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Biomedical subjects

H Moll

Publications and source records attributed to H Moll.

At least 37 records · Page 2Linked to original sources
PubMed1999

Constitutive expression of interleukin 4 in vivo does not lead to the development of T helper 2 type CD8+ T cells secreting interleukin 4 or interleukin 5.

Interleukin 4 (IL-4) has been shown to commit CD8+ T cells to a T helper (Th) 2 functional phenotype in vitro. To study the effects of IL-4 on CD8+ T cell development in vivo we analysed the CD8+ T cell phenotype in mice constitutively expressing IL-4. Purified CD8+ T cells from uninfected or flu infected IL-4 transgenic (tg) animals produced no detectable IL-4 or IL-5 after in vitro stimulation on anti-CD3 coated plates. However, CD8+ T cells from IL-4 tg mice could be converted into IL-4 and IL-5 producers in vitro in the presence of exogenous added IL-4, showing that these cells were still responsive to IL-4. IL-4 tg mice also showed a delay in influenza virus clearance from the lung, which was probably due to the observed reduction of total CD8+ T cell numbers in the IL-4 tg animals since IL-4 tg CD8+ T cells showed normal levels of influenza-specific cytotoxicity in comparison to controls. Taken together these results suggest that CD8+ T cells are not necessarily switched to a Th2 phenotype by the presence of IL-4 and that some other factor(s) may be important in the switch process of CD8+ T cells in vivo, since the addition of IL-4 during CD8+ T cell activation in vitro leads to Th2 type CD8+ T cells secreting IL-4 and IL-5.

Animals↗
PubMed1999

Treatment of two patients with diffuse cutaneous leishmaniasis caused by Leishmania mexicana modifies the immunohistological profile but not the disease outcome.

Two patients with diffuse cutaneous leishmaniasis caused by Leishmania mexicana were treated with two leishmanicidal drugs (pentamidine and allopurinol) combined with recombinant interferon-gamma restoring Th-1 favouring conditions in the patients. Parasites decreased dramatically in the lesions and macrophages diminished concomitantly, while IL-12-producing Langerhans cells and interferon-gamma- producing NK and CD8 + lymphocytes increased in a reciprocal manner. The CD4+/CD8 + ratio in the peripheral blood normalized. During exogenous administration of interferon-gamma the parasites' capacity to inhibit the oxidative burst of the patients' monocytes was abolished. Even though Th-1-favouring conditions were restored, both patients relapsed two months after therapy was discontinued. We conclude that the tendency to develop a disease-promoting Th-2 response in DCL patients is unaffected by, and independent of, parasite numbers. Even though intensive treatment in DCL patients induced Th-1 disease restricting conditions, the disease-promoting immunomodulation of few persistent Leishmania sufficed to revert the immune response.

Allopurinol↗
PubMed1999

Structure of the O-specific polysaccharide of a serologically separate strain Proteus penneri 2 from a new proposed serogroup O66.

O-specific polysaccharide chain of Proteus penneri strain 2 lipopolysaccharide was studied by full and partial acid hydrolysis, Smith degradation, methylation analysis, and NMR spectroscopy, including two-dimensional rotating-frame NOE spectroscopy (ROESY) and 1H,13C heteronuclear multiple-quantum coherence (HMQC) experiments. Together with D-glucose and 2-acetamido-2-deoxy-D-glucose, the polysaccharide was found to contain two rarely occurring sugars, 6-deoxy-L-talose (L-6dTal) and 2,3-diacetamido-2,3,6-trideoxy-L-mannose (L-RhaNAc3NAc), and the following structure of a non-stoichiometrically O-acetylated tetrasaccharide repeating unit was established: [equation: see text] The O-specific polysaccharide studied has a unique composition and structure and, accordingly, P. penneri 2 is serologically separate among Proteus strains. Therefore, we propose for P. penneri 2 a new Proteus O-serogroup O66 where this strain is at present the single representative.

Carbohydrate Conformation↗
PubMed1999

Infection of mice with Mycobacterium bovis-BCG induces both Th1 and Th2 immune responses in the absence of interferon-gamma signalling.

A murine pulmonary infection model using Mycobacterium bovis-BCG was used to study the development of Th1 and Th2 type responses in mice lacking a functional IFN-gamma receptor (IFN-gamma R-/-). Strikingly, the IFN-gamma R-/- mice maintained the Th1 response and developed a profound M. bovis-BCG, specific Th2 type immune response characterized by IL-5-producing CD4+ T cells, eosinophil infiltration of granulomas, and significantly elevated serum IgE levels. The increase in IL-5 production and eosinophil recruitment into the lung could be detected within the first 1-2 weeks of infection, indicating that the Th2 response was not due to greatly enhanced bacterial numbers observed later in infection. These results clearly indicate that IFN-gamma acts during M. bovis-BCG infection to suppress the development of Th2 immune responses. Furthermore, they demonstrate that IFN-gamma is not a necessary cofactor in the development of Th1 type cells secreting IFN-gamma. In conclusion, these data demonstrate that IFN-gamma plays a major role in suppressing a potentially disease-promoting Th2 immune response during mycobacterial infections.

Animals↗
PubMed1998

Cytochrome b558/566 from the archaeon Sulfolobus acidocaldarius. A novel highly glycosylated, membrane-bound b-type hemoprotein.

In this study we re-examined the inducible cytochrome b558/566 from the archaeon Sulfolobus acidocaldarius (DSM 639), formerly thought to be a component of a terminal oxidase (Becker, M., and Schäfer, G. (1991) FEBS Lett. 291, 331-335). An improved purification method increased the yield of the protein and allowed more detailed investigations. Its molecular mass and heme content have been found to be 64,210 Da and 1 mol of heme/mol of protein, respectively. It is only detectable in cells grown at low oxygen tensions. The composition of the growth medium also exerts significant influence on the cytochrome b558/566 content of S. acidocaldarius membranes. The cytochrome exhibits an extremely high redox potential of +400 mV and shows no CO reactivity; a ligation other than a His/His-coordination of axial ligands appears likely. It turned out to be highly glycosylated (more than 20% of its molecular mass are sugar residues) and is probably exposed to the outer surface of the plasma membrane. The sugar moiety consists of several O-glycosidically linked mannoses and at least one N-glycosidically linked hexasaccharide comprising two glucoses, two mannoses, and two N-acetyl-glucosamines. The gene of the cytochrome (cbsA) has been sequenced, revealing an interesting predicted secondary structure with two putative alpha-helical membrane anchors flanking the majority of a mainly beta-pleated sheet structure containing unusually high amounts of serine and threonine. A second gene (cbsB) was found to be cotranscribed. The latter displays extreme hydrophobicity and is thought to form a functional unit with cytochrome b558/566 in vivo, although it did not copurify with the latter. Sequence comparisons show no similarity to any entry in data banks indicating that this cytochrome is indeed a novel kind of b-type hemoprotein. A cytochrome c analogous function in the pseudoperiplasmic space of S. acidocaldarius is discussed.

Amino Acid Sequence↗
PubMed1998

Infection of mice with Mycobacterium bovis-Bacillus Calmette-Guérin (BCG) suppresses allergen-induced airway eosinophilia.

It has been proposed that the increase in prevalence and severity of atopic disorders inversely correlates with exposure to infectious diseases such as tuberculosis. We have investigated this issue by combining an intranasal Mycobacterium bovis-Bacillus Calmette-Guérin (BCG) infection with a murine model of allergen, (ovalbumin [OVA]) induced airway eosinophilia. BCG infection either 4 or 12 wk before allergen airway challenge resulted in a 90-95 and 60-70% reduction in eosinophilia within the lungs, respectively, compared to uninfected controls. The inhibition of airway eosinophilia correlated with a reduced level of IL-5 production by T cells from the lymph node draining the site of OVA challenge. Interestingly, BCG infection of the lung had no effect on IgG1 and IgE OVA-specific serum immunoglobulin or blood eosinophil levels. Furthermore, BCG-induced inhibition of airway eosinophilia was strongly reduced in interferon (IFN)-gamma receptor-deficient mice and could be partially reversed by intranasal IL-5 application. Intranasal BCG infections could also reduce the degree of lung eosinophilia and IL-5 produced by T cells after Nippostrongylus brasiliensis infection. Taken together, our data suggest that IFN-gamma produced during the T helper cell (Th)1 immune response against BCG suppresses the development of local inflammatory Th2 responses in the lung. Most importantly, this inhibition did not extend to the systemic immunoglobulin response against OVA. Our data support the view that mycobacterial infections have the potential to suppress the development of atopic disorders in humans.

Adjuvants, Immunologic↗
PubMed1998

Antigen-pulsed epidermal Langerhans cells protect susceptible mice from infection with the intracellular parasite Leishmania major.

Efficient vaccination against the parasite Leishmania major, the causative agent of human cutaneous leishmaniasis, requires the development of a resistance-promoting CD4+-mediated Th1 response. Epidermal Langerhans cells (LC) are critically involved in the induction of the primary immune response to Leishmania infection. They are able to ingest the parasites, to express MHC class II molecules with extraordinarily long half-life and to activate naive L. major-specific Th cells. Considering these unique properties, we studied the capacity of LC to mediate resistance to L. major in vivo. A single i.v. application of LC that had been pulsed with L. major antigen in vitro induced the protection in susceptible BALB/c mice against subsequent challenges with L. major parasites. Resistance could neither be induced by unpulsed LC, nor by L. major antigen alone or by L. major-pulsed macrophages. Development of resistance was paralleled by a reduced parasite burden and by a shift of the cytokine expression towards a Th1-like pattern. In contrast, control mice developed a Th2 response. In vitro exposure of LC to L. major antigen induced the expression of IL-12 (p40) mRNA. In conclusion, our data demonstrate that LC are able to serve as a natural adjuvant and to induce a protective immune response to L. major infection. This effect is based on the initiation of a Th1-like response that is likely to be mediated by IL-12.

Animals↗
PubMed1998

Leishmania sp.: growth and survival are impaired by ion channel blockers.

In the present work we examined the effect of ion transport blockers on the growth and viability of Leishmania sp. and on the infection of macrophages by the parasite. 4-aminopyridine and glibenclamide block voltage-dependent and K+ ATP channels, respectively; amiloride is used to detect Na+ channels and Na+/H+ antiporters; and anthracene-9-carboxylic acid affects chloride channels. The EC50 for promastigote cultures of three strains of the Leishmania subgenus, namely, Leishmania (Leishmania) NR, Leishmania (Leishmania) amazonensis LTB0016, and Leishmania (Leishmania) major, at their stationary phase of growth, were, respectively, 39, 46, and 464 microM for 4-aminopyridine; 7, 0.8, and 10 microM for glibenclamide and 66, 170, and 10 microM for anthracene-9-carboxylic acid. The amiloride EC50 for NR was 264 microM and 10 microM for L. (L.) major, but was never reached for LTB0016. Higher concentrations of the drugs impaired the exponential growth of Leishmania promastigotes. These results suggest the susceptibility of Leishmania sp. to blockers associated with K+ and Cl- and to Na+ or Na+/H+ transport systems. Blockade of such systems might have impaired the survival of the parasites as promastigotes. In addition, it affected the persistence of parasites in host cells. Although the infection of the macrophage cell line J774 and peritoneal-exudate macrophages was not significantly decreased by concentrations of the drugs around the promastigotes' EC50, the survival of intracellular parasites decreased significantly in the presence of these drugs without affecting the viability of the macrophages. Some blockers consistently gave small EC50 and significantly decreased the infection process as well as the survival of intracellular parasites. Thus, elucidation of their mechanism of action in Leishmania is relevant, since they could represent a potential subject for the development of leishmanicidal drugs.

4-Aminopyridine↗
PubMed1998

Structural studies on the lipopolysaccharide from a rough strain of Ochrobactrum anthropi containing a 2,3-diamino-2,3-dideoxy-D-glucose disaccharide lipid A backbone.

A degradation protocol using de-O-acylation and subsequent alkaline de-N-acylation was applied to the lipopolysaccharide of Ochrobactrum anthropi rough strain LMG 3301. Three main oligosaccharide bisphosphates containing core-lipid A backbone structures were obtained after fractionation by anion-exchange HPLC. Using 1H and 13C NMR spectroscopy, including two-dimensional COSY, TOCSY, and NOE spectroscopy (ROESY and NOESY), the following structures were established: [formula: see text] where Kdo is 3-deoxy-D-manno-octulosonic acid, D-GlcN3N is 2,3-diamino-2,3-dideoxy-D- glucose and R is H or alpha-D-GalpA or 4-deoxy-beta-L-threo-hex-4-enopyranuronic acid, the latter sugar being derived from alpha-D-GalpA by beta-elimination of a substituent attached to 0-4. This is the first report on the isolation from a lipopolysaccharide of an oligosaccharide containing GlcN3N in the lipid A backbone [beta-D-GlcpN3N4P-(1-->6)-alpha-D-GlcpN3N1 P]. Sugar and methylation analysis confirmed the presence of the GalA-->Kdo disaccharide and non-stoichiometric substitution of GalA. It is suggested that Glc is the substituent at 0-4 in GalA and that in the non-degraded lipopolysaccharide the amino group of GlcN is not acylated.

Carbohydrate Sequence↗
PubMed1998

Langerhans cell migration in murine cutaneous leishmaniasis: regulation by tumor necrosis factor alpha, interleukin-1 beta, and macrophage inflammatory protein-1 alpha.

After intradermal infection of mice with the obligatory intracellular parasite Leishmania major, Langerhans cells (LC) are intimately involved in the induction of the primary T-cell immune response. LC can phagocytose Leishmania and transport ingested parasites from the infected skin to the regional lymph nodes. Since TNF alpha and IL-1 beta have been shown to induce LC migration after epicutaneous exposure to skin-sensitizing chemicals, we investigated the involvement of both cytokines in the migration of Leishmania-infected LC. In addition, the relevance of two chemokines of the beta subfamily, macrophage inflammatory protein 1 alpha (MIP-1 alpha) and macrophage chemoattractant protein 1 (MCP-1), was analyzed. In vivo depletion of TNF alpha significantly reduced the amount of infected LC and the parasite load in the draining lymph nodes. Administration of recombinant TNF alpha caused the reverse effect. In contrast, the depletion of IL-1 beta enhanced the parasite-induced LC migration, whereas treatment with recombinant IL-1 beta, as well as recombinant MIP-1 alpha, reduced the rate of infected LC in the lymph nodes. MCP-1 did not influence LC migration. Our data demonstrate that TNF alpha and IL-1 beta are regulating the LC-mediated transport of Leishmania and also provide evidence for the involvement of macrophage attractant chemokines in this process.

Animals↗
PubMed1997

Elucidation of the structure of the core region and the complete structure of the R-type lipopolysaccharide of Erwinia carotovora FERM P-7576.

An R-type lipopolysaccharide (LPS) from Erwinia carotovora strain FERM P-7576 was studied after strong alkaline degradation and mild acid hydrolysis. The resulting products were analyzed by fast-atom bombardment mass spectrometry, one- and two-dimensional 1H and 13C NMR spectroscopy, dephosphorylation and methylation analysis. The following structure was proposed for the core region of the LPS: [formula in text] where Hep is L-glycero-D-manno-heptose and Kdo is 3-deoxy-D-manno-octulosonic acid. Some LPS species lack the beta-D-Galp residue or the beta-D-Galp-(1-->7)-alpha-Hepp disaccharide. With the known structures of lipid A [Fukuoka, S., Kamishima, H., Nagawa, Y., Nakanishi, H., Ishikawa, K., Niwa, Y., Tamiya, E. & Karube, I. (1992) Arch. Microbiol. 157, 311-318] and the core moiety, the complete LPS structure was established and confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry of the native and O-deacylated LPS.

Carbohydrate Conformation↗
PubMed1997

Identification of an alpha-D-Manp-(1-->8)-Kdo disaccharide in the inner core region and the structure of the complete core region of the Legionella pneumophila serogroup 1 lipopolysaccharide.

A disaccharide alpha-D-mannopyranosyl-(1-->8)-3-deoxy-D-manno-octulosonic acid [alpha-D-Manp-(1-->8)-Kdo] was released by mild acid degradation of Legionella pneumophila serogroup 1 (strain Philadelphia 1) lipopolysaccharide (LPS) and identified using NMR spectroscopy and GLC-MS of derived products. These data, together with methylation analysis of the native LPS and previously reported data [Y.A. Knirel, H. Moll, and U. Zähringer, Carbohydr. Res., 293 (1996) 223-234], allowed elucidation of the complete core region of the LPS as having the following nonasaccharide structure: [Sequence: see text]

Carbohydrate Conformation↗
PubMed1997

Chemical characterization of a new 5,7-diamino-3,5,7,9-tetradeoxynonulosonic acid released by mild acid hydrolysis of the Legionella pneumophila serogroup 1 lipopolysaccharide.

A derivative of a new 5,7-diamino-3,5,7,9-tetradeoxynonulosonic acid was released from the lipopolysaccharide of Legionella pneumophila serogroup 1 (strain Philadelphia 1) by mild acid hydrolysis, and identified, using NMR spectroscopy and GLC-MS, as 5,7-diacetamido-8-O-acetyl-3,5,7,9-tetradeoxy-L-glycero-D-talo- nonulosonic acid or its enantiomer.

Gas Chromatography-Mass Spectrometry↗
PubMed1997

Structure of a new 6-deoxy-alpha-D-talan from Burkholderia (Pseudomonas) plantarii strain DSM 6535, which is different from the O-chain of the lipopolysaccharide.

An O-acetylated homopolysaccharide of 6-deoxy-D-talose (6-deoxy-alpha-D-talan polymer) was isolated from Burkholderia (Pseudomonas) plantarii strain DSM 6535 by extraction with 2-propanol. The structure (1) of the trisaccharide repeating unit of the polysaccharide was established by studies of the intact and O-deacetylated polysaccharides using methanolysis, methylation analysis, 1H and 13C NMR spectroscopy, including 2D COSY, heteronuclear 13C, 1H COSY, 1D NOE, and computer-assisted analysis of 1D 13C NMR spectra. The remaining material after extraction of the biomass with 2-propanol showed to be a lipopolysaccharide with an O-specific polysaccharide chain having a different structure (2), which has been found previously in lipopolysaccharides of a number of other Gram-negative bacteria. [formula: see text]

Antigens, Bacterial↗
PubMed1997

A new glycosylated lipopeptide incorporated into the cell wall of a smooth variant of Gordona hydrophobica.

A cell wall component of a smooth variant of Gordona hydrophobica 1775/15 was isolated and purified, and its structure was determined by various chemical methods, including chemical synthesis of part structures, Edman degradation, gas chromatography/mass spectrometry analysis, matrix-assisted laser desorption ionization-post-source decay (MALDI-PSD) tandem mass spectrometry, and 1H and 13C NMR using one- and two-dimensional, homo- and heteronuclear correlated spectroscopy. The cell wall component was found to be a (mono-) glycosylated peptidolipid (GPL) consisting of a tridecapeptide interlinked by a beta-hydroxylated fatty acid (3-hydroxyeicosanoic acid, 20:0 (3-OH)) to form a cyclic lactone ring structure. The main fraction of GPL, for which we propose the name gordonin, was identified as 3-hydroxyeicosanoyl-L-seryl-L-phenylalanyl-L-seryl- L-seryl-D-alanyl-L -(O-beta-D-glucopyranosyl)-threonyl-glycyl-D-leucyl-L-valyl-L-seryl-L -phenylalanyl-glycyl-L-valyl lactone. The other GPLs constitute structural variations within the nature of the beta-hydroxylated fatty acid (20:0(3-OH) versus 22:1(3-OH)) in a ratio of about 1:0.9 as well as within one amino acid (D-Leu versus L-Phe) in about 30%. Sequence information was obtained in part by Edman degradation as well as gas chromatography/mass spectrometry analysis of di- and tripeptide fragments. However, the complete amino acid sequence could only be established by MALDI-PSD from the linear molecule, i.e. after ring opening of the lactone. In contrast, rough variants of G. hydrophobica 1775/15 lack these peptidolipids or synthesize them to a much lesser extent indicating that gordonin contributes significantly to the physicochemical character of the cell surface.

Actinomycetales↗
PubMed1997

Synthesis, stability, and subcellular distribution of major histocompatibility complex class II molecules in Langerhans cells infected with Leishmania major.

Protozoan parasites of the genus Leishmania exist as obligatory intracellular amastigotes and invade macrophages and Langerhans cells, the dendritic cells of the skin. Langerhans cells are much more efficient in presenting Leishmania major antigen to T cells than macrophages are and have the unique ability to retain parasite antigen in immunogenic form for prolonged periods. To analyze the mechanisms that are responsible for this potency, we defined the synthesis, turnover, conformation, and localization of major histocompatibility complex (MHC) class II molecules in Langerhans cells. Hence, Langerhans cells were pulse-labeled; immunoprecipitation of MHC class II molecules and gel electrophoresis followed. In addition, the subcellular distribution of MHC class II molecules in L. major-infected Langerhans cells was analyzed by confocal microscopy. The results show that (i) newly synthesized MHC class II molecules are required for L. major antigen presentation by Langerhans cells, (ii) MHC class II-peptide complexes in Langerhans cells are long-lived, (iii) phagocytosis of L. major modulates MHC class II biosynthesis by reducing its downregulation during Langerhans cell differentiation, and (iv) newly synthesized MHC class II molecules are associated with the parasitophorous vacuole of infected Langerhans cells. These findings support the conclusion that the traits of MHC class II expression correspond to the highly specialized functions of Langerhans cells in the immunoregulation of cutaneous leishmaniasis.

Animals↗