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Biomedical subjects

G Möller

Publications and source records attributed to G Möller.

At least 127 records · Page 7Linked to original sources
PubMed1987

Subclass restriction pattern of antigen-specific antibodies in donors with defective expression of IgG or IgA subclass heavy chain constant region genes.

We have developed a method for the measurement of the IgG and IgA subclass distribution of antigen-specific human antibodies. The controls for the specificity of the assay include the use of a number of monoclonal human antibodies and sera from individuals with deletions of particular immunoglobulin heavy chain constant region genes. The system was used to determine the shift in immunoglobulin subclass patterns of specific antibodies against a variety of protein and polysaccharide antigens in individuals with a regulatory deficiency of a given IgG or IgA subclass. Normally, the pattern is quite distinct and antibodies against protein antigens are mainly of the IgG1 subclass, whereas antibodies against polysaccharide antigens are mainly of the IgG2 subclass. The results on serum from an IgG1 deficient donor suggested that IgG3 and IgG4 appear to compensate for a lack of IgG1, whereas isolated deficiencies of IgG3, IgG4, or IgA2 do not markedly influence the expected distribution of specific antibodies. In IgG2-deficient individuals a more complex pattern was observed where antibodies against protein antigens were retained, whereas levels of antibodies against polysaccharide antigens could vary markedly between donors, which appeared to be dependent on whether the IgG2 deficiency was an isolated defect or combined with IgG4/IgA deficiency. However, all the IgG2-deficient donors had a skewed pattern of anti-polysaccharide antibodies with a shift to IgG1 to IgG3.

Antibodies↗
PubMed1987

ELISA assay for the detection of a dextran-binding product secreted by a T-cell hybrid Th 1.

When CBA X BALB/c mice are immunized with Th 1 hybrid prepared by fusing spleen cells from Dx-immunized mice with the AKR thymoma BW 5147, which secretes material that affects the anti-Dx response in CBA mice, antibodies are produced that in the ELISA are shown to bind to the material secreted by Th 1 but not to the material secreted by parent BW 5147. A fraction of the Th 1 secreted material that starts eluting on DEAE chromatography in 20 nM Tris with 0.13 M NaCl is shown to bind to Dx but not SRC or uncoated ELISA plates. This binding, like that of anti-Dx Ig, can be inhibited with 1-10 micrograms/ml concentrations of free Dx. However, the affinity of the product of Th 1 for Dx is apparently lower than that of anti-Dx Ig, since high concentrations of anti-Dx interfere with the binding of Th 1 products to Dx. On gel permeation chromatography, a similar Dx binding material elutes in two molecular weight areas, a high area of the molecular weight of IgG and less and a low area of the molecular weight of 43,000 and above, and both are found in samples of Th 1 ascites and hyperimmune CBA anti-Dx serum, but not (or less so) in normal CBA serum and not in the hyperimmune nude C57B1 anti-Dx serum. The Th 1-derived material that affected the anti-Dx response in previously shown experiments had similar elution characteristics. Since we also show that these fractions need not to contain Ig and that anti-Th 1 minimally cross-reacts with anti-Dx IgM or IgG, it is likely that that fraction of Th 1-secreted material represents a Dx-binding, non-Ig, anti-Dx response-regulating factor.

Animals↗
PubMed1987

Purification of an IgM antibody response-enhancing factor to the alpha 1-6 epitope of native dextran from serum and supernatants from T-cell hybridomas.

We have found that some hybrids produced by fusing AKR thymoma BW 5147 with spleen cells from Dx-hyperimmunized CBA mice produce factors that affect the primary CBA IgM PFC response. By the use of HPLC-DEAE chromatography, sometimes combined with affinity chromatography, we have purified from hyperimmune anti-Dx serum, from ascites-growing T hybrids, and from normal CBA serum a family of factors that specifically enhance the anti-Dx IgM response. They show specificity for either Dx or anti-Dx, they may contain an Iak determinant, and they are genetically restricted in their function. The factors from all three sources are found in the same fractions after separation and move in fractions without Ig contamination. The affinity-purified factor was eluted at an NaCl concentration of 0.15-0.20 M. On the basis of these characteristics we believe that we have separated a class of T cell-derived helper factors from serum. The concentration of the factor in serum increases after hyperimmunization with Dx. As a specificity control we show that the same sera contain a natural anti-SRBC IgM response-enhancing factor. It co-separates with the anti-Dx-enhancing factor, but they can be distinguished by their preferential binding to their own antigens.

Animals↗
PubMed1985

Antibody-mediated suppression of the immune response is determinant specific.

It was studied whether antibody-mediated suppression of the immune response was determinant specific. Fluorescein isothiocyanate (FITC)-conjugated sheep red cells were used as the immunogen and antibodies were raised both against the carrier sheep red cells and the hapten FITC. When these antibodies were injected 1-3 h after the immunogen they only suppressed the immune response to the corresponding determinant. Anti-carrier antibodies usually enhanced the response to the hapten. Therefore, antibody-mediated suppression of the immune response is determinant specific and cannot be mediated in vivo to a detectable extent by the Fc part of the antibodies.

Animals↗
PubMed1985

Role of antigen and antibody in the regulation of the immune response.

The enzyme dextranase could degrade antigenic dextran in vivo even when given 6-15 d after the antigen. Dextranase injected after the antigen suppressed the immune response when given 24 but not 48 h after the antigen, indicating that the antigen must interact with the immune system for 48 h to initiate a response. Thereafter, the B cells are independent of further antigen stimulation. To show whether antibody-mediated suppression of the immune response was determinant specific FITC-conjugated SRC were applied as immunogen and antibodies were raised both against the carrier (SRC) and the FITC hapten. When these antibodies were injected 1-3 h after the immunogen they only suppressed the immune response to the corresponding determinant. Anti-carrier antibodies usually enhanced the response to the hapten. Therefore, antibody-mediated suppression of the immune response is determinant-specific and cannot be mediated in vivo to a detectable extent by the Fc part of the antibodies.

Animals↗
PubMed1985

Influence of RU 41.740, a glycoprotein extract from Klebsiella pneumoniae, on the murine system. II. RU 41.740 facilitates the response to Con A in otherwise unresponsive T-enriched cells.

RU 41.740, a glycoprotein extract from Klebsiella pneumoniae, is a polyclonal B cell activator in the thymus-independent category, and both RU 41.740 and its fraction F1 induce the production of interleukin 1 (IL 1). RU 41.740 alone appears to have no direct effect on T-enriched cells. However, we show here that when given in conjunction with concanavalin A (Con A), RU 41.740 enabled nylon wool-passed T cells, which had been accessory cell depleted and lost responsiveness to Con A, to proliferate in response to Con A. Analysis of this observation indicated that RU 41.740 probably acted via a residual accessory cell population and that contact of this cell with the T cell was necessary for Con A activation of the T cell. Because both lectin/antigen and a source of IL 1 are required to stimulate accessory cell-depleted T cells, the mechanism of action of RU 41.740 in this system may be by induction of IL 1 from residual accessory cells in the nylon wool-passed, T-enriched cell population. However, two other agents that stimulate IL 1 production, lipopolysaccharide (LPS) and F1, do not enable T-enriched cells to respond to Con A in this system.

Adjuvants, Immunologic↗
PubMed1984

Role of antigen in the regulation of the immune response to dextran B512.

Dextranase mixed with dextran in vitro or injected into mice before the antigen abolished the immunogenicity of both thymus-dependent and thymus-independent forms of dextran. Dextranase could degrade dextran in vivo even when given 6-15 days after the antigen. Dextranase injected after the antigen suppressed the immune response when given 24 h, but not 48 h, after the antigen, indicating that the antigen must interact with the immune system for 48 h to initiate a response. Thereafter , the B cells are independent of further antigen stimulation. The induction of autoanti -idiotypic anti-dextran antibodies was abolished if dextranase was given 24 h, but not 48 h, after the antigen, indicating that anti-idiotypic antibodies can be induced in the absence of antigen or immune complexes once anti-dextran antibodies have been synthesized.

Antibody Formation↗
PubMed1984

Multicentre study of a new enzymatic method of cholesterol determination.

A new enzymatic method for the determination of cholesterol in serum and plasma was evaluated in 8 separate laboratories in comparison with routine and reference methods. Investigation of the analytical reliability in the 2-26 mmol/l measurement range showed the following results: At the set reading points (10 min at 25 degrees C and 5 min at 37 degrees C) the reaction shows complete substrate conversion. The colour complex is stable over a period of 60 min. The response to cholesterol is linear up to 26 mmol/l. Precision within the series was 0.6-2.8% in 20 determinations (coefficient of variation). Day to day precision was 0.5-3.3% in triple determinations of 10 days (coefficient of variation). Accuracy was studied with 2 samples (assigned value: 3.52 and 6.70 mmol/l respectively). In the case of sample 1 the mean for the 8 laboratories was 3.44, with a median of 3.44; for sample 2 the values were 6.68 and 6.72. The results demonstrate an excellent transferability. In comparison with other enzymatic procedures, the values found with the new test were 5-10% higher; these results agree at all concentration ranges with the reference methods of Abell & Kendall and with those from mass spectrometry.

Cholesterol↗
PubMed1984

Influence of RU 41.740, a glycoprotein extract from Klebsiella pneumoniae, on the murine immune system. I. T-independent polyclonal B cell activation.

A glycoprotein extract from Klebsiella pneumoniae, RU 41.740, has been shown clinically to reduce infectious episodes in patients prone to frequent infections, and experimentally to reduce mortality in animals infected with various bacteria or viruses. The method of action of RU 41.740 in conferring protection from infection is as yet unknown, but in experimental animals, RU 41.740 appears to influence B and T cells as well as macrophages. We report here that RU 41.740 is a strong polyclonal B cell activator and that it activates B cells in a T-independent manner. RU 41.740 also activates spleen cells from the LPS-nonresponder mouse strains, C3H/HeJ and C57BL/10ScCr, which indicates that the polyclonal B cell activating ability of RU 41.740 is not due to contamination by LPS.

Animals↗
PubMed1984

New photometric assay for chymotrypsin in stool.

In this new photometric assay fecal samples are pretreated with detergent and high concentrations of salts. The subsequent kinetic enzyme determination step involves the chromogenic substrate succinyl-Ala-Ala-Pro-Phe-4-nitroanilide. The sample pretreatment assures a nearly complete solubilization of the formerly particle-bound enzyme, thus permitting determination of the enzyme activity in either the suspension or the supernate after centrifugation. Furthermore this pretreatment enhances the enzyme activity and decreases the Km value. Results by this assay correlate well with those by classical titrimetry and the method is easily adapted to automated systems.

Autoanalysis↗
PubMed1983

Mechanism of unresponsiveness to the alpha 1-6 epitope of dextran B512 in a C57BL substrain.

C57BL/10ScCr mice are low responders to the alpha 1-6 epitope of dextran B512, although other C57BL mice are high responders. Both thymus-independent and thymus-dependent forms of dextran failed to induce an immune response in C57BL/10ScCr mice, but dextran functioned as a good carrier for antihapten responses in this strain. Dextran is a potent polyclonal B cell activator for cells from C57BL/10ScCr mice, although such cells are not activated by LPS. The C57BL/10ScCr mice possess the Igh-V gene coding for antibodies against dextran and the antidextran antibodies induced in (A X C57BL/10ScCr)F1 hybrids share an idiotype with antidextran antibodies produced in C57BL/10 mice. Bone marrow cells from C57BL/10ScCr mice do not respond to dextran when transferred into lethally irradiated C57BL/10 mice and C57BL/10 cells transferred into C57BL/10ScCr mice give a strong antidextran response. Thus, B cells having both the Igh-V gene coding for antibodies against dextran and activation receptors for dextran cannot be activated into antibody synthesis against any form of this immunogen. This determinant specific immunodeficiency suggests the existence of as yet unknown regulatory influences on Igh-V gene expression or B cell activation.

Animals↗
PubMed1983

Immune responses to xanthan gum. I. The characteristics of lymphocyte activation by xanthan gum.

Xanthan gum (XG), a microbial polysaccharide produced extracellularly by fermentation of Xanthomonas campestris, has unique physical properties. We studied the effects of XG on murine lymphocytes in vitro and found that XG induced both a significant increase of DNA synthesis in mouse splenic B cells and thymocytes as well as polyclonal IgM and IgG antibody responses in B cells. XG-activated thymocytes, however, did not display helper or suppressor functions. XG was almost as effective in inducing polyclonal antibody responses as lipopolysaccharide (LPS) in murine systems. Hamster spleen cells, however, were weakly triggered to nonspecific antibody production by XG but they were not triggered at all by LPS. Spleen cells from normal neonatal mice and from adult CBA/N mice, a strain which possesses an X-linked defect affecting B cell differentiation, responded relatively well to XG and LPS, suggesting that XG can stimulate immature B cells as well as LPS does. It was found that XG activated B cells in the relative absence of T cells and macrophages. Spleen cells from LPS-nonresponder C3H/HeJ mice and seven other mouse strains were stimulated to polyclonal antibody production by XG. In contrast, spleen cells from C57BL/10 mice were unresponsive or only slightly responsive to XG, but fully responsive to LPS.

Animals↗
PubMed1983

Activation of BCL1 cells by polyclonal activators and inhibition of growth and IgM secretion by anti-IgM.

Bacterial lipoprotein (LP) and lipopolysaccharide (LPS) both activated an in vitro line of the B-cell tumour BCL1 to IgM secretion, as determined by the protein A plaque assay. LPS but not LP activation was inhibited by polymyxin B. Activation with both LPS and LP resulted in a less than additive response. Several clones of BCL1 were tested, and all responded to both LPS and LP. Both LPS and LP induced broad dose-response curves in normal lymphocytes, recently cloned BCL1 cells, and cloned and synchronized (G1 phase) BCL1 cells. This suggests that the dose-response curve cannot be due to accumulation of responding cells with different threshold sensitivities for activation. We cannot exclude the possibility that the broad dose-response curve is due to a heterogeneity of the LPS or LP preparation. The results indicate that LPS and LP induce similar signals in BCL1 cells. Furthermore, binding to the cell membrane and activation of BCL1 cells by LPS or LP seem to be separate events. An anti-IgM antiserum inhibited spontaneous DNA synthesis and spontaneous and LP-induced IgM secretion of BCL1 cells. Equal inhibition was observed with F(ab')2 fragments but not with Fab fragments of the antiserum, suggesting that cross-linking of IgM bound to the cell surface membrane-induced inhibition. Supernatants from concanavalin A (Con A)-activated spleen cells induced BCL1 cells to secrete IgM. Fab anti-IgM added alone to BCL1 cells did not induce IgM secretion. Furthermore, Fab anti-IgM plus Con A supernatant did not induce a higher response than the supernatant alone. This suggests that inductive signals via the IgM receptor do not occur in BCL1 cells.

Animals↗