| 1. |
- Babiker-Mohamed, H, et al.
(author)
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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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In: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 34:5, s. 655-666
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Journal article (peer-reviewed)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.
(author)
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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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In: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 32:1, s. 37-44
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Journal article (peer-reviewed)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. |
- HEDGES, S., et al.
(author)
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Cyclosporin A does not Inhibit IL‐lα‐Induced Epithelial Cell IL‐6 Secretion
- 1993
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In: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 37:5, s. 581-586
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Journal article (peer-reviewed)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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| 4. |
- Malmborg Hager, Ann-Christin, et al.
(author)
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Real time analysis of antibody-antigen reaction kinetics.
- 1992
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In: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 35:6, s. 643-650
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Journal article (peer-reviewed)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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| 5. |
- Nilsson Ekdahl, Kristina, et al.
(author)
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Generation of iC3 on the interphase between blood and gas
- 1992
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In: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 35:1, s. 85-91
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Journal article (peer-reviewed)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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