| 1. |
- Babiker-Mohamed, H, et al.
(författare)
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Characterization of monoclonal anti-alpha 1-microglobulin antibodies : binding strength, binding sites, and inhibition of lymphocyte stimulation
- 1991
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 34:5, s. 655-666
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Tidskriftsartikel (refereegranskat)abstract
- Eleven monoclonal antibodies (MoAb) directed against the immunoregulatory plasma glycoprotein alpha 1-microglobulin were characterized. The MoAb were produced in mice immunized with a mixture of alpha 1-microglobulin homologues from man, guinea pig, rat and rabbit. Using radioimmunoassay, western blotting, affinity chromatography, and Scatchard analysis, the affinities and binding sites of the MoAb were analysed. All antibodies were more or less cross-reactive, but most showed a major specificity for one or two of the alpha 1-microglobulin homologues. None of the antibodies was directed against the carbohydrate moiety of alpha 1-microglobulin. Six of the MoAb had high affinity for the antigen and four of these were directed towards the same part of the molecule though differing in their species specificity. Five showed lower affinity for the antigen and were mainly directed towards epitopes on other parts of the molecule. Only some of the antibodies could block the proliferation of lymphocytes induced by human alpha 1-microglobulin. The blocking efficiency of the different antibodies was similar when tested on the stimulation of human or mouse lymphocytes, suggesting that the same part of the alpha 1-microglobulin molecule is responsible in both species. The magnitude of blocking by the different MoAb was not related to their affinities, emphasizing the importance of where on the alpha 1-microglobulin molecule, rather than how strongly, they bind. The binding of the strongest blocking antibody was shown to be directed to a C-terminal peptide of rat alpha 1-microglobulin, indicating that this part of alpha 1-microglobulin is important for the mitogenic effects. Thus the panel of anti-alpha 1-microglobulin MoAb should be a valuable tool for structural and functional studies of alpha 1-microglobulin.
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| 2. |
- Babiker-Mohamed, H, et al.
(författare)
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Mitogenic effect of alpha 1-microglobulin on mouse lymphocytes. Evidence of T- and B-cell cooperation, B-cell proliferation, and a low-affinity receptor on mononuclear cells
- 1990
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 32:1, s. 37-44
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Tidskriftsartikel (refereegranskat)abstract
- Human alpha 1-m microglobulin (alpha 1-m), a low molecular weight plasma protein, was found to exert mitogenic effects on mouse lymphocytes from lymph nodes and spleen. The stimulatory effects appeared to be strain-restricted: alpha 1-m induced a varying degree of proliferation of lymphocytes from three strains, whereas one strain responded poorly. Experiments with lymphocyte subpopulations showed only weak stimulatory effects of alpha 1-m on purified T and B lymphocytes cultivated alone. The addition of mitomycin-treated cells of the other subpopulation could not restore the proliferative responses in either T or B lymphocytes. Strong stimulations were recorded only when both T and B lymphocytes were present, indicating that the T and B lymphocytes cooperate to achieve the proliferation. However, FACS studies on cultured splenocytes indicated that the proliferating cells are predominantly B lymphocytes. These data extend our earlier findings of a mitogenic effect of alpha 1-m on guinea pig lymphocytes. Furthermore, results were obtained indicating the presence of a receptor on mononuclear cells. Iodine-labelled alpha 1-m was bound to mononuclear cells prepared from spleens, and the binding could be blocked by an excess of non-labelled alpha 1-m. Scatchard plotting of the data gave an equilibrium constant of 0.7 x 10(5)/M for the binding between alpha 1-m and the receptor. Together with the documented inhibitory activity of alpha 1-m on antigen-driven proliferation of lymphocytes, these results suggest an immunoregulatory role for alpha 1-m.
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| 3. |
- De Château, M, et al.
(författare)
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On the interaction between protein L and immunoglobulins of various mammalian species
- 1993
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 37:4, s. 399-405
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Tidskriftsartikel (refereegranskat)abstract
- Protein L, a cell wall molecule of certain strains of the anaerobic bacterial species Peptostreptococcus magnus, shows high affinity for human immunoglobulin (Ig) light chains. In the present study protein L was tested against a panel of human myeloma proteins of the IgG, IgM, IgA and IgE classes, and strong binding was seen with antibodies carrying kappa light chains. A high degree of specificity for Ig was demonstrated in binding experiments with human plasma proteins. Apart from human Ig, strong protein L-binding activity was also detected in the serum of 12 out of 23 tested additional mammalian species, including other primates and rodents. Subsequent analysis with purified Ig samples demonstrated the binding of protein L to Ig of important laboratory animal species such as the mouse, the rat and the rabbit. The affinity constants for the interactions between protein L and polyclonal IgG of these species were 2.6 x 10(9), 3.9 x 10(8) and 7.4 x 10(7), respectively. In non-human species, the binding of protein L was also found to be mediated through Ig light chains, and the results demonstrate the potential value of protein L as an immunochemical tool.
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| 4. |
- HEDGES, S., et al.
(författare)
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Cyclosporin A does not Inhibit IL‐lα‐Induced Epithelial Cell IL‐6 Secretion
- 1993
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 37:5, s. 581-586
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Tidskriftsartikel (refereegranskat)abstract
- Trauma and infection activated a murine mucosal IL‐6 response in different ways: the IL‐6 response to bacteria was sensitive to Cyclosporin A (CsA); the IL‐6 response to trauma was not. The aim of the present study was to identify possible activators of the CsA‐insensitive IL‐6 secretion at the epithelial cell level. Two human epithelial cell lines from the kidney (A498) and bladder (J82) were exposed to Escherichia coli Hu734, interleukin‐lα (IL‐lα) and tumour necrosis factor a (TNF‐α). The E. coli strain had been used for the in vivo experiments which led to this study, and IL‐lα and TNF‐α were likely to be released during infections and trauma. The secretion of IL‐6 into the supernatants was compared between cells stimulated in the presence or absence of CsA. E. coli Hu734, IL‐lα and TNF‐α stimulated an IL‐6 response in the two epithelial cell lines. The IL‐lα‐induced IL‐6 response was rapid, and the secreted IL‐6 levels were significantly higher than those induced by E. coli Hu734 or TNF‐α. The IL‐6 response to IL‐ lα was insensitive to CsA. By contrast, the IL‐6 response to E. coli Hu734 and TNF‐α was inhibited by CsA. These results demonstrated that the inhibitory effect of CsA depends on the stimulus triggering the IL‐6 response. IL‐lα may play a role in the induction of trauma‐associated CsA‐insensitive IL‐6 secretion.
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| 5. |
- Källberg, E, et al.
(författare)
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Kinetics of somatic mutation in lymph node germinal centres
- 1994
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 40:5, s. 80-469
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Tidskriftsartikel (refereegranskat)abstract
- Somatic mutation activity in immunoglobulin V kappa genes during the response to the hapten 2-phenyl-5-oxazolone was measured in lymph node B-cell populations at various timepoints after footpad immunization. When the V kappa Ox1 genes rearranged to the J kappa 5 segment were amplified from genomic DNA using the polymerase chain reaction and sequenced, somatic mutations could be detected as early as day 4 after immunization. Somatic mutations were also detected after sequencing RNA from oxazolone-specific hybridomas derived from lymph node cells at day 4 after immunization. These early mutations were found mostly in cells with a germinal centre phenotype. No indication of selection at the population level by apoptosis was detected until day 7 after immunization. These results suggest somatic mutations can be induced very early during the immune response in lymph node cells, prior to the peak of clonal expansion and selection with regard to antigen binding.
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| 6. |
- Malmborg Hager, Ann-Christin, et al.
(författare)
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Real time analysis of antibody-antigen reaction kinetics.
- 1992
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 35:6, s. 643-650
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Tidskriftsartikel (refereegranskat)abstract
- Surface plasmon resonance, i.e. detection of changes in refractive index on a surface, was used in a biosensor to evaluate the dissociation/association rate and affinity constants of human monoclonal IgG and IgM antibodies and Tab fragments. The results showed that an observed difference in affinity constants between intact and fragmented IgG anti-tetanus antibody was related to approximately 10-fold differences in dissociation rate constants, since the association rate constants were in the same range, i.e. 2–3×105 (m-1s-1). Affinity constants, as determined by conventional solid phase enzyme immunoassays, were substantially higher than the constants produced by the biosensor. Human monoclonal IgM anti-Tnα antibodies showed, furthermore, one order of magnitude higher association rate constants, as compared with the IgG antibodies, but since the dissociation rate constants were more than ten times higher, the resulting affinity constants of the anti-carbohydrate IgM antibodies were still somewhat lower than those of the IgG antibodies.
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| 7. |
- Huang, Ranyang, et al.
(författare)
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Expression of a Mast Cell Tryptase in the Human Monocytic Cell Lines U-937 and Mono Mac 6
- 1993
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 38:4, s. 359-367
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Tidskriftsartikel (refereegranskat)abstract
- Expression of a mast cell tryptase mRNA was detected in two human monocytic cell lines, the U-937 and the Mono Mac 6, and in normal human peripheral blood(PB) monocytes. In the U-937 cell line but not in normal PB monocytes, the tryptase expression was upregulated 3-50 fold following phorbol ester (PMA)-induced differentiation, but no such induction was seen after retinoic acid, interferon-gamma or vitamin D3 exposure. The tryptases expressed in PMA-induced and non-induced U-937 and in Mono Mac 6 were characterized by PCR amplification and nucleotide sequence analysis. The U-937 cell line was found to express a tryptase identical to one of the previously cloned mast-cell beta tryptases (Tryptase I), and the tryptase expressed in Mono Mac 6 was found to be nearly identical to the previously cloned alpha tryptase. By northern blot analysis with oligonucleotide probes specific for the alpha and beta tryptases both cell lines were found to express only one type of tryptase. Densitometric quantifications of tryptase mRNA levels, in the two cell lines, showed approximately 80 times higher mRNA levels in Mono Mac 6 compared to non-induced U-937. Immunohistochemical staining for tryptase showed a marked heterogeneity in the Mono Mac 6 cell line. Only one out of 10 cells were positive for the protein but the levels in these cells were very high, equivalent, or even higher than the levels seen in the human mast cell line HMC-1. This shows that the expression of a single tryptase, in this case the alpha tryptase, is sufficient for the production of a stable protein and probably also a stable proteolytically active tetramer. The family of human mast-cell tryptases has been considered to represent a class of proteases specifically expressed in mast cells and basophilic leucocytes. The expression of tryptases in two monocytic cell lines and in normal PB monocytes indicate that in humans, the lineage specificity of these serine proteases is less restricted than earlier expected. The cloning of a full length cDNA for the murine counterpart to the human mast cell tryptases, the MMCP-6, is presented. No expression of the MMCP-6 was detected in a panel of mouse monocyte or macrophage cell lines indicating a species difference in the lineage specificity of the 'mast cell tryptases'.
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| 8. |
- Nilsson Ekdahl, Kristina, et al.
(författare)
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Generation of iC3 on the interphase between blood and gas
- 1992
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 35:1, s. 85-91
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Tidskriftsartikel (refereegranskat)abstract
- Earlier studies have shown that C3 can be denatured when blood comes in contact with a polystyrene surface. This study was undertaken to sec if similar denaturation of C3 occurs at the gas plasma interface which is found in all kinds of oxygenator used during cardio-pulmonary operations. An in vitro system consisting of gas bubbling through human blood, serum or plasma was used. The generation of C3a, as an indicator of complement activation, and iC3 and iC3 fragments were monitored. Both C3a and iC3/iC3 fragments levels were increased during bubbling. In contrast to the C3a level, no reduction in iC3/iC3 fragments formation was seen in the presence of EDTA, indicating that il was independent of complement activation. The rate of iC3/iC3 fragments generation was unaffected by the composition of the gas (pure oxygen, pure nitrogen or air), suggesting that the denaturation of C3 indeed occurred at the serum gas interface. C3 and iC3/iC3 fragments were isolated from bubbled EDTA-chelated serum by PEG precipitation and chromatography on FPLC, using a Mono S column and detected by two ELISAs, specific for native C3 and iC3/iC3 fragments. After 240 min approximately 20% of the total amount of C3 consisted of intact iC3 and it was confirmed that this population bound to human erythrocytes.
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| 9. |
- Nilsson, U R, et al.
(författare)
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Modification of the complement binding properties of polystyrene : effects of end-point heparin attachment.
- 1993
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Ingår i: Scandinavian Journal of Immunology. - 0300-9475 .- 1365-3083. ; 37:3, s. 349-354
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, conjugation of heparin to biomaterials has been shown to improve its biocompatibility. The purpose of the present work was to compare complement activation and binding of C3 to unmodified and heparin-treated polystyrene surfaces of microtitre plates. When polystyrene was incubated with human serum, C3 was deposited on the surface by both adsorption and binding dependent on activation of the classical (CPW) and alternative (APW) pathways. After end-point attachment of heparin, significant C3 deposition, although at reduced levels, occurred only by CPW-mediated mechanisms, while adsorption and APW-mediated binding were strongly reduced. Generally, the modified surface bound lower amounts of protein, e.g. serum albumin and IgG, than the unmodified. By contrast, it had increased affinity for C1q which leads to binding of C1 and activation of complement via the CPW. Nevertheless, the net effect of the surface modification on the complement reaction was an overall reduction of C3 binding due to obliteration of APW. This can be related to an enhanced factor H/I-dependent down-regulation of C3b and to the lowered protein-adsorbing property of the surface, both of which have inhibitory effects on APW and on the C3 shunt-dependent activation of the complement system.
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| 10. |
- Rönnelid, J, et al.
(författare)
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Short-term kinetics of the humoral anti-C1q response in SLE using the ELISPOT method : fast decline in production in response to steroids.
- 1994
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Ingår i: Scandinavian Journal of Immunology. - 0300-9475 .- 1365-3083. ; 40:2, s. 243-250
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Tidskriftsartikel (refereegranskat)abstract
- Twenty four systemic lupus erythaematosus patients and 17 patients with other diagnoses were investigated regarding the presence of cells producing C1q reactive antibodies in peripheral blood mononuclear cells using the ELISPOT technique. These results were then compared with parallel serum levels of C1q reactive antibodies. Current production of anti-C1q was almost entirely confined to the systemic lupus erythaematosus group. Longitudinal analysis of anti-C1q ELISPOT positive patients showed rapid changes in the number of anti-C1q producing cells, but only slowly changing serum levels of the corresponding antibodies in response to glucocorticoids. In one systemic lupus erythaematosus patient prednisolone treatment had a selective effect on this autoantibody production, as the production of anti-C1q spot forming cells rapidly dropped to zero, at the same time as the number of total spot-forming cells showed only less change. In another patient, self-limiting connective tissue disease was associated with temporal occurrence of IgM anti-C1q. We believe, from these data, that the ELISPOT method for determination of current antibody production may be of particular value in longitudinal evaluation of disease course and therapeutic effects in systemic lupus erythaematosus and other rheumatic diseases.
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