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U Rother

Publications and source records attributed to U Rother.

At least 55 records · Page 3Linked to original sources
PubMed1984

Freeze-thaw activation of the complement attack phase: II. Comparison of convertase generated C--56 with C--56 generated by freezing and thawing.

The activation of the C-attack phase does not necessarily involve the components of the C5 convertases. C--56 hemolytic activity was generated from the same source of C7 depleted serum by the alternative pathway convertase or by freezing and thawing resp. In contrast to activation by the convertase, biological activities of C5a (chemotaxis, serotonin release) were not detected following activation by freezing. The yields of C--56 hemolytic activities were similar and the properties of the activated products were identical. No difference was found in the molecular weight, in the hydrophobicity or with respect to charge. The two activities were in the absence of C7 stable at 37 degrees C and decayed rapidly in the presence of C7. It is proposed that a conformational change in the tertiary structure of the molecule(s) is the critical event in the formation of an active C--56 complex. In this light the cleavage of C5a from the native molecule by the convertase appears as a side reaction, not by itself essential for activation.

Complement Activating Enzymes↗
PubMed1984

Freeze-thaw activation of the complement attack phase: I. Separation of two steps in the formation of the active C--56 complex.

The activation of the attack phase of C, C5-C9, is generally assumed to be dependent on the enzymes of the C activation pathways which cleave C5 into C5b and C5a. C5b will then form a complex with C6 that binds to membranes and, in the presence of C7-C9, effects cell lysis. In contrast, however, a variety of physicochemical means was found to activate C5 + C6 independently of the convertases and without apparent generation of the C5a peptide. By freezing and thawing of C5 + C6 a hemolytic C--56 activity was generated: (C--56 ).f The activation proceeded in two steps: (1) during a preincubation period of the two components the time and temperature dependent formation of an activatable intermediate was observed and (2) the intermediate C--56 could then be endowed with hemolytic activity by freezing and thawing. The intermediate as well as the activated (C--56)f complex was separated from C5 and C6 by anion exchange chromatography. While the isolated intermediate was labile, the active product after freezing and thawing was stable.

Complement Activation↗
PubMed1983

Lysis of paroxysmal nocturnal hemoglobinuria erythrocytes by acid-activated serum.

Erythrocytes from paroxysmal nocturnal hemoglobinuria patients (PNH-E) are much more susceptible to lysis by acid-activated human serum than normal human erythrocytes. Acidification of normal human serum to pH 6.4 in the absence of erythrocytes generates this lytic activity independently of the alternative pathway of complement activation. A shift of pH of a mixture of purified human C5 and C6 to 6.4 at 0 degrees C generates a similar activity C(56)a that lyses PNH-E together with C7-C9 much more efficiently than normal erythrocytes. Since acid-activation of normal human serum occurs in the absence of C3, the acid-activated C56 appears to be the lytic principle in acidified human serum.

Animals↗
PubMed1983

C5a-induced chemiluminescence of human granulocytes and its amplification by a serum factor.

Purified human C5a elicits a fast chemiluminescence (CL) response from isolated human granulocytes in the presence of Lucigenin (bis-N-methylacridinium nitrate). The reaction is inhibitable to more than 90% by superoxide dismutase (SOD) - final concentration 200 micrograms/ml -, to about 60% by catalase - final concentration 10 mg/ml - and to 30% by the hydroxyl radical scavenger D-mannit - final concentration 100 mM. Therefore O2- seems to be the oxygen radical responsible for most of the CL, while OH and H2O2 are also involved. Addition of normal pool serum to the cells for 1-2 min before stimulation with C5a strongly enhances the effect in a dose and time-dependent manner. Therefore the existence of a "helper activity" in serum amplifying the C5a-induced CL of granulocytes is postulated. This "helper activity" is, however, no specific for C5a, since CL responses elicited with the chemotactic peptide f-met-phe or by phorbol-myristate-acetate (PMA) are also enhanced by preincubation with serum. In contrast, ConA-induced CL is not enhanced but decreased. Therefore, though not unique to C5a-induced CL, the "helper activity" seems not to represent a general "adjuvans" effect of serum on the granulocytes, but to be restricted to certain stimuli.

Chemotaxis, Leukocyte↗
PubMed1983

The fifth component of complement (C5): purification without activation.

In the course of our studies on the structural change of C5 by acidification (U. Rother et al., 1978), we found that the C5 preparations purified according to published methods contained more or less activated C56. When added to sensitive target cells (guinea pig or chicken erythrocytes), C5 mediated lysis by C7-C9 without the addition of C6 or any activation procedure. Generation of C56 was probably due to drastic changes in the physicochemical environment during purification. Such changes like high or low pH or high ionic strength were shown to cause activation. A method for purification of C5 is described in which polyethyleneglycol (PEG) or (NH4)2SO4 precipitation, as well as low or high pH, was avoided. As a last step, traces of C6 were removed by affinity chromatography. The resulting preparation was free of C56. Activation by acidification was not possible without the addition of C6. The total recovery of C5 was 12% with almost no loss of specific activity.

Animals↗
PubMed1983

Glycophorin A inhibits lysis by the complement attack phase.

A glycoprotein from human erythrocyte membranes has been found to inhibit lysis of target cells by the attack-phase components C5-C9 from human complement. The inhibiting molecule was purified and identified as glycophorin A. Thus, glycophorin A may have a regulatory function in the lytic complement attack on isologous cells.

Animals↗
PubMed1983

Schistosoma mansoni: complement activation in human and rodent sera by living parasites of various developmental stages.

Living Schistosoma mansoni of various developmental stages were studied with respect to their ability to activate the complement system in sera of humans, mice and rats. Immunofluorescence assays demonstrated that binding of human C3 occurred on fresh schistosomula as well as on schistosomula prepared from mouse lymph-nodes or lungs and on adult schistosomes. However, rodent C3 was deposited only on fresh schistosomula. Deposition of human C3 on the worms' surface required activation of the complement system. The alternative pathway was shown to be involved in deposition of human C3 on schistosomes of all ages, whereas activation of the classical pathway was demonstrable only with fresh schistosomula. Immunoelectrophoretic studies demonstrated a dose-dependent cleavage of human C3 and conversion of factor B by living adult schistosomes. The results demonstrate that the ability of living schistosomes to activate complement in vitro is dependent not only on their development stage but also on the species of the serum.

Animals↗
PubMed1982

A new screening test for C3 nephritis factor based on a stable cell bound convertase on sheep erythrocytes.

C3 nephritis factor (C3nef) activity was measured by the incubation of sheep erythrocytes with a mixture of normal human serum and patient's serum in EGTA followed by lysis of the washed cells with rat C in EDTA. The C convertase activity on the cells was dependent on the dose of patient's serum. Activation of human C3-C9 by the washed cells was shown by lysis of susceptible target cells (chicken erythrocytes). The test is specific for C3nef.

Animals↗
PubMed1982

Effect of spleen exposure to ultrasound on cellular and antibody-mediated immune reactions in man.

Spleen exposure to ultrasound has been reported to influence antibody response to sheep red blood cell injection in mice (decreased hemagglutination and hemolytic titers and IgM, IgG2a and IgG2b levels and elevated IgG1 levels). In a controlled clinical trial, we investigated the possible immunosuppressive side-effect of splenic exposure (2.0 mW/m2, 3.5 MHz, 5 minutes) to ultrasound on the immune response to Rubella vaccination in 41 anti-Rubella antibody-negative volunteers. The measured parameters (blood cell count, IgA, IgM, IgG including subclasses IgG1-IgG4, isoagglutinins, anti-Rubella hemagglutinin and hemolysin titers, complement C3, skin tests to mumps and tuberculin, T, B and O lymphocytes, esterase-positive and negative T-cell subsets) suggest changes dependent on the time of vaccination, but provide no evidence of an immunosuppressive effect of ultrasound in man.

Adolescent↗
PubMed1982

Schistosoma mansoni: development of primary infections in mice genetically deficient or intact in the fifth component of complement.

The influence of the late components of complement (C) on the percutaneous primary infections with Schistosoma mansoni was studied in inbred mice genetically deficient or intact in C5. Worm recoveries were diminished in C5-deficient male mice as compared to C5-intact animals. Twenty-four-day-old parasites were also shorter following growth in C5-deficient animals. At 7 weeks after infection, female schistosomes, but not male parasites, were shorter and fewer eggs/schistosome pair were deposited in the livers of C5-deficient as compared to C5-intact male mice. In addition to the presence of C5, the mouse sex was found to influence the outcome of an infection. Schistosomes showed a reduced infection rate and were relatively stunted after 24 days of growth in female mice in the two strains as compared to male mice of the corresponding strains. The results suggest that C5 plays no role in defence against a primary infection in mice.

Animals↗