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Biomedical subjects

D G Williams

Publications and source records attributed to D G Williams.

At least 55 records · Page 3Linked to original sources
PubMed1994

Mycobacteria precipitate an SLE-like syndrome in diabetes-prone NOD mice.

Non-obese diabetic (NOD) mice spontaneously develop organ-specific autoimmunity and are widely used as a model for diabetes. Aged NOD mice also exhibit some features of non-organ-specific autoimmune rheumatic disease such as anti-nuclear antibodies and late-onset haemolytic anaemia. Here, we report that a single dose of 2.6 x 10(7) heat-killed bacillus Calmette-Guérin (BCG) i.v. in 8-week-old NOD mice prevented diabetes but precipitated a syndrome similar to systemic lupus erythematosus (SLE). Treated mice developed haemolytic anaemia, anti-DNA and anti-Sm anti-nuclear autoantibodies and an increased severity of sialadenitis. Perivascular lymphocytic infiltration in the kidneys and glomerular immune complex deposition were also found. The action of BCG appeared to be mediated by an adjuvant-like activity as treated mice showed a substantial increase in reticuloendothelial cell function and enhanced antigen presentation capacity.

Anemia, Hemolytic, Autoimmune↗
PubMed1993

The snRNP core protein SmB and tissue-specific SmN protein are differentially distributed between snRNP particles.

The SmN protein is a tissue specific component of the small nuclear ribonucleoprotein particle which is closely related to the ubiquitously expressed SmB protein but is expressed only in the brain and heart. To investigate the function of SmN, its localisation within different snRNP particles was investigated using a range of anti-snRNP monoclonal antibodies. SmN and SmB were found to exhibit different patterns of association with snRNP particles in two cell lines, ND7 and F9 which express SmN. In both cases, SmN was found to be present in the U-2 snRNP but was excluded from the U-1 snRNPs whereas SmB was present in both U-1 and U-2 snRNPs. Data from transfected 3T3 mouse fibroblasts cell lines artificially expressing a low level of SmN also confirm this observation. In contrast, SmN was found to be an integral component of both the U-1 and U-2 snRNPs in both 3T3 cells artificially expressing high levels of SmN and in adult rat brain which has a naturally high level of SmN expression. Taken together, the results suggest that the pre-U1 snRNP particle has a lower affinity for SmN than for SmB. Thus, SmN expressed at low levels incorporates into U2, but SmN expressed at high levels incorporates into both U1 and U2 snRNPs and replaces SmB. The significance of these effects is discussed in terms of the potential role played by SmN in constitutive and alternative splicing pathways in neuronal cells.

3T3 Cells↗
PubMed1993

Pathogenesis of idiopathic IgA nephropathy.

Despite a prodigious amount of work on the physiology of IgA production in man, and many studies on the immunopathology of IgA nephropathy, ranging from the immunogenetics to the immune response to chemical characteristics of the IgA, we are hardly any nearer to defining the pathogenesis of this disease. One of the main changes in our understanding has been to recognise that the bone marrow, now known to produce normally one-third of the body's IgA, overproduces this immunoglobulin in IgA nephropathy. This alters the previous notion that IgA nephropathy was due simply to IgA production in the mucosa, although a mucosal component is not excluded. Certain characteristics of the IgA in the diseased kidney and the circulation have been defined: it is of subclass IgA1 and has a higher proportion of lambda light chains and negative charge than in normal subjects. The specificities of the IgA, either in the kidney or in complexes, have not helped to clarify the pathogenesis. They have been found for a wide range of endogenous and exogenous antigens, suggesting that the antibody activity represents polyclonal B cell activation. These findings have not helped to confirm the prevailing theory that IgA nephropathy is an immune complex disease. Other theories put forward are that IgA nephropathy is an autoimmune disease, glomerular components or IgA itself being among the candidate antigens, or that there is primary dysregulation of the IgA immune system. At this stage of development in our understanding of this common nephropathy, it is important to guard against the assumption that idiopathic IgA nephropathy is one disease and is the result of a single pathogenetic mechanism.

Glomerulonephritis, IGA↗
PubMed1993

Lupus autoantibodies discriminate between the highly homologous Sm polypeptides B/B' and SmN by binding an epitope restricted to B/B'.

The ubiquitous Sm polypeptides B/B' (28 and 29 kD) and the highly homologous tissue-specific Sm N polypeptide (29 kD) share several autoepitopes recognized by systemic lupus erythematosus (SLE) sera. Previous studies on the antigenicity of nuclear antigens recognized by human autoantibodies have not discriminated between ubiquitous and tissue-specific forms. We set out to examine whether a tissue-specific nuclear antigen, Sm N, is autoantigenic in SLE by comparing the immunoreactivity of the most unique sequences in this polypeptide. Synthetic peptides from the two regions of least sequence homology that occur between Sm N and Sm B/B', a dodecamer (amino acid residues 179-190 containing five substitutions) and an undecamer (residues 203-213 containing four substitutions) were coupled to a carrier protein. These conjugates were used to quantify IgG anti-peptide antibodies in sera from patients with SLE. Of 43 sera with anti-Sm specificity, six bound to the B/B' 179-190 peptide but not to the N version. None of 17 anti-Sm-negative SLE sera bound these peptides. The second region of least sequence homology between N and B/B' (203-213) was not antigenic. Our data suggest that a subset of SLE patients with anti-Sm reactivity have IgG autoantibodies capable of discriminating between Sm N and SmB/B' polypeptides by binding a previously unreported SmB/B'-specific autoepitope. The data also indicate that brain and heart-specific anti-Sm antibodies do not exist in SLE sera, suggesting that these tissues do not participate in the induction or maintenance of the autoimmune anti-Sm response.

Amino Acid Sequence↗
PubMed1993

Increased limb involvement in murine collagen-induced arthritis following treatment with anti-interferon-gamma.

We have tested the effect of administering H22, a hamster neutralizing MoAb to murine interferon-gamma (IFN-gamma) in collagen-induced arthritis. Mice were immunized with human type II collagen in adjuvant on day 1 and boosted with soluble collagen on day 21. H22 was administered (250 micrograms, intraperitoneally) either during the induction of arthritis (on days 0, 6, 13 and 20) or around the time of disease manifestation (on days 21, 28, 35 and 42). Control mice received either an isotype-matched non-neutralizing MoAb or saline. Both treatment regimes gave similar results. Treatment with H22 did not significantly affect the incidence of arthritis, time of onset, degree of oedema, histopathological severity, or level of anti-type II collagen IgG. However, a highly significant increase (P < 0.01) in the number of limbs affected by arthritis was observed in the H22-treated group, irrespective of whether the antibody was administered during the induction of arthritis, or during the time of clinical manifestation of disease. From these results it was concluded that anti-IFN-gamma treatment caused an increase in the number of arthritic lesions, but did not affect the severity of each individual lesion.

Animals↗
PubMed1993

Cell-mediated pathology during murine malaria-associated nephritis.

We have studied the cellular mechanisms involved in the development of nephritis during acute and chronic murine malaria infections induced by Plasmodium vinckei petteri and P. berghei respectively. Albuminuria and uraemia were observed during the early stages of both types of infection, and were associated with glomerular and interstitial hypercellularity. There was a gradual increase in numbers of CD45+ cells from the early stages of both infections onwards. These infiltrates contained CD4+ and CD8+ cells and mononuclear phagocytes. The interstitial and glomerular hypercellularity was due to an influx of inflammatory cells rather than an increase in renal cell division. These findings indicate the importance of cell-mediated immune mechanisms in the development of nephritis during murine malaria and illustrate an example of naturally occurring infection-induced nephritis.

Acute Disease↗
PubMed1993

Effect of beta-blocker therapy on serum lipoprotein profiles in patients on renal dialysis and in diabetic nephropathy.

We determined whether the serum lipoprotein levels in insulin-dependent diabetic patients (IDDM) with nephropathy and in patients on haemodialysis or continuous ambulatory peritoneal dialysis were affected by beta-blocker therapy. A case control study was performed in 18 IDDM patients with diabetic nephropathy, in 18 patients receiving chronic haemodialysis (HD) and 16 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). In IDDM patients with diabetic nephropathy very low density lipoprotein-cholesterol (VLDL-CHOL) (0.680 +/- 0.17 vs 0.197 +/- 0.04 mmol/l, p = 0.004), total triglycerides (1.71 +/- 0.23 vs 0.808 +/- 0.14 mmol/l, p = 0.004) and very low density lipoprotein triglyceride (VLD-TG) were higher in the beta-blocker therapy group. In haemodialysis patients, beta-blocker therapy caused no significant changes in the serum lipoprotein profiles compared to the control group. In patients receiving continuous ambulatory peritoneal dialysis VLDL-CHOL was significantly higher (1.47 +/- 0.24 vs 1.08 +/- 0.21 mmol/l, p = 0.042) and cholesterol-high density lipoprotein (HDL-CHOL) was lower in the beta-blocker therapy group. The elevated VLDL-CHOL level (0.96 +/- 0.12 vs 1.24 +/- 0.14 mmol/l, p = 0.021) was correlated with the duration of CAPD in patients receiving beta-blocker therapy. Antihypertensive therapy with beta-blockers in IDDM patients with persistent proteinuria and in patients on continuous ambulatory peritoneal dialysis appears to adversely effect serum lipoproteins which may add to their cardiovascular risk.

Adrenergic beta-Antagonists↗
PubMed1992

Anti-type II collagen ELISA. Increased disease specificity following removal of anionic contaminants from salt-fractionated type II collagen.

The purification of type II collagen, for the detection of anti-type II collagen antibodies by ELISA procedures, involves removal of proteoglycans by guanidine-HCl, followed by pepsin solubilisation and salt fractionation. However, type II collagen purified in this way may contain contaminants, despite the apparent purity on SDS-polyacrylamide gels. In this paper we demonstrate how additional purification by DEAE chromatography reduces the degree of background binding in the type II collagen ELISA, leading to an increase in disease specificity. The contaminants included proteoglycan and bound serum IgG from both rheumatoid arthritis (RA) patients and healthy controls in ELISA. Furthermore, positive correlations were observed in the sera (n = 24) between degree of reactivity to the contaminants and to (1) purified proteoglycan (r = 0.50, P = 0.01) and (2) pepsin (r = 0.65, P = 0.001). Thus, inadequate purification of type II collagen produces false positive reactions in the collagen ELISA and gives rise to a high background. A lack of specificity has been frequently associated with this assay.

Adolescent↗
PubMed1992

T and B cell responses following immunization with tetanus toxoid in IgA nephropathy.

The B and T cell responses were investigated in IgA nephropathy before and after immunization with tetanus toxoid (TT). Both IgA and IgG anti-tetanus toxoid antibodies were elicited, but the IgA antibodies were significantly greater in patients (92.6 +/- 11.7 ELISA units) than in the controls (49.2 +/- 7.5 ELISA units). This was associated with a significantly greater proportion of IgA+ B cells in patients than controls before immunization. However, a significant increase in the proportion of IgA1 binding CD4 and CD8 cells was also found. The proportion of CD3 cells with gamma delta T cell receptors (CD3+TCR gamma delta +), was significantly greater before immunization in the IgA nephropathy patients (37.0% +/- 2.4), compared with controls (10.0% +/- 2.3; P less than 0.001). Immunization with TT further enhanced the CD3+TCR gamma delta + cells in patients to 45.8% +/- 7.2 compared with controls (16.3% +/- 4.5), with a corresponding decrease in CD3+TCR alpha beta + cells in the patients (P less than 0.001). CD3+TCR gamma delta + cells are upregulated by common microbial antigens and clinical exacerbations of IgA nephropathy are frequently associated with mucosal infections and a rise in serum IgA concentration. The increased TCR gamma delta expression may be responsible for the enhanced IgA antibody response in IgA nephropathy. The increase in IgA antibodies may than exert a controlling effect by binding to augmenting T cells and thereby inhibiting their function.

Adult↗
PubMed1992

Successful transfer of collagen-induced arthritis to severe combined immunodeficient (SCID) mice.

We describe the adoptive transfer of erosive arthritis to an immunodeficient host. Spleen cells from arthritic DBA/1 mice (H-2q), immunized 4-6 weeks previously with bovine type II collagen in adjuvant, were transferred intraperitoneally into SCID mice (H-2d). SCID recipient mice also received native or denatured type II collagen (100 micrograms intraperitoneally) at the time of cell transfer. Arthritis developed in five out of five mice approximately 2 weeks after injection of cells plus native collagen, whereas animals injected with cells plus denatured collagen did not show any clinical or histological evidence of arthritis. The minimum graft size required for successful transfer of arthritis was established at 10(7) DBA/1 spleen cells. Histological examination of the joints of arthritic SCID recipient mice revealed synovitis, fibrosis and erosion of cartilage and underlying bone. Mean circulating levels of anti-type II collagen IgG were found to be significantly higher in mice injected with native collagen than those injected with denatured collagen (40 micrograms/ml and less than 1 microgram/ml, respectively). The ability to transfer collagen-induced arthritis adoptively should facilitate the study of the cellular requirement and pathological mechanisms involved in the induction of this arthropathy.

Animals↗
PubMed1992

Clinical associations of IgG antibodies to the ribonucleoprotein p67 polypeptide in patients with systemic lupus erythematosus.

The ribonucleoprotein (RNP) p67 antigen was purified from rabbit thymus and used in an enzyme linked immunosorbent assay (ELISA) with low interassay variability to detect IgG antibodies to p67 in patients with autoimmune connective tissue diseases. These antibodies were found in eight (80%) patients with a clinical diagnosis of mixed connective tissue disease (MCTD) but also in 27 (40%) patients with systemic lupus erythematosus (SLE). Sixty six per cent of the 12 patients with SLE with high levels of antibodies to p67 (> 50 U) had three or more features of MCTD, including myositis, fibrosing alveolitis, Raynaud's phenomenon, and sclerodactyly. Antibodies to the p67 RNP were not associated with the presence or absence of renal disease in the patients with SLE. This study suggests that antibodies against the p67 RNP are markers for clinical features of MCTD even in the context of SLE.

Autoantibodies↗
PubMed1992

Antigen-binding diversity of human hybridoma autoantibodies derived from splenocytes of patients with SLE.

The antigen-binding specificity of human hybridoma-derived monoclonal autoantibodies (mAb) was analysed with mAbs derived from the spleens of two patients with active systemic lupus erythematosus (SLE). From one patient 72 mAbs (RSP clones) and from the other 173 mAbs (RT clones) were obtained. The binding specificity of these mAbs was analysed by solid- and fluid-phase ELISA against the autoantigens ssDNA, dsDNA, cardiolipin, SmRNP, histones, Sm-D and SS-B (La) synthetic peptides, and foreign antigens including bacterial polysaccharides. In addition, antinuclear antibody activity and anti-dsDNA binding were confirmed by fluorescence staining methods. Reflecting the patient's serological profile, none of the antibodies from the RSP clones reacted with ssDNA or dsDNA but 12 reacted with cardiolipin. In addition, three mAbs reacted with H4, five with U1 RNP, two with Sm-D peptides and 12 with SS-B peptides. In contrast, from the RT fusion, nine mAbs reacted with ssDNA, HI and SS-B peptides, seven with cardiolipin, four with dsDNA, two with Sm-D peptides and one each with H2A, H3 and H4. In many cases one mAb showed reactivity with more than one antigen: for example, mAb RT 72 binds to ssDNA, dsDNA, cardiolipin, H1, H4 and an Sm-D peptide; RT 6 binds to H1, SmRNP and ubiquitinated histone H2A. However, none of the antibodies showed 'across the board' polyreactivity; indeed, the selectivity of the reactions was notable and marked variation in antibody affinity was recorded. Eight of the mAbs bound to Salmonella typhimurium and two to the Klebsiella polysaccharide K-30.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Analysis of a positive feedback mechanism in the anti-Sm autoantibody response of MRL/MPJ-lpr/lpr mice.

The mechanism of induction of anti-Sm antibodies by passive transfer of anti-Sm mAb in MRL/lpr mice was investigated. No idiotypic relationship was detected between the inducing monoclonal antibody KSm2 and either the induced circulating anti-Sm antibodies or the products of anti-Sm-producing hybridomas derived from spleen cell fusion of treated mice. Treatment of mice with ribonucleoprotein Sm antigen, alone or as an immune complex, induced anti-Sm and anti-ribonucleoprotein antibodies similarly to treatment with KSm2. This suggests that autoantigen contributes to the development of the anti-Sm response in MRL mice.

Animals↗
PubMed1991

Cross reaction of antibodies to a glycine/alanine repeat sequence of Epstein-Barr virus nuclear antigen-1 with collagen, cytokeratin, and actin.

P62 is a synthetic peptide which corresponds to the glycine/alanine repeat sequence of Epstein-Barr virus nuclear antigen-1. It is the main epitope recognised by anti-rheumatoid arthritis nuclear antigen antibodies. It was shown previously that anti-P62 antibodies were raised fourfold in patients with rheumatoid arthritis compared with controls. To examine the possibility that this increase was due to cross reactive autoantibodies binding to P62, anti-P62 antibodies from serum samples taken from 10 patients with rheumatoid arthritis and five healthy controls were purified by affinity chromatography. Immunoglobulin G anti-P62 antibodies purified from four of 10 serum samples from patients with rheumatoid arthritis also reacted with human epidermal keratin, denatured collagen type II and actin, but not with influenza antigens, as determined by enzyme linked immunosorbent assay (ELISA). Anti-P62 antibodies in serum samples from healthy controls and patients with rheumatoid arthritis reacted with epidermal keratin by immunoblotting. It is suggested that antibodies to the glycine/alanine repeat sequence of Epstein-Barr nuclear antigen-1 recognise homologous epitopes on keratin, actin, and collagen. It is also possible that molecular mimicry between a major epitope on the Epstein-Barr virus and several autoantigens might contribute to the breakdown of tolerance and autoimmunity in patients with rheumatoid arthritis.

Actins↗
PubMed1990

Recurrence of focal segmental glomerulosclerosis in transplanted kidneys: analysis of incidence and risk factors in 59 allografts.

Fifty-nine allografts were placed in 43 patients with renal failure from focal segmental glomerulosclerosis (FSGS): 27 allografts were put into 16 children aged less than 15 years, and 32 allografts into 27 adolescents and adults. Recurrence of FSGS was noted histologically in 13 allografts, 10 in 8 children and 3 in adults. None of the 9 children and 24 adults who never developed an allograft nephrotic syndrome showed FSGS in their allograft biopsies. The age of onset was a strong risk factor for recurrence: recurrent FSGS developed in 8 of 16 children (50%) but only in 11% of adolescents and adults (3 of 27 patients). Although the time from apparent onset to renal replacement treatment was shorter in those with recurrence than those without in the children, there was no difference in the time spent on dialysis prior to transplantation. Mesangial prominence was observed in the original biopsy in 12 of 13 patients with recurrence, and recurrence rate was similar in living and cadaver donor allografts; class I MHC matching was similar in those with and without recurrence. Three allografts treated with cyclosporin A as well as 9 with azathioprine showed recurrence. Of 9 second or subsequent allografts placed in those with recurrence in the first allograft, only 3 showed further recurrence. In 3 re-grafted after 13, 11 and 5 years, normal function was seen.

Adolescent↗