Biomedical subjects

C J Elson

Publications and source records attributed to C J Elson.

At least 91 records · Page 5Linked to original sources

PubMed1992

Dependency on interleukin-1 of primary human in vitro T cell responses to soluble antigens.

The role of interleukin (IL)-1 in antigen-specific activation of naive human T cells has been examined. Primary human T cell proliferative responses to the soluble antigen keyhole limpet hemocyanin (KLH) were decreased by neutralizing antisera to IL-1 alpha (25 +/- 7% standard error) and IL-1 beta (56 +/- 6% standard error). Inhibition by both antisera in a primary culture was usually additive. Recombinant IL-1 alpha and recombinant IL-1 beta could both re-establish responses in cultures blocked by neutralizing anti-IL-1 beta. Interestingly, the susceptibility of KLH-stimulated T cell responses to inhibition by neutralizing anti-IL-1 sera decreased with time in culture. This observation suggested that T cell responses may become less IL-1 dependent as T cells become activated or primed. In support of this notion, secondary T cell responses to purified protein derivative from Mycobacterium tuberculosis (PPD) were markedly less affected by the addition of comparable amounts of the neutralizing anti-IL-1 sera. These results demonstrate that IL-1 is one of the main co-stimulators for primary T cell activation and suggest a different requirement for IL-1 in the activation of naive compared to memory human T cells.

Cells, Cultured↗

PubMed1992

Autoimmune haemolysis in the dog: relationship between anaemia and the levels of red blood cell bound immunoglobulins and complement measured by an enzyme-linked antiglobulin test.

A direct enzyme-linked antiglobulin test (DELAT) was used to measure the levels of red blood cell (RBC) bound IgG, IgM, IgA and C3 in dogs with autoimmune haemolytic anaemia (AIHA). At presentation, one or more DELAT parameters was raised in each AIHA case, and the RBC were typically coated with immunoglobulin of more than one class, together with C3. There was no relationship between the levels of RBC-bound IgG, IgM or IgA and the severity of the anaemia, although a significant negative correlation (rs = -0.66, P < 0.02) was found between bound C3 and blood haemoglobin concentration. These results indicate that the level of sensitisation of erythrocytes with IgG alone is not a reliable predictor of the severity of haemolysis in different cases, and that the pathogenesis of AIHA can be complex, involving multiple immunoglobulin classes and complement in the destruction of RBC. A significant relationship (rs = 0.63, P < 0.02) was found between serum IgG concentration and haemoglobin levels, and it is suggested that this may be due to free IgG inhibiting the interaction of IgG-sensitised RBC with macrophages. Serial measurements from individual AIHA cases during treatment revealed that the levels of RBC-bound immunoglobulins fell simultaneously with improvements in anaemia. In one dog, a relapse was associated with increases in bound IgG and IgM. Transient relative reticulocytopenia at presentation was common, but was not related to the severity of the anaemia. However, in other cases there was a persistent failure to increase RBC production, which was associated with slower recovery.

Anemia, Hemolytic, Autoimmune↗

PubMed1992

IL-1 secreting cell assay and its application to cells from patients with rheumatoid arthritis.

The cells within a population that were secreting interleukin-1 (IL-1) were enumerated and visualized by an ELISA-SPOT assay. Initial experiments designed to validate the assay revealed that the number of IL-1 beta spot forming cells was increased by exposing normal blood monocytes to LPS and that spot formation was prevented by incubating the cells with cycloheximide. Normal blood polymorphonuclear leucocytes (PMNs) produced IL-1 alpha and IL-1 beta in response to recombinant granulocyte monocyte colony stimulating factor (rhGMCSF) but not to cytochalasin B, calcium ionophore or LPS. Monocytes and PMN were isolated from the synovial fluid (SF) and blood of patients with rheumatoid arthritis (RA) and the ability of these cells to secrete IL-1 alpha and IL-1 beta compared. A higher proportion of SF derived monocytes were found to secrete IL-1 beta spontaneously compared to the corresponding blood cells. IL-1 alpha secreting monocytes were not detected although high numbers of IL-1 alpha secreting cells were found among cells isolated from rheumatoid synovium. By contrast SF PMNs did not produce IL-1 alpha or IL-1 beta whereas blood PMNs from some (3/8) RA patients produced IL-1 alpha and/or IL-1 beta. It is considered that the IL-1 ELISA-SPOT is a highly sensitive technique for detecting IL-1 secreting cells.

Aged↗

PubMed1992

Susceptibility of normal and arthritic human articular cartilage to degradative stimuli.

Recombinant interleukin-1 (IL-1) alpha and beta stimulated significant loss of glycosaminoglcan (GAG) content from normal (non-arthritic) articular cartilage explants but only after incubation for 14 days and only in specimens from 8/21 (38%) individuals. By contrast, all cartilage specimens but one from patients with osteoarthritis (OA) and rheumatoid arthritis (RA) were degraded (as judged by their reduced GAG content) by the recombinant cytokines but again only after 14 days' incubation. The reduction in GAG induced by IL-1 was also greater for both OA and RA cartilage than normal cartilage. Synovial fluids (SFs) from RA patients stimulated greater loss of GAG content from OA cartilage explants than normal explants although in both cases the loss was evident within 2 days. It is concluded that cartilage explants from some individuals are susceptible to the degradative effects of IL-1 whereas others are refractory and that arthritic cartilage is more susceptible to degradation by both IL-1 and RA SFs than non-arthritic cartilage.

Aged↗

PubMed1992

Kinins--key mediators in inflammatory arthritis?

Recent evidence suggests an important role for kinins in the generation of pain, swelling and the cellular damage associated with inflammatory joint disease. Kinins are considered to be pro-inflammatory peptides for a variety of reasons. They stimulate c fibres in the synovium to cause pain and increase extravasation of fluid to produce swelling. Kinins possess the capacity to release neurotransmitters (substance P, acetylcholine) and a second wave of mediators (interleukin-1, tumour necrosis factor, interleukin-8, prostaglandins, leukotrienes). The steady levels and turnover of kinins is regulated by formation (enzymic action of kininogenases on endogenous substrates called kininogens) and by metabolism (kininases, peptidases that hydrolyse kinins). These components of the kinin system can enter the synovial joint space either by transudation from the plasma or from degranulating neutrophils chemotactically attracted into the synovium from which they migrate into the synovial fluid. If kinins are involved, one would expect neutrophil derived mediators of the system to dominate in rheumatoid arthritis and psoriatic arthritis and plasma derived products to be more important in osteoarthritis and gout. But, the question whether any of the functions attributed to each component of the system can be considered to be a primary factor in the cellular pathology of inflamed joints remains to be established. Future investigations, including therapeutic trials with kinin antagonists and kallikrein inhibitors, will need to address the differential role of the kallikreins and kinins in the different types of synovitis, on symptoms of inflammation and on any remedial effects on the progression of tissue damage within the joint.

Amino Acid Sequence↗

PubMed1992

Identification of autoantigens in autoimmune haemolytic anaemia by a non-radioisotope immunoprecipitation method.

In human autoimmune anaemia (AIHA), warm autoantibodies frequently appear to have serological specificity for the Rh complex, but to date, immunochemical techniques have failed to demonstrate that the antibodies react with Rh-associated polypeptides. We describe the immunoprecipitation of red blood cell (RBC) autoantigens, using biotin labelling and a luminescent detection method. In three cases of warm AIHA, a band of 32 kD and a diffuse zone of 38-51 kD or 40-51 kD were specifically precipitated by eluted RBC autoantibody. This pattern corresponds closely with that precipitated by two Rh-specific monoclonal antibodies, BRIC 207 and AB5. Antibody from the three eluates also showed serological specificity for the Rh complex in a haemagglutination assay against a panel of RBC with a range of Rh phenotypes, including rare -D-/-D- and Rh null cells. Eluted autoantibody from another warm AIHA patient immunoprecipitated a peptide of 67 kD that did not correspond in apparent molecular mass either with Rh-associated bands, or with major RBC membrane proteins or sialoglycoproteins (SGP). The haemagglutination assay showed that this eluate contained both Rh-specific and Rh-unrelated antibody. Warm autoantibody eluted from the RBC of a clinically normal, but direct antiglobulin test positive, blood donor was serologically unreactive with the Rh complex, and immunoprecipitated unknown peptides of 26, 29, 35, 48 and 51 kD, together with a band of 90 kD that comigrated with SGP alpha 2 (glycophorin A). In six further warm AIHA cases, no antigens were precipitated by autoantibody-containing RBC eluates. Overall, the results demonstrate that autoantibodies bind to Rh polypeptides in some, but not all, patients with warm AIHA, suggesting that the aetiology of the disease may vary.

Adult↗

PubMed1992

Red cell autoantibody production by colonic mononuclear cells from a patient with ulcerative colitis and autoimmune haemolytic anaemia.

We have studied the ability of mononuclear cells extracted from the colon (CMC), draining lymph nodes (LNMC), peripheral blood (PBMC) and spleen (SMC) of a patient with ulcerative colitis and severe autoimmune haemolytic anemia to produce red cell autoantibodies. The LNMC, PBMC and SMC secreted immunoglobulin in vitro in pokeweed mitogen culture but not spontaneously. They also produced immunoglobulin when transferred to severe combined immunodeficient (SCID) mice but no anti-red cell activity was demonstrable. In contrast, in vitro cultures of CMC produced immunoglobulin spontaneously, showing the presence of activated B-cells and plasma cells, but anti-red cell activity could not be demonstrated. However, CMC transferred to SCID mice were able to produce IgG with anti-red cell activity. These results concur with clinical observations suggesting that the colon is the source of red cell autoantibodies in these patients.

Adult↗

PubMed1992

Agalactosyl IgG in pristane-induced arthritis. Pregnancy affects the incidence and severity of arthritis and the glycosylation status of IgG.

The effect of pregnancy on the incidence and severity of pristane-induced arthritis was examined along with the glycosylation status of IgG during the ante-natal and post-partum periods. It was found that pristane-induced arthritis is prevented by pregnancy. In addition, the levels of agalactosyl IgG fall during pregnancy but rise to greater than normal within a few days of parturition, before resetting towards the norm shortly afterwards. Interestingly, the level of agalactosyl IgG correlates with the severity of arthritis. As previously reported IL-6 may be an important factor, not necessarily the only one, in the production of agalactosyl IgG. Here it is clearly demonstrated that the kinetics of IL-6 activity post-pristane injection parallels the kinetics of agalactosyl IgG production. In addition, the overshoot in agalactosyl IgG levels immediately post-partum coincides with a burst in IL-6 activity. It is considered that these changes in IgG glycoform levels, or the factors which control them, may be related to the mechanisms underlying prevention/remission of arthritis during pregnancy.

Animals↗

PubMed1992

Relationship between interleukin 6, agalactosyl IgG and pristane-induced arthritis.

IL-6 titres in sera and peritoneal exudate fluids (PEF) derived from pristane injected DBA/1 and CBA/Igb mice were measured. Arthritic DBA/1 mice had significantly higher serum IL-6 titres than nonarthritic or normal mice at 160 days post pristane injection. By contrast, although both arthritic and non-arthritic CBA/Igb mice had higher serum IL-6 titres than normal mice, there was no significant difference in serum IL-6 titre between these two groups at day 200-230. In both strains of mice, the IL-6 titres in PEF were more than 10 times serum levels regardless of arthritis. As previously reported for CBA/Igb mice, agalactosyl IgG levels are raised in pristane injected DBA/1 mice and the percentage is higher in arthritic animals than that in non-arthritic mice. An association between serum agalactosyl IgG levels and PEF IL-6 in pristane injected DBA/1 was demonstrated. Moreover, the injection of recombinant IL-6 into normal mice increased their serum agalactosyl IgG levels. However, it is considered that IL-6 is not the only factor involved in the production of agalactosyl IgG.

Animals↗

PubMed1992

Failure of blood mononuclear cells from human donors with autoimmune haemolytic anaemia to reconstitute severe combined immunodeficient mice.

The use of severe combined immunodeficient (SCID) mice to study humoral responses by peripheral blood mononuclear cells (PBMC) from patients with autoimmune haemolytic anaemia (AIHA) was assessed. Upon transfer to SCID mice, PBMC from normal donors and patients with autoimmune thyroid disease (AITD) produced substantial levels of immunoglobulin (Ig), detectable in the plasma of recipient SCID mice. In contrast, the majority of PBMC from AIHA donors did not produce Ig in recipient mice. The capacity of PBMC to reconstitute SCID mice was not related to the donor's age. In one case, remission of AIHA allowed the donor's PBMC to successfully reconstitute SCID mice, despite the fact that the donor had developed immune thrombocytopenic purpura (ITP). AIHA PBMC were viable by dye exclusion and contained cells in various states of activation, as judged by their IgG secretion profiles when cultured in vitro. The proportions of leukocytes in AIHA PBMC (T to B cell ratios, CD4+ to CD8+ cell ratios and monocytes) were highly variable compared to non-AIHA PBMC. To determine the effect of abnormal lymphocyte proportions on SCID reconstitution, depletion experiments were carried out on normal and AITD PBMC. This work demonstrated a requirement for high T cell numbers, especially CD4+ cells, and minimal B cell numbers for successful reconstitution. CD8+ depletion of PBMC led to increased levels of Ig production in some instances. It is considered that PBMC from AIHA patients have a defect different from that of other autoimmune disorders, which renders them incapable of reconstituting SCID mice.

Adolescent↗

PubMed1992

Mediators of joint swelling and damage in rheumatoid arthritis and pristane induced arthritis.

Joint swelling and tenderness in rheumatoid arthritis (RA) probably result from IgG aggregates activating complement with the consequent attraction of polymorphonuclear leucocytes (PMNs) and the liberation of their granule enzymes such as kininogenases. By contrast IL-1 and TNF are the major stimulants of cartilage and bone loss although other agents contribute. The fundamental drive for the production of these mediators is unknown but a role for heat shock proteins is suggested from work on pristane induced arthritis.

Animals↗

PubMed1992

Differential effects of immunisation with mycobacterial 65 kD heat shock protein on two models of autoimmunity.

The effects of preimmunisation with the 65 kD mycobacterial heat shock protein (hsp65) on 2 murine models of autoimmunity were compared. Experimental autoimmune haemolytic anaemia (AIHA) can be provoked in mice by repeated injection with rat red blood cells (RBC). In this model, preimmunisation with hsp65 10 days before induction of disease resulted in a partial, but significant, reduction in RBC-bound autoantibody levels measured by Coombs' test. However, preimmunisation with human IgG (hIgG) was associated with a similar suppressive effect. Administration of neither hsp65 nor hIgG affected the direct or indirect anti-rat agglutinin titres of mice subsequently injected with rat RBC. Injection of hsp65 or hIgG prior to induction of AIHA elicited the production of IgG antibodies against the respective immunogen, as judged by enzyme-linked immunosorbent assays. In contrast to the results in experimental AIHA, pristane-induced arthritis (PIA) was effectively prevented by preimmunisation with hsp65, but not with hIgG. It is considered that, whilst hsp65 injection may slightly reduce subsequent anti-RBC autoantibody production in AIHA by antigenic competition, such a mechanism cannot account for the substantial protection against PIA afforded by hsp65 preimmunisation. We suggest that the high, sustained production of anti-hsp65 antibodies observed in mice given hsp65 and pristane may play a role in specifically suppressing arthritogenic immune responses in PIA.

Anemia, Hemolytic, Autoimmune↗

PubMed1992

Determination of tissue kallikrein and alpha 1-antitrypsin-tissue kallikrein complexes in synovial fluid of patients with rheumatoid, osteo and psoriatic arthritis.

An enzyme-linked immunosorbant assay was developed to determine tissue kallikrein and alpha 1-antitrypsin-tissue kallikrein complexes in pooled synovial fluid of patients with rheumatoid, osteo and psoriatic arthritis. Even though basal values could be determined, the addition of synovial fluid shifted the standard curves for both tissue kallikrein and alpha 1-antitrypsin-tissue kallikrein complex to the right, because of the presence of a novel inhibitor.

Arthritis, Psoriatic↗

PubMed1992

Antibody responses to the blood group antigen D in SCID mice reconstituted with human blood mononuclear cells.

Mice with severe combined immunodeficiency (SCID) were reconstituted with peripheral blood mononuclear cells (PBMC) obtained from D-negative individuals who had been sensitized to D-positive erythrocytes. Anti-D was spontaneously secreted in mice reconstituted with PBMC obtained from donors within 14 days of re-immunization with D-positive erythrocytes, but was not detected in murine plasma when mice were reconstituted with PBMC obtained from the same donors many years after sensitization, even though anti-D was still present in the serum of these donors. In the murine plasma the anti-D titres were not related to the total human immunoglobulin concentrations. SCID mice reconstituted with PBMC from some donors immune to D-positive erythrocytes (but not immunized within 34 days of donating the sample) made a recall response to the D antigen, which in some cases was maintained for at least 84 days. Depletion of adherent cells from the reconstituting PBMC reduced the total concentration of human IgG obtained. These results show that SCID mice reconstituted with human PBMC (Hu PBMC-SCID) can make a recall response to the D antigen which cannot be attributed to non-specific polyclonal B-lymphocyte activation, and that efficient antigen processing and presentation of the integral erythrocyte membrane D polypeptide occurs in the Hu PBMC-SCID model.

Animals↗

PubMed1991

Human cartilage is degraded by rheumatoid arthritis synovial fluid but not by recombinant cytokines in vitro.

Rheumatoid arthritis (RA) synovial fluid (SF) stimulated significant loss of glycosaminoglycans (GAG) from normal and pathological human cartilage biopsies over 2 days as compared with normal human serum. By contrast, 15 RA SFs failed to degrade killed normal cartilage, and degraded killed RA cartilage less effectively than living RA cartilage. Four RA SFs were treated with neutralizing anti-cytokine antisera prior to incubation with normal cartilage. The degrading effects of two of the fluids were reversed by anti-interleukin-1 alpha (IL-1 alpha) while degradation by the third and fourth fluids were reversed by anti-interleukin-1 beta (IL-1 beta) and anti-tumour necrosis factor-alpha (TNF-alpha), respectively. However, recombinant human IL-1 alpha, IL-1 beta, TNF alpha or a combination of all three cytokines had no degrading effect in this 2-day culture system. It is concluded that RA SF degrades cartilage by a mechanism involving a synergistic interaction between cytokines and some other component of SF.

Arthritis, Rheumatoid↗

PubMed1991

Identification of autoantigens in canine autoimmune haemolytic anaemia.

Autoantigens in canine autoimmune haemolytic anaemia (AIHA) were identified by immunoprecipitation using autoantibody eluted from the erythrocytes of affected dogs. At least three patterns of precipitated antigen were identified in six cases of AIHA. The most commonly precipitated antigen pattern was a combination of 42-kD and 29-kD peptides, associated with up to three other membrane components. These autoantigens may be canine glycophorins, which are of similar molecular mass, or may possibly represent an equivalent of the human Rhesus complex. An autoantigen identical in molecular mass to band 3, the erythrocyte anion channel protein, was precipitated in one case of AIHA, and unknown peptides of 37 kD and 100 kD were isolated by autoantibody from another dog. In one case, no antigens were precipitated by the eluted antibody, indicating that the autoantibody may have bound a non-protein membrane component such as phospholipid. Overall it is considered that the different patterns observed may reflect differences in the aetiology of the condition. In other studies, sera from dogs with AIHA failed to immunoprecipitate autoantigens, but were shown by immunoblotting to contain autoantibodies to proteins of the erythrocyte cytoskeleton. Such autoantibodies were also demonstrated in normal canine sera and it is suggested that they are unlikely to play a role in the pathogenesis of AIHA, but may be part of a normal clearance mechanism for damaged red blood cells.

Anemia, Hemolytic, Autoimmune↗

PubMed1991

Identification of a myeloperoxidase inhibitor from normal human serum.

An inhibitor of myeloperoxidase (MPO) has been identified in normal human serum. Initial experiments confirmed that high levels of MPO inhibitory activity are present in sera and that the inhibitor did not act by interfering with the assay. Purification of the inhibitor activity by salt precipitation followed by ion exchange and affinity chromatography revealed the presence of a protein of 150 kD. The purified inhibitory activity displayed dose and time dependency and was not associated with IgG or IgA. It is considered that human serum contains an inhibitor of extracellular MPO capable of protecting against hypohalous acid release in host tissues and that if inhibitor levels are reduced such protection may fail.

Arthritis, Rheumatoid↗

PubMed1991

Differential responses of human and rat cartilage to degrading stimuli in-vitro.

Human cartilage biopsies incubated for 2 days in-vitro with 15% synovial fluid from rheumatoid arthritis patients contained less glycosaminoglycans (GAG) than control biopsies. Recombinant human (rHu)-interleukin-1 alpha (IL-1 alpha) and IL-1 beta at 10 or 100 ng mL-1 had no effect on human cartilage GAG levels. Similarly, GAG loss from human cartilage biopsies into medium over 5 days was significantly increased by synovial fluid but unaffected by 100 ng mL-1 IL-1 alpha or IL-1 beta compared with controls. However, when rat femoral head cartilage samples were incubated with 100 ng mL-1 rHu-IL-1 alpha or IL-1 beta for 5 days there was a significant increase in GAG loss from the cartilage into medium, whilst human synovial fluid significantly decreased the loss of GAG from rat cartilage into medium, compared with controls. The results demonstrate that human and rat cartilage differ from each other in their responses to degrading stimuli and suggest that animal cartilage may have limited application for the screening of drugs intended for the treatment of human arthritides.

Animals↗