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Biomedical subjects

O Tönder

Publications and source records attributed to O Tönder.

At least 19 recordsLinked to original sources
PubMed1988

Plasma exchange in myasthenia gravis: changes in serum complement and immunoglobulins.

Serum concentrations of C4, IgG, IgA, and IgM were followed in 8 selected patients with myasthenia gravis (MG) during a 5-day course of plasma exchange (PE), using donor plasma as a replacement solution. C3 activation products (C3b, iC3b and C3c) and the terminal SC5b-9 complement complex were measured in 4 of the patients. All patients improved during the treatment, including 2 patients without detectable antibodies to AChR in serum. The main findings of the study were marked complement activation and an approximately 50% fall in the serum concentrations of IgM and C4 during PE, independent of the concentrations in the donor plasma. The concentrations of IgG and IgA did not change significantly. The fall in C4 during PE is presumably caused by C4 consumption. We postulate that the fall in IgM is an effect of a complement-induced vasodilatation and that PE-induced complement consumption may influence the effect of PE in patients with MG.

Adult↗
PubMed1986

Plasma exchange in myasthenia gravis: effect on anti-AChR antibodies and other autoantibodies.

Plasma exchange (PE) was performed in 6 patients with myasthenia gravis (MG). Acetylcholine receptor (AChR) antibodies and other MG-correlated antibodies were quantified each day before, during and after PE. The antibody concentrations decreased during PE with a consisting increase between two exchanges. Repeated PE induced a transient decline in the AChR antibody concentration. The clinical improvement was maximal during the week after PE and correlated in time with increasing concentrations of AChR antibodies.

Adult↗
PubMed1985

Hassall's corpuscles in the thymus of fetuses, infants and children: immunological and histochemical aspects.

Hassall's corpuscles (HC) were examined for immunological and histochemical markers in cryostat sections of thymus from fetuses, infants and children. HC could not be detected before 14 weeks of gestation. Receptors for the Fc part of IgG (Fc gamma R) were demonstrated by adherence of ox erythrocytes sensitized with anti-ox IgG using a closed chamber technique. Fc gamma R were also detected by immune complexes of horseradish peroxidase (HRP) and rabbit antibodies to HRP, and with an anti-Fc gamma R serum, using indirect immunofluorescence technique and indirect immunoperoxidase technique. The staining was seen along the outer cell membranes of the HC. The Fc gamma R activity was highest in early fetal life, and decreased with increasing age. Indicator cells which detect receptors for the Fc part of IgM and for the activated third component of complement did not adhere to HC. At 14 weeks of gestation, HC showed a weak alpha-naphthyl acetate esterase (ANAE) activity, while from 16 weeks the staining intensity and pattern was unchanged. In some HC, separate cells with strong ANAE activity were seen. These cells also showed endogenous peroxidase activity, and were stained by an antibody to HLA-DR antigens. Such cells were not seen until 16 weeks of gestation. HC were stained by antibodies to IgG in fetuses older than 16 weeks, and the intensity increased gradually up to 24 weeks. Antibodies to IgM weakly stained some HC in fetuses between 16 and 36 weeks of gestation, whereas antibodies to IgA stained a minority of HC in fetuses older than 24 weeks.

Age Factors↗
PubMed1984

Localization of the binding site on IgG for solubilized placental Fc gamma receptor.

Placental Fc gamma R (FcR) inhibited the rosette formation between monocytes and rabbit IgG-sensitized erythrocytes (EA), whereas the rosette formation with granulocytes was not impaired. Staphylococcal protein A (SpA) inhibited the rosette formation with both cell types. Results obtained in absorption and agglutination experiments showed that SpA blocked the binding of FcR to IgG, and Cl did not. Furthermore, FcR did not interfere with the binding of SpA to IgG, whereas C1 affected this binding. FcR apparently bind to the C gamma 3 region. Since FcR inhibited the binding of EA to monocytes, the monocyte FcR binding site is probably also located within the C gamma 3 region.

Binding, Competitive↗
PubMed1984

A monoclonal antibody inhibiting human placental Fc gamma-receptor activity.

Fc gamma receptor (FcR) from human placenta was solubilized using EDTA and 2-mercaptoethanol and purified by affinity chromatography on human IgG-coated Sepharose 4B. BALB/C mice were immunized with FcR and monoclonal antibodies were obtained by growing hybridoma cells following fusion of spleen cells with P3 X 63Ag8 myeloma cells. Using an immunofluorescence technique, the IgG1 monoclonal antibody secreted by clone B1D6 stained the FcR-positive areas in sections of placental tissue. The endothelium of the foetal stem vessels stained more strongly than did the trophoblasts. The antibody also inhibited the haemadsorption to placental tissue of erythrocytes (E) sensitized with IgG antibodies (A), (EA), and inhibited the agglutination of EA by FcR. The data indicate that the monoclonal antibody reacts with the placental FcR at the binding site for IgG, or with an epitope close to the binding site. Apparently, the FcR in different anatomical areas in the placenta have a common antigenic determinant.

Antibodies, Monoclonal↗
PubMed1983

Stage-related correlations between immunoglobulins and complement components in preoperative sera from patients with gastric carcinoma.

Immunoglobulins A, G and M and complement components C3, C4 and C1-INH were quantitated in sera taken preoperatively from 168 patients with gastric carcinoma. The values were grouped according to stages (pTNM). The concentrations of C4 and C1-INH increased with advancing stage of disease and were above normal mean values in all stages. The concentration of IgG was below the normal mean value among all the patients and with the lowest concentration in stage III. Concentrations of IgA and C3 were above normal means but without significant relation to stages. There was a positive correlation between the concentrations of IgG and C1-INH in sera from patients with stage IV carcinoma, while the same correlation was negative in stages I-III. Although the results varied among the patients within each stage, the profiles of immunoglobulin and complement concentrations are of value in the preoperative staging of the disease.

Adult↗
PubMed1982

Technical aspects of rosette tests for the demonstration of lymphocyte subpopulations.

Lymphocytes from heparinized or defibrinated blood were separated on Lymphoprep and washed in phosphate-buffered saline (PBS) or Hanks' balanced salt solution (HBSS). Defibrination caused a decreased yield of lymphocytes compared to heparin treatment. The cell loss was probably non-selective, as only minor differences in lymphocyte subpopulations were found. However, lymphocytes from defibrinated blood, washed in PBS gave a lower percentage of rosette-forming cells (RFC) in most tests, and higher number of latex-phagocytizing cells. For the stabilization of sheep erythrocyte (E)-RFC, treatment of E with 2-amino-ethylisothiouronium bromide hydrobromide (AET), with addition of fetal calf serum (FCS), and E-RFC without FCS fixed with glutaraldehyde gave similar results, and higher percentages of RFC than the RFC test performed with FCS. Storage of whole blood or separated lymphocytes for 24 h at 4 degrees C generally resulted in a reduction in the percentages of E-RFC, particularly active E-RFC, but not of EA- or EAC-RFC. The ranges of the results were usually wider after storage.

Cell Separation↗
PubMed1982

The ontogeny of immunological receptors in the thymus.

Receptors for sheep erythrocytes, for the Fc part of IgG (Fc gamma R) and IgM (Fc mu R), and for components of activated human complement C3 (C3bR and C3dR) in thymus tissue from fetuses, infants and children were studied using haemadsorption to cryostat sections in a closed chamber. Sheep erythrocytes (SE) did not adhere to sections of thymus from fetuses at 10-11 weeks of gestation, adhered weakly between 14 and 20 weeks, while they adhered in a dense monolayer in older fetuses, in infants and in children, denser in the cortex than in the medulla. Ox erythrocytes (OE), sensitized with IgG to demonstrate Fc gamma R, adhered focally to both cortical and medullary areas. The adherence was more pronounced to the sections of fetal thymus than to the sections from infants and children. OE, sensitized with IgM to demonstrate Fc mu R, adhered focally to all thymus tissue sections, preferentially to the cortex. The adherence was most pronounced in fetal thymus. SE, sensitized with IgM and coated with complement, adhered to sections of fetal thymus, but the density decreased markedly during fetal life. Indicator cells demonstrating C3bR adhered focally also to sections from infants and children, while indicator cells demonstrating C3dR did not adhere to sections from individuals older than 38 weeks of gestation. Indicator cells demonstrating C3bR and C3dR adhered both to cortex and medulla.

Animals↗
PubMed1982

Properties of the solubilized placental receptor for IgG.

The Fc receptor activity in placental extracts prepared using EDTA and 2-mercaptoethanol was assayed using an indirect hemagglutination technique with sheep erythrocytes sensitized with rabbit IgG. The agglutinating activity of the extract was not affected by storage at -70 degrees C, by rapid freezing and thawing, by treatment with periodic acid, formaldehyde, neuraminidase, trypsin, pronase, or phospholipase C. Papain abolished the activity, indicating that the receptor is a protein. Reduction and alkylation had no effect on the agglutinating activity, indicating that -S-S-bonds are not important for binding. In the presence of 0.6 M NaCl the agglutinating activity was abolished, indicating that electrostatic interactions are of significance. The solubilized Fc receptor shows so many similarities to the previously studied in situ Fc receptor that they are probably identical.

Animals↗
PubMed1981

Thymoma-specific antibodies in sera from patients with myasthenia gravis demonstrated by indirect haemagglutination.

An indirect haemagglutination technique for the demonstration of antibodies to skeletal muscle is described. Eight out of 9 sera from unoperated myasthenia gravis (MG) patients with thymoma and 6 out of 22 sera taken from MG patients who had been operated upon for a thymoma, contained antibodies to this antigen. Twenty-five sera from MG patients with histologically verified thymus hyperplasia did not contain such antibodies. There was no relationship between these antibodies and antibodies to acetylcholine receptor.

Autoantibodies↗
PubMed1981

Isolation and characterization of Fc gamma receptors from human placenta.

Placental extract was prepared with Tris-HCl buffer pH 7.4 containing EDTA and 2-mercaptoethanol. It agglutinated erythrocytes (E) sensitized with subagglutinating amounts of IgG antibodies from rabbits, guinea pigs and mice, but not E sensitized with IgG from chickens. E or E sensitized with F(ab)2 or IgM antibodies were not agglutinated. The agglutination of EA by the extract was inhibited by human, rabbit and guinea pig IgG, but not by bovine and porcine IgG. Aggregated IgG was more inhibitory than monomeric IgG. IgG3 was the most effective subclass. The extract inhibited the formation of EA rosettes with human mononuclear cells, but did not influence the formation of E or EAC rosettes. The significance of the disulfide bonds and the C gamma 3 and C gamma 2 regions was implied by the finding that the extract neither agglutinated E sensitized with preparations of mildly reduced and alkylated IgG, nor with Facb fragments. These preparations did not inhibit the agglutination. The results strongly indicated that the active component was solubilized placental Fc receptor (FcR). Functionally active FcR was purified by affinity chromatography using aggregated human IgG coupled to Sepharose 4B. SDS-PAGE if the purified FcR under reducing conditions showed one distance band corresponding to approx. 47,000 daltons. The band neither consisted o Ig fragments nor Clq. A rabbit antiserum against the FcR inhibited the agglutination of EA by the extract and stained th FcR-positive areas in placenta.

Chromatography, Affinity↗
PubMed1981

Similarities of C3b receptors in human kidney and spleen.

Receptors for C3b (C3R) in human spleen and kidney were studied using haemadsorption to cryostat sections. The indicator cells, ovine erythrocytes (E) coated with rabbit IgM antibody (A) and human C3b (EAC) adhered strongly to the glomeruli in renal tissue and to the white pulp of spleen. Titration experiments showed that avidity of the two populations of C3R was equal. Activity was independent of Ca++ and Mg++. Periodic acid, formaldehyde, high salt concentrations and trypsin abolished, whereas neuraminidase enhanced the activity. Various temperatures and pHs affected the two populations of C3R similarly. The results obtained indicate that the C3R in spleen and kidney are similar.

Animals↗
PubMed1980

A simplified method for the preparation of EAC14.

Sheep erythrocytes (E), sensitized with unheated rabbit antiserum containing IgG antibodies (EA), bound human C4 when heat-inactivated serum was used as the source of complement (EAC). The EA were not agglutinated by antiserum to rabbit C3 and were not lysed in the presence of C4-deficient guinea pig serum. The EAC were agglutinated by antiserum to human C4, lysed by the addition of C4-deficient serum and were reactive in immune adherence. They were not agglutinated by antiserum to human C3. Accordingly, the cells could be designated as EAC14. They were stable and could be stored at 4 degrees C for at least 1 week without haemolysis occurring, and with no loss of reactivity in immune adherence test. E sensitized in the presence of EDTA or with heat-inactivated rabbit serum did not bind C4.

Animals↗
PubMed1980

An improved method for the detection of human T lymphocytes in tissue sections.

The technique of haemadsorption to tissue sections for the detection of T lymphocytes is described in detail. The modification using the closed chamber technique is convenient, sensitive and reproducible. In principle, it parallels the rosette technique using blood lymphocytes in suspensions and AET-treated sheep erythrocytes. Storage of tissue at -25 degrees C did not reduce the activity of the E-receptors in the tissue. The E-receptors were blocked by incubation of the tissue sections with an anti-T lymphocyte serum.

Child↗
PubMed1980

IgG and other proteins associated with human carcinomas and cancer-free tissue from the same organs.

Eluates of different were prepared at 56 degrees C using a continuous flow technique. More IgG and other serum proteins were found in liver from patients with non-malignant diseases than in liver tissue from healthy control individuals. Cancer-free liver tissue from patients with carcinomas was similar to that of patients with non-malignant diseases, but liver metastases contained twice the amount of IgG. No differences were found between non-perfused carcinomas of the kidney and cancer-free renal tissue, whereas more IgG was present in perfused carcinomas of the kidney than in cancer-free renal tissue. Most eluates of the malignant tissues and of the cancer-free renal tissue showed a reduced ratio of albumin IgG compared to that of serum or extracts, indicating a binding of IgG to antigens and/or receptors.

Blood Proteins↗
PubMed1980

C4 receptors in the human glomeruli.

Glomeruli in cryostat sections of human renal tissues adsorbed sheep erythrocytes sensitized with the fourth component of human complement (C). The receptors had specificity for the C4b fragment of C4, and were uniformly distributed in the glomeruli. The receptors were sensitive to trypsin and to periodic acid and were blocked in vivo and in vitro by C3 and C4. Receptors in fetal and adult renal tissues and in areas outside in vivo deposits of C in biopsy specimens had similar avidity. Further results suggested that the receptors for C4b are identical to the receptors for C3b, or that the receptors are located on closely related structures.

Complement C3↗
PubMed1979

Lymphocyte subpopulations in thymus and blood from patients with myasthenia gravis.

Cell suspensions were prepared from hyperplastic thymic tissue and lymphoepithelioma from patients with myasthenia gravis and from presumed normal thymic tissue obtained at cardiac surgery. The mononuclear cells were examined for surface markers. The mean percentages of both T lymphocytes and Fc receptor-carrying lymphocytes were similar in the three groups, whereas there was an increase in C receptor-carrying lymphocytes in the samples from myasthenic patients. Sections from the thymus gland were examined for T and B markers. In the hyperplastic thymus and in lymphoepithelioma, the T lymphocytes were distributed diffusely throughout the cortex and the medulla; in the normal thymus they were predominant in the cortex. The mean percentage of T and B lymphocytes in peripheral blood from patients with myasthenia gravis was normal. Thymectomy involved a transitory decrease in T lymphocytes with a corresponding increase in B lymphocytes.

B-Lymphocytes↗