Zentralblatt für Bakteriologie, Mikrobiologie und Hygiene. Series A: Medical Microbiology, Infectious Diseases, Virology, Parasitology最新文献

LPS-specific monoclonal antibodies induced against Y. enterocolitica serotype O:9 bacteria and against Y. enterocolitica O:3 were used in a comparative study to characterize the O:9 and O:3 LPS. Yersinia bacteria grown at 22 °C and 37°C and LPS preparations thereof were tested. SDS-PAGE, Western blot analysis and adsorption procedures revealed that LPS of Y. enterocolitica O:9 differed from that of Y. enterocolitica O:3 in: (i) its repeating LPS O-side-chain sugar, (ii) its shorter length of the LPS O-side-chain and (iii) its failure to show temperature-dependent variation in the length of O-side-chains.

Zu einer vergleichenden immunologischen Charakterisierung von Y. enterocolitica Serotyp O:9 und O:3 LPS wurden entsprechende monoklonale Antikörper eingesetzt. Als Antigen wurden bei 22 °C und 37°C gewachsene intakte Yersinien, sowie LPS-Präparationen von diesen verwendet. SDS-PAGE, Western-Blot-Analysen und Adsorptionsexperimente zeigten, daß sich das LPS von Y. enterocolitica O:9 von dem von Y. enterocolitica O:3 in (a) seinem LPS O-Seitenkettenzucker, (b) in der Länge der O-Seitenketten und (c) in einer temperaturunabhängigen Länge der O-Seitenketten unterscheidet.

Adhesion studies with cryotome sections of human kidney and lung respectively uroepithelial cells together with blocking experiments with competitive carbohydrates suggested that specific attachment of S. saprophyticus strain S 1 to host cells apparently is mediated by lectins. Accordingly, microbial lectin blocking with specific glycoconjugates or lectin dysfunction (after treatment of bacteria with subinhibitory concentrations of tunicamycin) significantly decreased staphylococcal adherence to epithelial cells. Chemiluminescence measurements of human polymorphonuclear leukocyte (PMN) function yielded results suggesting importance of lectin-receptor interaction in phagocytosis, too, since PMN activity was significantly decreased after staphylococcal lectin blocking or dysfunction.

Adhäsions- und Inhibitionsstudien mit Kryotomschnitten menschlicher Niere und Lunge bzw. mit Uroepithelzellen demonstrierten, daß die spezifische Adhäsion von S. saprophyticus Stamm S 1 an Wirtszellen offensichtlich durch bakterielle Lektine vermittelt wird. Lektinblockade durch rezeptorkomplementäre Kohlenhydrate bzw. Funktionseinschränkung der Lektine (nach Inkubation der Mikroorganismen in subinhibitorischen Konzentrationen des Antibiotikums Tunicamycin) bewirkte eine signifikant reduzierte Adhäsion von S. saprophyticus an die Epithelzellen. Chemilumineszenz-Messungen zeigten, daß Rezeptor-Ligand-Wechselwirkungen auch für den Prozeß der Granulozytenstimulation von Bedeutung sind. Blockade der Staphylokokken-Lektine sowie deren Funktionseinbuße (nach Tuni-camycininkubation) schränkte die Aktivierbarkeit von Granulozyten signifikant ein.

A state of “saturation” of the cell surface ensues when only 5–10% of the cell surface is “covered” by the adsorbed virions. Hence, this state cannot be explained by an “overcrowding effect” caused by the virions attached to the cell surface. A hypothesis of heterogeneity of the cell surface with regard to the virus adsorbtion (“the domain hypothesis”) is suitable for explanation.

Es folgt der Zustand einer “Sättigung” der Zelloberfläche, wenn nur 5–10% der Zelloberfläche von den adsorbierten Virionen “bedeckt” sind. Folglich kann dieser Zustand nicht durch den Effekt einer zu hohen Populationsdichte erklärt werden, der durch die angehefteten Virionen auf der Zelloberfläche verursacht wird. Die Hypothese einer Heterogeneität der Zelloberfläche in bezug auf die Virusadsorption (die “Bereichshypothese”) eignet sich als Erklärung.

Borna disease is an endemic progressive encephalomyelitis of horses and sheep prevalent in central Europe. A wide variety of animal species, ranging from chickens to primates can be infected experimentally with the causative virus, which is only poorly characterized. Furthermore, BD virus-specific antibodies have been detected in sera and cerebrospinal fluids of psychiatric patients.

Our studies on the pathogenesis of BD have shown that — at least in rats — the disease is not caused by the infecting virus itself, but by a virus-induced immunopathological reaction. Thus, after intracerebral infection immunoincompetent rats do not get the disease despite persistent virus replication in cells of the central nervous system. However, after adoptive transfer of immune cells from diseased rats, immunoincompetent rats exhibit full-blown BD. Recently, we have been successful in establishing a virus-specific T cell line of the helper/inducer phenotype (CD4⁺). This T cell was shown to play an important role in the pathogenesis of BD, suggesting that the disease is caused by a delayed type hypersensitivity reaction.

Encapsulated and nonencapsulated Klebsiella strains with different types of fimbriation were tested for their opsonin-dependent stimulation of human polymorphonuclear leukocytes (PMNs). Chemiluminescence (CL) of the PMNs was determined since CL-response can be used indirectly to quantitate phagocytosis. Apparently, the interaction between Klebsiella bacteria and human PMNs is dependent on the type of fimbration and on the presence of capsules. Evaluation of the bactericidal capacity of human PMNs against Klebsiella bacteria positively correlated with the chemiluminescence response demonstrating the importance of fimbriation and capsulation for this process, too.

Bekapselte Klebsiellen-Stämme mit unterschiedlichem Fimbrienbesatz (Stämme ohne Fimbrien, Stämme mit Fimbrien des Types 1 oder 3 und Stämme mit Fimbrien des Types 1 und 3) und ihre nichtbekapselten Mutanten wurden auf ihre (opsoninabhängige) stimulatorische Potenz gegenüber menschlichen Granulozyten untersucht. Vorhandensein oder Fehlen von Fimbrien oder Schleimkapsel trugen entscheidend zur Klebsiellen-Granuloiyteninteraktion bei und manifestierten sich eindeutig im Chemilumineszenz-Test. Der Bakterienabtötungseffekt durch menschliche Granulozyten korrelierte positiv mit den Chemilumineszenzstudien. Kapsel und Fimbrien sowie Fimbrienart hatten Einfluß auf den direkten Klebsiellen-Abtötungseffekt durch Granulozyten.

A toxoid of erythrogenic toxin type A (ET A) was prepared by formaldehyde treatment. Already 15 min after exposure to formaldehyde in isoelectric focusing the ET A band at pH 5.2 shifted to a band at pH 4.5.

In Ouchterlony double diffusion test ET A and its toxoid were found to be identical, in fused rocket immuno-electrophoresis a reaction of partial identity was seen. Formaldehyde treatment of ET A resulted in an apparent increase of electrophoretic mobility. In contrast to ET A, its toxoid is non-mitogenic, non-pyrogenic and has lost its ability to induce delayed type hypersensitivity. Binding of ET A toxoid to human peripheral lymphocytes is of the same magnitude as binding of gold-labelled ET A.

Durch Formaldehydbehandlung wurde aus hochgereinigtem erythrogenen Toxin Typ A (ET A) ein Toxoid hergestellt. Bereits nach 15 min Einwirkung des Formaldehyds trat in der isoelektrischen Fokussierung eine Verschiebung der scharfen ET A Bande bei pH 5,2 zu einer Bande bei pH 4,5 ein. Im Ouchterlony-Test erwiesen sich ET A und sein Toxoid als serologisch identisch, in der Fused-Rocket-Immunoelektrophorese war eine partielle Identität nachweisbar. Die Formaldehydbehandlung des ET A führte in der SDS-PAGE zu einer scheinbar stärkeren elektrophoretischen Mobilität. Im Gegensatz zu ET A ist das Toxoid nicht mitogen, apyrogen und hat seine Fähigkeit zur Induktion einer Hautreaktion vom verzögerten Typ verloren (10 000fache Gewichtsmenge Toxoid im Vergleich zur Minimalmenge des ET A von 5×l0⁻⁷ mg/ml). ET A-Toxoid bindet sich in gleichem Ausmaß an humane periphere Lymphozyten wie goldmarkiertes ET A.

Mycoplasma (M.) mobile 163 K, isolated from the gills of a tench (Tinea tinea L.), was examined for cytotoxic capacities using tracheal organ cultures from gnotobiotic rats and gnotobiotic piglets in pH-controlled experiments (pH 7.2–7.6).

The mycoplasmas caused an inhibition of the ciliary activity at incubation temperatures of 20, 25 and 30°C. The strongest cilia stopping effect was observed at an incubation temperature of 25°C, the optimal growth temperature of the mycoplasmas. No ciliostasis occurred at 37°C. The number of the organisms did clearly affect the severity of ciliostasis in the range from 4.0 × 10⁴ to 7.7 × 10⁸ c.f.u. in rat as well as in porcine tracheal organ cultures. Toxic substances, secreted by the mycoplasmas into the culture medium, could not be detected. In histological investigations cytopathological changes were observed in the epithelial cells, apparent in the destruction and loss of cilia, cytoplasmatic vacuolization, swelling of mitochondria, peripheral orientation of the nuclear chromatin and detachment of epithelial cells from each other and the basal membrane. The final stage of the infection was characterized by complete exfoliation of the epithelial cells and the complete destruction of the multi-layer epithelium. The localization of the mycoplasmas attached to the ciliary epithelium was shown by scanning and transmission electron microscopy.

232 sera and 40 cerebrospinal fluid samples of altogether 125 patients in stages III or IV of a HIV-infection were tested for circulating antigen of Toxoplasma gondii by means of a three-layer enzyme-linked immunosorbent assay. Circulating antigen was detected in 32 sera of 20 patients (= 16% of all persons investigated). These ELISA results were reexamined by an Immunoblot following a SDS-PAGE and confirmed in most cases. In addition, this test system led to a partial characterization of the circulating antigen; it consists of at least two proteins with atomic mass units of 27 and 57 kd respectively.

The antigenemia was correlated with IgG- and IgM-antibody titres, with clinical symptoms, and with pathological findings also. Our results indicate that the detection of circulating antigen in sera offers a rapid and efficient method for the diagnosis of an acute toxoplasmosis in AIDS-patients.

The present study was performed to clarify whether structural proteins are constituants of the antigens of Toxoplasma gondii which circulate in the sera of experimentally infected mice. Rabbits were immunized with mice sera containing circulating antigen, the rabbit sera were then tested for antibodies against Toxoplasma gondii. Low titers of specific antibodies, directed against cell wall proteins, could be detected. Thus, the circulating antigen must at least partially consist of structural proteins.