributes to modulation of the TNF-α antibacterial activity in MAC infections.
Genomic Analysis Reveals Variation between
Mycobacterium tuberculosis
H37Rv and the Attenuated
M. tuberculosis
H37Ra Strain
Authors: Brosch Roland , Philipp Wolfgang J. , Stavropoulos Evangelos , Colston M. Joseph , Cole Stewart T. , Gordon Stephen V. 
Published: December 2019

ABSTRACT

Mycobacterium tuberculosis
H37Ra is an attenuated tubercle bacillus closely related to the virulent type strain
M. tuberculosis
H37Rv. Despite extensive study, the reason for the decreased virulence of
M. tuberculosis
H37Ra has not been determined. A genomic approach was therefore initiated to identify genetic differences between
M. tuberculosis
H37Rv and
M. tuberculosis
H37Ra as a means of pinpointing the attenuating mutation(s). Digestion with the rare-cutting restriction endonuclease
Dra
I revealed two polymorphisms between the strains: a 480-kb fragment in
M. tuberculosis
H37Rv was replaced by two fragments of 220 and 260 kb in
M. tuberculosis
H37Ra, while there was a ∼7.9-kb
Dra
I fragment in
M. tuberculosis
H37Ra that had no counterpart in
M. tuberculosis
H37Rv. As the
M. tuberculosis
insertion sequence IS
6110
contains a single
Dra
I restriction site, it was considered possible that these polymorphisms were the result of IS
6110
transposition events in
M. tuberculosis
H37Ra, events that may have inactivated virulence genes. The 7.9-kb polymorphism was found to be due to the presence of the previously described H37Rv RvD2 deletion in
M. tuberculosis
H37Ra, with sequence analysis suggesting an IS
6110
-mediated deletion mechanism for loss of RvD2. Three other IS
6110
-catalyzed deletions from the
M. tuberculosis
H37Rv chromosome (RvD3 to RvD5) were also identified, suggesting that this mechanism plays an important role in genome plasticity in the tubercle bacilli. Comparative mapping and sequencing revealed that the 480-kb polymorphism was due to an IS
6110
insertion in
M. tuberculosis
H37Ra near
oriC
. Complementation of
M. tuberculosis
H37Ra with a 2.9-kb restriction fragment from
M. tuberculosis
H37Rv that encompassed the IS
6110
insertion did not increase the survival of recombinant
M. tuberculosis
H37Ra in mice. In conclusion, this study describes the presence and mechanisms of genomic variation between
M. tuberculosis
H37Ra and
M. tuberculosis
H37Rv, although the role that they play in the attenuation of
M. tuberculosis
H37Ra is unclear.
Native and Mutant Forms of Cholera Toxin and Heat-Labile Enterotoxin Effectively Enhance Protective Efficacy of Live Attenuated and Heat-KilledShigellaVaccines
Authors: Hartman Antoinette B. , Van De Verg Lillian L. , Venkatesan Malabi M. 
Published: December 2019

ABSTRACTBoth native and mutant forms of cholera toxin (CT) and heat-labile enterotoxin (LT) are effective adjuvants for antigens and killed whole-cell preparations. To determine whether these toxin molecules could also boost the immunogenicity and efficacy of live attenuated vaccines directed against shigellosis, the guinea pig keratoconjunctivitis model was used to evaluate the adjuvant effect of these toxin molecules on EcSf2a-3, a ΔvirG ΔaroD Escherichia coli-Shigella flexneri2a hybrid vaccine strain that was previously found to be less protective than its parent strain in the guinea pig model. Experiments using native and mutant toxin molecules showed that both CT and LT and mutant derivatives were effective as an adjuvant for EcSf2a-3 and that the mutant toxin molecules, which were developed to retain adjuvanticity without the toxicity associated with the native molecules, were as effective as the native toxin molecules as adjuvants. Protective efficacy was enhanced for both the oral and intranasal routes of immunization. Serum antibody response to theS. flexneri2a O antigen, the primary antigen for protective immunity, was not dependent on the addition of an adjuvant. However, enumeration of the O-antigen-specific immunoglobulin G (IgG) and IgA antibody-secreting cells in the spleen and draining lymph nodes following intranasal immunization suggested that enhancement of the local immune response by the toxin molecules may contribute to the observed increase in protective efficacy. The efficacy of heat-killedS. flexneri2a was enhanced only by mutant LT molecules. These results suggest that the best candidates for enhancing the efficacy of both live attenuated and heat-killedShigellavaccines with minimal reactogenicity are the mutant toxin molecules.
Coadministration of Interleukin 12 Expression Vector with Antigen 2 cDNA Enhances Induction of Protective Immunity againstCoccidioides immitis
Authors: Jiang Chengyong , Magee D. Mitchell , Cox Rebecca A. 
Published: December 2019

ABSTRACTInterleukin 12 (IL-12) plays an important role in the induction of protective immunity against cancer and infectious diseases. In this study we asked whether IL-12 cDNA could increase the protective capacity of the antigen 2 (Ag2) gene vaccine in experimental coccidioidomycosis. Coimmunization of BALB/c mice with a single-chain IL-12 cDNA (p40-L-p35) and Ag2 cDNA, both subcloned into the pVR1012 plasmid, significantly enhanced protection against systemic challenge with 2,500 arthroconidia, as evidenced by a greater-than-1.3-log-unit reduction in the fungal load in the lungs and spleens compared to mice receiving the pVR1012 vector alone, Ag2 cDNA alone, or IL-12 cDNA alone. The enhanced protection was associated with increased gamma interferon secretion; production of immunoglobulin G2a (IgG2a), IgG2b, and IgG3 antibodies toCoccidioides immitisantigen; and the influx of CD4+and CD8+T cells in lungs and spleens. When challenged by the pulmonary route, mice covaccinated with Ag2 cDNA and IL-12 cDNA were not protected at the lung level but did show a significant reduction in the fungal load in their livers and spleens compared to mice vaccinated with Ag2 cDNA or IL-12 cDNA alone. These results suggest that IL-12 acts as a therapeutic adjuvant to enhance Ag2 cDNA-induced protective immunity against experimental coccidioidomycosis through the induction of Th1-associated immune responses.
Immune CD8+T Cells Prevent Reactivation ofToxoplasma gondiiInfection in the Immunocompromised Host
Authors: Khan Imtiaz A. , Green William R. , Kasper Lloyd H. , Green Kathy A. , Schwartzman Joseph D. 
Published: December 2019

ABSTRACTToxoplasma gondiiremains a serious cause of morbidity and mortality in individuals that are immunosuppressed, patients with AIDS in particular. The cellular immune response, especially by gamma interferon (IFN-γ)-producing CD8+T cells, is an essential component of protective immunity against the parasite. In the present study the role of CD8+T cells during the reactivation ofToxoplasmainfection in an immunocompromised murine model was evaluated. Chronically infected mice were challenged with LP-BM5 virus, and the kinetics of CD8+T-cell function was studied. At 10 weeks after viral infection, mice showed obvious signs of systemic illness and began to die. At this stage, CD8+T cells were unresponsive to antigenic stimulation and unable to killToxoplasma-infected targets. IFN-γ production by the CD8+T cells from dual-infected animals reached background levels, and a dramatic fall in the frequency of precursor cytotoxic T lymphocytes was observed. Histopathological analysis of the tissues demonstrated signs of disseminated toxoplasmosis as a result of reactivation of infection. However, treatment of the dual-infected animals with immune CD8+T cells at 5 weeks post-LP-BM5 challenge prevented the reactivation of toxoplasmosis, and mice continued to live. Our study for the first time demonstrates a therapeutic role for CD8+T cells against an opportunistic infection in an immunocompromised state.
Klebsiella pneumoniae
Capsule Expression Is Necessary for Colonization of Large Intestines of Streptomycin-Treated Mice
Authors: Favre-Bonté Sabine , Licht Tine Rask , Forestier Christiane , Krogfelt Karen Angeliki 
Published: December 2019

ABSTRACT

The role of the
Klebsiella pneumoniae
capsular polysaccharide (K antigen) during colonization of the mouse large intestine was assessed with wild-type
K. pneumoniae
LM21 and its isogenic capsule-defective mutant. When bacterial strains were fed alone to mice, the capsulated bacteria persisted in the intestinal tract at levels of 10
8
CFU/g of feces while the capsule-defective strain colonized at low levels, 10
4
CFU/g of feces. In mixed-infection experiments, the mutant was rapidly outcompeted by the wild type. In situ hybridization on colonic sections revealed that bacterial cells of both strains were evenly distributed in the mucus layer at day 1 after infection, while at day 20 the wild type remained dispersed and the capsule-defective strain was seen in clusters in the mucus layer. These results suggest that capsular polysaccharide plays an important role in the gut colonization ability of
K. pneumoniae
.
Characterization of a Novel Methyl-Accepting Chemotaxis Gene,
dmcB
, from the Oral Spirochete
Treponema denticola
Authors: Li Hong , Arakawa Shinichi , Deng Qing-Dong , Kuramitsu Howard 
Published: December 2019

ABSTRACT

Immediately downstream from the previously isolated
Treponema denticola
ATCC 35405
prtB
gene coding for a chymotrypsinlike protease activity, an open reading frame, ORF3, was identified which shared significant homology with the highly conserved domains (HCDs) of bacterial methyl-accepting chemotaxis proteins (MCPs). Nucleotide sequencing of this ORF revealed that the gene would code for a protein with a size of approximately 41 kDa. In addition, this sequence contained a domain which was virtually identical to the HCD of a recently characterized MCP, DmcA, of strain 35405. Therefore, this ORF was named
dmcB
. Northern blot analysis suggested that
dmcB
was part of an operon structure containing
prtB
. Insertional inactivation of
dmcB
utilizing an
ermF-ermAM
cassette resulted in a mutant with decreased chemoattraction toward nutrient supplements. In addition, the mutant displayed an altered pattern of methylated proteins under conditions of chemotaxis. Inactivation of the
dmcB
gene also attenuated the methylation of the DmcA protein. These results suggest that the
dmcB
gene codes for an MCP in
T. denticola
which may interact with other MCPs in these organisms.
Effectiveness of a Vaccine Composed of Heat-KilledCandida albicansand a Novel Mucosal Adjuvant, LT(R192G), against Systemic Candidiasis
Authors: Cárdenas-Freytag Lucía , Cheng Elly , Mayeux Patricia , Domer Judith E. , Clements John D. 
Published: December 2019

ABSTRACTThe incidence of fungal infections caused by the opportunistic yeastCandida albicanshas increased significantly in recent years. The ability to vaccinate selected patients against the organism would be advantageous. In this paper we describe a potential anti-C. albicansvaccine consisting of heat-killedC. albicans(HK-CA) in combination with the novel mucosal adjuvant LT(R192G), a genetically detoxified form of the heat-labile toxin of enterotoxigenicEscherichia coli. Groups of male CBA/J mice were immunized intranasally on three occasions at weekly intervals with 2 × 107HK-CA per dose, alone or in conjunction with 10 μg of LT(R192G) per dose. Two weeks following the last application of antigen, some animals were challenged intravenously (i.v.) with 104, 105, or 106viableC. albicansto assess protection as measured by survival and/or culture. Some groups of animals were footpad tested withC. albicansmannan to assess delayed-type hypersensitivity (DTH), and all the animals were bled for antibody assays. In two independent studies, all the animals immunized with HK-CA plus LT(R192G) were able to eradicate 104C. albicanscompletely, as determined by kidney culture 4 weeks after challenge. Animals immunized with HK-CA only had reduced levels ofC. albicanscompared to the adjuvant or saline-only control. Greatly enhanced survival was observed when mice immunized with HK-CA plus LT(R192G) were challenged with 105liveC. albicansas well. Animals immunized with HK-CA plus LT(R192G) developed a significant DH response, while those given HK-CA alone developed only marginal DH responses. High immunoglobulin G (IgG) levels to cytoplasmic antigens developed in mice immunized with HK-CA plus LT(R192G), but they were found only after i.v. challenge. Addition of adjuvant shifted the antibody isotype production in i.v.-challenged animals to a response dominated by IgG2a. Clearly, intranasal immunization with killedC. albicansin conjunction with LT(R192G) afforded significant levels of protection. This novel approach offers new possibilities for the development of an effective vaccine against candidiasis for use in humans.
Comparative Virulence of
Streptococcus pneumoniae
Strains with Insertion-Duplication, Point, and Deletion Mutations in the Pneumolysin Gene
Authors: Berry Anne M. , Ogunniyi A. David , Miller David C. , Paton James C. 
Published: December 2019

ABSTRACT

Pneumolysin is a 471-amino-acid toxin produced by
Streptococcus pneumoniae
which has both cytolytic and complement activation properties. We have constructed a derivative of the type 2
S. pneumoniae
strain D39 in which the portion of the pneumolysin gene encoding amino acids 55 to 437 has been deleted in-frame. The virulence of this strain (ΔPly) was compared with those of wild-type D39, a pneumolysin insertion-duplication mutant (PLN-A), and a derivative (PdT) carrying a toxin gene with three point mutations known to abolish both cytolytic activity and complement activation. PdT was intermediate in virulence between D39 and either PLN-A or ΔPly in a mouse intraperitoneal challenge model. This provides unequivocal evidence that pneumolysin has an additional property that is not abolished by point mutations which reduce cytotoxicity and complement activation to virtually undetectable levels.
Enhanced Th1 and Dampened Th2 Responses Synergize To Inhibit Acute Granulomatous and Fibrotic Responses in Murine Schistosomiasis Mansoni
Authors: Boros Dov L. , Whitfield Joel R. 
Published: December 2019

ABSTRACTIn murine schistosomiasis mansoni, CD4+Th1 and Th2 cells participate in the ovum-induced granulomatous inflammation. Previous studies showed that the interleukin-12 (IL-12)-induced Th1 response strongly suppressed the Th2-cell-mediated pulmonary granuloma development in naive or primed mice. However, liver granulomas were only moderately suppressed in egg-vaccinated, recombinant IL-12 (rIL-12)-treated infected mice. The present study shows that repeated rIL-12 injections given during early granuloma development at 5 to 7 weeks after infection prolonged the Th1 phase and resulted in gamma interferon-mediated suppression of liver granulomas. The timing is crucial: if given at 6 to 8 weeks, during the Th2-dominated phase of florid granuloma growth, the treatment is ineffective. Daily injections of rIL-12 given between 5 and 7.5 weeks during the period of granuloma growth achieved a somewhat-stronger diminution in granuloma growth with less deposition of collagen but caused 60% mortality and liver pathology. In contrast, combined treatment with rIL-12 and anti-IL-4–anti-IL-10 monoclonal antibody (MAb) injections given during the Th2 phase strongly inhibited liver granuloma growth without mortality. The diminished inflammatory response was accompanied by less deposition of collagen in the liver. Moreover, neutralization of endogenous IL-12 by anti-IL-12 MAbs effectively decreased the early Th1 phase (between 5 and 6 weeks after infection) but not the developing Th2 phase (5 to 7 weeks) of granuloma development. These studies indicate that the granulomatous response in infected mice can be manipulated by utilizing the Th1-Th2-subset antagonism with potential salutary results in the amelioration of fibrous pathology.
Zonula Occludens Toxin Is a Powerful Mucosal Adjuvant for Intranasally Delivered Antigens
Authors: Marinaro Mariarosaria , di Tommaso Annalisa , Uzzau Sergio , Fasano Alessio , de Magistris Maria Teresa 
Published: December 2019

ABSTRACTZonula occludens toxin (Zot) is produced by toxigenic strains ofVibrio choleraeand has the ability to reversibly alter intestinal epithelial tight junctions, allowing the passage of macromolecules through the mucosal barrier. In the present study, we investigated whether Zot could be exploited to deliver soluble antigens through the nasal mucosa for the induction of antigen-specific systemic and mucosal immune responses. Intranasal immunization of mice with ovalbumin (Ova) and recombinant Zot, either fused to the maltose-binding protein (MBP-Zot) or with a hexahistidine tag (His-Zot), induced anti-Ova serum immunoglobulin G (IgG) titers that were approximately 40-fold higher than those induced by immunization with antigen alone. Interestingly, Zot also stimulated high anti-Ova IgA titers in serum, as well as in vaginal and intestinal secretions. A comparison withEscherichia coliheat-labile enterotoxin (LT) revealed that the adjuvant activity of Zot was only sevenfold lower than that of LT. Moreover, Zot and LT induced similar patterns of Ova-specific IgG subclasses. The subtypes IgG1, IgG2a, and IgG2b were all stimulated, with a predominance of IgG1 and IgG2b. In conclusion, our results highlight Zot as a novel potent mucosal adjuvant of microbial origin.
Cryptosporidium parvumSporozoite Pellicle Antigen Recognized by a Neutralizing Monoclonal Antibody Is a β-Mannosylated Glycolipid
Authors: Riggs Michael W. , McNeil Michael R. , Perryman Lance E. , Stone Alice L. , Scherman Michael S. , O’Connor Roberta M. 
Published: December 2019

ABSTRACTThe protozoan parasiteCryptosporidium parvumis an important cause of diarrhea in humans, calves, and other mammals worldwide. No approved vaccines or parasite-specific drugs are currently available for the control of cryptosporidiosis. To effectively immunize againstC. parvum, identification and characterization of protective antigens are required. We previously identified CPS-500, a conserved, neutralization-sensitive antigen ofC. parvumsporozoites and merozoites defined by monoclonal antibody 18.44. In the present study, the biochemical characteristics and subcellular location of CPS-500 were determined. CPS-500 was chloroform extractable and eluted with acetone and methanol in silicic acid chromatography, consistent with being a polar glycolipid. Following chloroform extraction and silicic acid chromatography, CPS-500 was isolated by high-pressure liquid chromatography for glycosyl analysis, which indicated the presence of mannose and inositol. To identify which component of CPS-500 comprised the neutralization-sensitive epitope recognized by 18.44, the ability of the monoclonal antibody to bind CPS-500 treated with proteases, or with α- or β-glycosidases, was determined. Monoclonal antibody 18.44 did not bind antigen treated with β-d-mannosidase but did bind antigen treated with α-d-mannosidase, other α- or β-glycosidases, or a panel of proteases. These data indicated that the target epitope was dependent on terminal β-d-mannopyranosyl residues. By immunoelectron microscopy, 18.44 binding was localized to the pellicle and an intracytoplasmic tubulovesicular network in sporozoites. Monoclonal antibody 18.44 also bound to antigen deposited and released onto substrate over the course travelled by gliding sporozoites and merozoites. Surface localization, adhesion and release during locomotion, and neutralization sensitivity suggest that CPS-500 may be involved in motility and invasion processes of the infective zoite stages.