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Biomedical subjects

E Möller

Publications and source records attributed to E Möller.

At least 55 records · Page 3Linked to original sources
PubMed1995

Differential sensitivity to transforming growth factor (TGF)-beta of CBA and of CBA/N B cells demonstrates that the IgG2b inducing factor in synovial fluid from rheumatoid arthritis patients is not identical to TGF-beta.

Synovial fluid from patients with rheumatoid arthritis (RA-SF) contains in vivo produced cytokines and inflammatory mediators, including a factor that induces IgG2b production of lipopolysaccharide (LPS) preactivated murine B lymphocytes. In order to determine the mechanism by which RA-SF acts on LPS activated mouse B cells, CBA/N mice were used as an experimental model. The X-linked immunodeficiency of these mice is caused by a point mutation in the Bruton's tyrosine kinase (btk) gene. We have earlier shown that RA-SF can reconstitute the CBA/N B cell deficiency in vitro and in vivo, with regard to IgG2b production after LPS stimulation. Since transforming growth factor (TGF)-beta has been suggested to be a switch factor for IgG2b, we aimed at investigating the role of TGF-beta in our experimental system. We found that TGF-beta could not mimic the effect of RA-SF on CBA spleen cells. A small increase of IgG2b secretion was observed with spleen cells from normal CBA mice, whereas Ig secretion of all isotypes was suppressed in CBA/N spleen cells treated with TGF-beta at any concentration. Neutralizing antibodies against TGF-beta suppressed the response of CBA B cells, whereas the response by CBA/N B cells was enhanced by the same antibody preparation. Here we also show that the abnormal B cell responsiveness to TGF-beta, typical of CBA/N, co-segregates with the btk mutation in male (CBA x CBA/N)F2 spleen cells. This was determined by allele specific PCR recognizing the identified base substitutions of the btk gene, typical of the two strains. We propose that RA-SF contains a factor, separate from TGF-beta, that is involved in the differentiation of IgG2b expressing cells.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1995

Human IgG rheumatoid factors and RF-like immune complexes induce IgG1 rheumatoid factor production in mice.

The synovial fluid of patients with rheumatoid arthritis (RA) was found to contain IgG and/or IgG-containing immune complexes (ICs) that stimulated an intense antibody formation when injected into mice of certain strains, notably of NZ background. The response was characterized by high and sustained levels of IgG1 antibodies with rheumatoid factor (RF) activity. In the study described, we investigated whether it is the antibodies with RF activity in the synovial fluid, that are responsible for stimulation of mouse RF in vivo. Different mouse strains were injected with synovial fluid from a seropositive RA patient (RA-SF), with human monoclonal antibodies with RF activity, with a human non-RF monoclonal antibody or with different preformed RF-like antibody-antibody (Ab-Ab) ICs. The experimental mice were monitored subsequently for IgG1 RF production. IgG1 RF antibodies were found in all strains (NZB, BALB/c and CBA) injected with Ab-Ab ICs formed at equivalence, but only in NZB using RA-SF or human monoclonal antibodies with RF activity. Optimal production of IgG1 RF by Ab-Ab ICs required the integrity of Fc and F(ab)'2 portions respectively of the antibodies; soluble and truncated ICs were less effective. Further studies demonstrated that the IgG1 RF response was not simply the result of a specific immune response against human IgG, since humoral immunity against human IgG was induced only when combined with an efficient adjuvant. During a typical adjuvant-associated primary response specific antibodies of IgM, IgG1 and IgG2a isotypes were found, i.e. quite different from the selective IgG1 response induced by RF-like containing immune complexes. This conclusion is substantiated further by the clear differences in responses to IgG containing fraction obtained from RA-SF in NZ mice compared to other strains. Our findings argue for a different type of reaction leading to the selective IgG1 response and might aid in elucidating the mechanisms for chronic production of antibodies with RF activity in patients with RA.

Animals↗
PubMed1995

Cell interactions and cytokines in transplantation immunity.

Peripheral T cells usually harbor clones that can directly recognize allogeneic HLA molecules in association with hitherto undefined allogeneic peptides. However, recognition does not lead to activation of allograft immunity, unless the allogeneic cells are professional ISCs. In the absence of such cells in the graft, activation of specific alloimmunity might occur indirectly by host ISCs presenting graft-derived allogeneic peptides. Such peptides are thought to often be derived from allogeneic HLA molecules themselves. A local inflammation followed by activation of endothelial cells could facilitate the migration of immunocompetent cells into the graft parenchyma and stimulation by dendritic cells in the graft. A local inflammation is believed to be induced by ischemic damage to cells in the graft, to postoperative aseptic inflammation associated with wound healing and repair, or by ongoing local infection. Naive or virgin T cells primarily migrate to secondary lymphoid organs and specific subsets of T cells traffic selective organs such as the gut or lymph nodes. However, memory T cells extravasate to sites of local inflammation. Therefore, prior T-cell alloimmunity, which might be the result of immunity against cross-reactive self-HLA restricted foreign peptides, as well as a local inflammatory reaction in the graft, caused by tissue damage or mediated by preexisting low levels of noncytotoxic antibodies, might facilitate graft rejection.

Animals↗
PubMed1994

Transplantation of porcine fetal pancreas to diabetic patients.

Transplantation of fetal porcine islet-like cell clusters (ICC) reverses diabetes in experimental animals. We have now transplanted porcine ICC to ten insulin-dependent diabetic kidney-transplant patients. All patients received standard immunosuppression and, at ICC transplantation, antithymocyte globulin or 15-deoxyspergualin. ICC were injected intraportally or placed under the kidney capsule of the renal graft. Four patients excreted small amounts of porcine C-peptide in urine for 200-400 days. In one renal-graft biopsy specimen, morphologically intact epithelial cells stained positively for insulin and glucagon in the subcapsular space. We conclude that porcine pancreatic endocrine tissue can survive in the human body.

Adult↗
PubMed1994

Specific inhibition of HLA class I and II antibodies by soluble antigens--a method for the identification of antibody specificity in sera from alloimmunized individuals.

HLA class I and II antigens were purified to be used for the determination of the specificity of lymphocyte reactive antibodies in renal transplant patients. Purification of HLA antigens was achieved by affinity chromatography using rabbit antibodies directed to human beta 2 microglobulin, W6/32 antibodies that recognize a nonpolymorphic determinant on HLA class I molecules, and BU25 monoclonal antibodies directed to a monomorphic determinant on HLA class II molecules. Pooled platelets and spleen lymphocytes from a large number of donors were used as a source of class I and II antigens. HLA antigen preparations, highly enriched as shown in Western blot experiments, were obtained that caused a dose-dependent inhibition of the binding as well as of the cytotoxicity of W6/32 and BU25 antibodies. The HLA class I preparation did not inhibit the binding of monoclonal antibodies to T or B cell-specific surface markers or to HLA class II antigens. Similar kinds of results were obtained with the HLA class II antigen preparation, which only specifically blocked the class II antibody binding. The antigen preparations were tested for their ability to block binding of antibodies in sera from alloimmunized patients. In order to avoid complications by soluble HLA antigens, all sera were absorbed in ELISA plates coated with anti-class I and anti-class II monoclonal antibodies. The HLA class I and class II antigen preparations were found to be HLA-specific. All data were compared with the conventional method to determine HLA specificity--i.e., specific blocking of class I and class II reactivity using monoclonal antibodies and unabsorbed sera. Soluble HLA antigens, added directly to mixtures of patient sera and lymphocytes used in the cytotoxicity or binding tests, can therefore be used for determination of the presence of HLA antibodies in sera of alloimmunized patients.

Antibodies, Monoclonal↗
PubMed1994

Protein-G binding material from synovial fluid of rheumatoid arthritis patients induces unorthodox autoantibodies (IgG1 rheumatoid factor) in NZB, NZW and (NZB x NZW)F1 mice.

Our previous studies have demonstrated that injection of rheumatoid arthritis (RA) synovial fluid (SF) induces a marked increase mainly of IgG1 antibody-producing cells in autoimmune disease prone (NZB x NZW)F1 mice but not in CBA mice. In the present study, the in vivo effect of RA-SF on autoantibody production was tested in different strains of mice. Injection of RA-SF induced the production of unorthodox autoantibodies (IgG1 rheumatoid factor, RF) in young (NZB x NZW)F1 mice as well as in their parental strains NZB and NZW, but not in normal mice (CBA) or in mice with severe combined immunodeficiency, indicating that the response is not caused by a conventional immune response against RA-SF material. IgG1 RF production was rapidly induced and reached high levels already on day 7 and lasted for more than 90 days. The induction of IgG1 RF was not the result of polyclonal activation, since RA-SF did not stimulate the production of other antibodies, such as autoantibodies against double-stranded DNA, bromelain-treated mouse red blood cells, myosin, transferrin, cytochrome c, thyroglobulin or myoglobin or antibodies reactive with the hapten TNP. To elucidate the identity of the active substance in RA-SF, responsible for IgG1 RF production, bound and unbound material of RA-SF, eluted from a protein-G column was injected into (NZB x NZW)F1 mice. Only the protein-G binding material was active, indicating that the effect is mediated by autoantibodies or immune complexes in the synovial fluid. Further studies demonstrated that identical concentrations of protein obtained from a pool of normal human IgG or SF from seronegative RA and non-RA arthritides patients did not contain the same activity.

Animals↗
PubMed1994

Xenorecognition and xenoimmunity.

Human T lymphocytes can respond against pig stimulator cells according to a direct pathway of activation, indicating that no major differences exist between human T cell mediated alloresponses and xenospecific responses against pig stimulator cells in vitro. However, even if pig PBMC can activate T cells directly, it is believed that porcine islet cell clusters are incapable of activating cellular immunity directly in vivo, since ICC xenotransplants are thought to lack antigen-presenting cells. Therefore, specifically immunized T lymphocytes are not likely to be able to interact directly with xenogeneic target cells. We propose that xenogeneic transplants lacking antigen-presenting cells are subjected to antibody-dependent cell-mediated rejection mechanisms. The humoral xenoimmune response against pig antigens was swift and strong in all transplanted patients with peak antibody reactivities recorded on days 30-40. Titer increases in all lg-classes and subclasses were found. The humoral immune response was mainly, if not exclusively, directed against alpha-linked galactose-containing sugar residues, present on many different glycoproteins, including SLA class I antigens. There were no signs of de novo stimulation of B cell clones following xenoimmunization, rather an increased reactivity in cells producing xenospecific antibodies as part of the normal background of antibody production in healthy individuals. The findings form part of a basis for understanding xenoimmune mechanisms in man. The relatively homogeneous antibody specificities found both in normal and in immune patients are promising for future xenotransplantation using pig organs in man.

Animals↗
PubMed1993

Similar frequencies and kinetics of cytokine producing cells in murine peripheral blood and spleen. Cytokine detection by immunoassay and intracellular immunostaining.

Production of IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, IFN-gamma, GM-CSF (granulocyte-macrophage colony stimulating factor) and macrophage colony stimulating factor by murine peripheral blood and spleen cells was analyzed following primary and secondary mitogen stimulation in vitro. Individual cytokine producing cells were detected by an intracytoplasmic staining technique. Cytokine production in cells from peripheral blood and spleen was comparable and more rapidly induced by calcium ionophore and phorbol 12-myristate 13-acetate than by concanavaling A. Restimulation in vitro induced both a swift production of cytokines and, for some cytokines, higher frequencies of producing cells. This was especially evident for IL-10 secreting cells, which increased 30-80 times in secondary responses. These analyses using the dual approaches of immunoenzymetric and fluorescent immunohistochemical techniques provide important evidence that cytokine induction kinetics can differ following primary or secondary stimulation.

Animals↗
PubMed1993

Selective presence of IgG2b inducing factor in synovial fluid of patients with rheumatoid arthritis.

The factor, that we have defined and called IgG2b inducing factor, in synovial fluid of rheumatoid arthritis patients (RA-SF) has previously been well characterized both in vitro and in vivo revealing that RA-SF induces a significantly higher IgG2b antibody production in LPS activated murine spleen cells. This activity was separated from the hitherto identified cytokines or factors in RA-SF. In this study we have compared the IgG2b inducing activity in RA-SF with synovial fluid from patients with non-RA arthritides. Here we show that the IgG2b inducing activity is significantly enriched in patients with RA compared to patients with non-RA arthritides and it is not found in healthy, post-traumatic, control groups. We do not yet know the implications of this finding for the disease progress of rheumatoid arthritis, but we believe that the identification of this B cell differentiation factor might elucidate the mechanism leading to hyperactivation of B cells in rheumatoid arthritis.

Animals↗