Biomedical subjects

M J Rowley

Publications and source records attributed to M J Rowley.

At least 73 records · Page 4Linked to original sources

PubMed1995

Prevalence of antibodies to glutamic acid decarboxylase in women who have had gestational diabetes.

OBJECTIVES: Our purpose was to determine the prevalence of autoantibodies to glutamic acid decarboxylase in women who had had gestational diabetes, including those in whom insulin-requiring or non-insulin-requiring diabetes mellitus has since developed. STUDY DESIGN: The study group comprised 734 women with previous gestational diabetes who were consecutive attendees to a follow-up clinic. These women were tested for autoantibodies to glutamic acid decarboxylase with a radioimmunoprecipitation assay. We similarly tested 104 women in whom permanent diabetes mellitus developed after gestational diabetes, of whom 20 were using insulin and 84 were not. Those using insulin also had fasting C-peptide levels measured. RESULTS: Thirteen of the 734 (1.8%, 95% confidence interval 0.9% to 3.0%) women with previous gestational diabetes were positive for autoantibodies to glutamic acid decarboxylase. Of the 20 women with diabetes treated with insulin, 12 had insulin deficiency confirmed by low levels of C peptide; all 12 were positive for autoantibodies to glutamic acid decarboxylase. Of the 84 women with diabetes not requiring insulin, 6 (7.1%, 95% confidence interval 2.7% to 14.9%) were positive for autoantibodies to glutamic acid decarboxylase. CONCLUSIONS: The prevalence of autoantibodies to glutamic acid decarboxylase in women with previous gestational diabetes was 1.8%. Our data also showed that insulin-dependent diabetes mellitus will develop in 1.7% of women with gestational diabetes. A positive test for autoantibodies to glutamic acid decarboxylase may help in the early identification of insulin-dependent diabetes mellitus. Adult-onset insulin-dependent diabetes mellitus developed in only 5.2% (12/230) of women with previous gestational diabetes who later had diabetes mellitus.

Adult↗

PubMed1995

Hypopigmented macules in acantholytic disorders.

BACKGROUND: Widespread hypopigmented macules are rarely seen in heavily pigmented patients with Darier's disease. Previous hypotheses concerning the cause of decreased pigmentation suggest it is a postinflammatory phenomenon or that the hypomelanosis is evidence of subclinical acantholysis. PATIENTS: This report presents 2 patients: a new case of disseminated guttate leukoderma in a black patient with Darier's disease and the first such case in a patient with transient acantholytic dermatosis (Grover's disease). Direct immunofluorescence and electron-microscopic studies were carried out on lesional biopsies. OBSERVATIONS: Numerous small hypopigmented macules were observed in two black patients followed for acantholytic disorders. Three biopsies of the hypopigmented macules revealed acantholysis, while one showed only decreased melanin. Direct immunofluorescence studies were negative. Electron-microscopic studies of the leukodermic macules showed sparse melanocytes and melanosomes that were mostly pigmented stage IV melanosomes. CONCLUSIONS: Disseminated guttate leukoderma can occur in transient acantholytic dermatosis, as well as in Darier's disease. It is readily apparent on darkly pigmented skin because of contrast. The etiology of this phenomenon is still unknown.

Acantholysis↗

PubMed1995

Pancreatic islet cell cytoplasmic antibody in diabetes is represented by antibodies to islet cell antigen 512 and glutamic acid decarboxylase.

The presence of serum islet cell cytoplasmic antibodies (ICAs) is a standard autoimmune marker for insulin-dependent diabetes mellitus (IDDM). The antigenic molecule(s) responsible for ICA has not been identified, although antibodies to the 65-kDa isoform of glutamic acid decarboxylase (GAD65) do contribute. We tested 129 IDDM sera for antibodies to ICA512 (anti-ICA512), antibodies to GAD (anti-GAD), and ICAs; we tested for inhibition of ICAs with purified recombinant ICA512 and sheep brain GAD; and we tested for immunofluorescence reactivity on COS7 cells transfected with cDNA clones encoding ICA512 and GAD65. The results were that anti-ICA512 antibodies contribute to ICA reactivity and that these, in combination with anti-GAD antibodies, account for most ICA reactivity in IDDM. Anti-ICA512 antibodies were present at a frequency of 51% in 61 patients with early-onset IDDM (age of onset < or = 20 years) of short duration (< or = 1 month) but only in 9% of 68 patients with an onset age of > 20 years and/or a disease duration of > 1 month. The frequency of anti-GAD antibodies in these sera was similar irrespective of duration or age of onset. Anti-ICA512 and anti-GAD antibodies were demonstrable by indirect immunofluorescence on transfected COS7 cells, and ICA could be inhibited using either recombinant ICA512 or purified brain GAD. We conclude that anti-ICA512 and anti-GAD antibodies contribute to ICA reactivity and that anti-ICA512 antibodies account for the increased frequency of ICA reactivity in early-onset IDDM of short duration.

Adolescent↗

PubMed1994

Antibodies to glutamic acid decarboxylase and diabetes mellitus in the Multiple Risk Factor Intervention Trial.

Diabetes mellitus is a heterogeneous disease. The better classification of types of diabetes mellitus among adults will improve epidemiologic studies of determinants of risk factors and genetic host susceptibility. Recently, an antibody to a specific enzyme, glutamic acid decarboxylase, has been closely linked to insulin-dependent diabetes mellitus. Sera were collected at baseline between 1972 and 1974 from initially nondiabetic participants in the Multiple Risk Factor Intervention Trial. After approximately 18 years of frozen storage, the serum samples were tested for antibodies to glutamic acid decarboxylase (anti-GAD) in 175 men who developed diabetes and 352 matched controls who did not develop diabetes during the 6-year follow-up. Nine of the 527 samples tested had elevated (19 or more units) titers of anti-GAD. Six of the nine men with elevated anti-GAD subsequently developed diabetes, and three of these six were ultimately placed on insulin therapy. These data suggest that elevated levels of anti-GAD may be a prospective marker for the subsequent development of insulin-dependent diabetes mellitus. The measurement of anti-GAD is relatively easy, can be performed in stored serum specimens, and may be used in epidemiologic studies to enhance the understanding of the determinants of diabetes mellitus.

Adult↗

PubMed1994

Antibodies to glutamic acid decarboxylase as predictors of insulin-dependent diabetes mellitus before clinical onset of disease.

We have done a study designed to ascertain the effectiveness of measuring antibodies to glutamic acid decarboxylase (anti-GAD) in predicting insulin-dependent diabetes mellitus (IDDM). Anti-GAD was measured in prediabetic sera from 151 women aged 20-39 years with newly diagnosed diabetes mellitus who had been identified through a nationwide diabetes register. Multiple serum samples had been collected from these women up to 10 years before the clinical onset of diabetes during their earlier pregnancies. Anti-GAD was measured with a radioimmunoprecipitation assay. Anti-GAD was detected in 82% of 28 women with IDDM, in 36% of 11 women with non-insulin-dependent diabetes mellitus, and in 5% of 112 women with gestational diabetes mellitus. In a random sample of 100 non-diabetic young Finnish women, none had anti-GAD. The sensitivity of the anti-GAD assay for predicting IDDM was 82.1% and the specificity was 100%. The longest time of anti-GAD positivity before clinical onset of IDDM was 10 years. Once positive, anti-GAD levels remained stable and no patients became negative after a positive test during the prediabetic period. Anti-GAD is a valuable early predictive marker and is associated with a very high risk for development of IDDM.

Adult↗

PubMed1994

Autoantigenic properties of native and denatured glutamic acid decarboxylase: evidence for a conformational epitope.

The frequency of antibodies to GAD (anti-GAD) in insulin-dependent diabetes mellitus (IDDM) varies greatly according to the type of assay employed. We therefore examined the immunoassay characteristics of diabetic sera using GAD purified from porcine brain and shown to contain both isoforms. Sera from 38 patients with IDDM, including 1 patient with both stiff-man syndrome (SMS) and IDDM, were studied for anti-GAD by radioimmunoprecipitation (RIP), Western blotting, and dot-blotting. The sera were selected according to reactivity in the RIP assay. There was a good correlation between potency of the RIP reaction at the screening dilution of 1:2 and the endpoint dilution in the assay which ranged from 1:2 to 1:30,000 for IDDM sera, and 1:300,000 for the SMS serum. Of the 38 sera positive for anti-GAD by RIP, only 6 had antibodies detectable by Western blotting, and all gave an RIP titer of at least 1:250. The low frequency of antibodies by Western blotting was explicable by denaturation of the antigen. Thus, using a dot-blotting assay in which reactivity to untreated "native" GAD was compared with reactivity to GAD after denaturation by reduction with 2-mercaptoethanol and boiling, 20 of the 38 IDDM sera reacted unequivocally with the native GAD compared with only 2 that reacted with denatured GAD after reduction and boiling. The sera were tested for their capacity to inhibit the catalytic activity of GAD, but only the high-titer serum from the patient with SMS did so. Our study further validates the RIP assay for anti-GAD and establishes that anti-GAD exists in IDDM over a wide range of titers that correlate with other assay characteristics, and also indicates that the conformational autoantibody epitope on GAD is susceptible to alteration under denaturing conditions.

Adolescent↗

PubMed1994

Antibodies to the collagen-like region of C1q and type II collagen are independent non-cross-reactive populations in systemic lupus erythematosus and rheumatoid arthritis.

The collagen-like region (CLR) of the first component of complement, C1q, and type II collagen are structurally similar, raising the possibility of epitopes in common, and of the existence of autoantibodies that are cross-reactive. Accordingly, antibodies to the CLR of C1q and to type II collagen were measured in patients' sera with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) by an ELISA. IgG antibodies to the CLR of C1q were present in 17% of patients with SLE but none with RA, and IgA antibodies were present in 10% and 8% of patients with SLE and RA, respectively. IgG antibodies to type II collagen were present in 15% and 25% of patients with SLE and RA, respectively, and IgA antibodies in 15% and 28% of patients with SLE and RA, respectively. There was no correlation in either disease between the serum levels of antibodies to the CLR of C1q and antibodies to type II collagen. For sera with antibodies to both antigens, neither competitive inhibition by ELISA nor preabsorption with the alternative antigen affected the level of reactivity to the other antigen. Thus antibodies to the CLR of C1q and antibodies to type II collagen are independent and non-cross-reactive populations, and presumably occur by different types of immunogenic stimulation.

Antibody Specificity↗

PubMed1994

Antibodies to collagen: comparative epitope mapping in women with silicone breast implants, systemic lupus erythematosus and rheumatoid arthritis.

Women with silicone breast implants have a significantly increased frequency of antibodies to collagen types I and II. To characterize the specificity of these antibodies, 70 women without a specific autoimmune disease, according to the criteria of the American College of Rheumatology, but who had silicone breast implants were studied for the presence of serum antibodies to native and denatured human types I and II collagen by ELISA. Positive sera were further studied by immunoblotting using peptides derived by cyanogen bromide digestion of the collagens. Samples of 82 women with systemic lupus erythematosus (SLE), 94 women with rheumatoid arthritis (RA), and 133 healthy controls were studied concurrently. There was a high frequency of autoantibodies to collagen in each of the study groups when compared to the healthy controls. However, and of particular interest, the epitope specificity of the autoantibodies differed markedly. Sera from women with silicone implants reacted strongly in an individual-specific manner with multiple peptides of type I collagen, whereas sera from women with SLE and RA reacted only weekly with a restricted range of peptides of type I collagen. Sera from women with RA reacted strongly with multiple peptides of type II, whereas sera from women with silicone implants or SLE reacted only weakly. The reactivity of women with silicone implants suggests that silicone or its biodegradation products can act as adjuvants in situ to enhance the immunogenicity of type I collagen, or protein-silicone conjugates.

Arthritis, Rheumatoid↗

PubMed1994

Anti-glutamate decarboxylase and other antibodies at the onset of childhood IDDM: a population-based study.

Sera obtained at diagnosis from 273 children (0-14 years) with insulin-dependent diabetes mellitus (IDDM) were studied to compare different autoantibody levels. The subjects comprise 75% of all incident cases in New South Wales, Australia, for a 2-year period (ascertainment > 99% complete). Antibodies against glutamate decarboxylase were measured by radioimmunoprecipitation, insulin autoantibodies (on 176 sera collected within 4 days of initiation of insulin therapy) by radioimmunoassay, thyroid peroxidase and antigliadin IgA antibodies by enzyme-linked immunoassay, and anti-endomysial IgA and islet cell antibodies by indirect immunofluorescence. Reference ranges for anti-glutamate decarboxylase and insulin autoantibodies were determined in a group of non-diabetic children. Of the sera 69% were positive for anti-glutamate decarboxylase, 65% for insulin autoantibodies, 71% for islet cell antibodies (> or = 20 Juvenile Diabetes Foundation units), 10% for anti-thyroid peroxidase, 2.6% for antigliadin and 3.0% for anti-endomysial antibodies. Islet cell antibodies and insulin autoantibodies were both negative in 13.7% of the sera, while only 5.8% were negative for all three of islet cell antibodies, insulin autoantibodies and anti-glutamate decarboxylase. There was a higher frequency of anti-glutamate decarboxylase among girls than boys (75% vs 63%, p = 0.03) and a negative correlation between the level of insulin autoantibodies and age at diagnosis (r = -0.41, p < 0.0001). A higher frequency of antithyroid peroxidase was found with increasing age (p = 0.05). Higher titres of islet cell antibodies were associated with a higher frequency of both anti-glutamate decarboxylase (p < 0.0001) and insulin autoantibodies (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1994

Lack of antibodies to glutamic acid decarboxylase in young adults of the high diabetes prevalence Wanigela people of Papua New Guinea.

Antibodies to glutamic acid decarboxylase (anti-GAD) are common in typical insulin-dependent diabetes mellitus, and also identify a sub-group of older persons who are originally misdiagnosed as having non-insulin-dependent disease (NIDDM). The Wanigela people of Papua New Guinea are highly susceptible to diabetes mellitus, with a prevalence of 20.4% in urbanised young adults aged 25-34 years. On the basis of clinical features including the presence of obesity and relatively high insulin concentrations the Wanigelas have NIDDM. To determine whether anti-GAD is present in this high prevalence form of diabetes, and to investigate whether there might be an autoimmune component to the disease, we measured anti-GAD in 93 newly-diagnosed diabetic subjects aged 25-44 years, and in 40 controls with normal glucose tolerance. There was no difference in mean levels of anti-GAD in diabetic subjects and normal controls. Two subjects had borderline elevated anti-GAD levels: one was a normal control, and the other a diabetic. This study shows that anti-GAD is not present in this (and probably other) high prevalence variant of NIDDM. Moreover, the results suggest strongly that diabetes in the Wanigela people is unlikely to have an autoimmune component to its pathogenesis.

Adult↗

PubMed1994

Latent autoimmune diabetes mellitus in adults (LADA): the role of antibodies to glutamic acid decarboxylase in diagnosis and prediction of insulin dependency.

Type 1 diabetes mellitus in adults may present in a manner similar to that of Type 2 diabetes but with a late development of insulin dependency. We studied 65 patients who presented with 'adult-onset' diabetes after the age of 30 years. Of these patients, 19 required insulin therapy. The insulin-treated patients were significantly younger, their onset of diabetes was at an earlier age, and their postprandial serum C-peptide levels were lower than those of the non-insulin-treated group. Moreover, the insulin-treated subjects had a higher mean concentration of antibodies to glutamic acid decarboxylase (GAD) (66.8 +/- 10.2 units) than the patients who did not require insulin (9.9 +/- 1.9 units) (p < 0.001) and their frequency of anti-GAD positivity was 73.7% versus 4.3% (p < 0.001). Thus, among patients attending a diabetes clinic, the majority (73.7%) of subjects who presented with diabetes after 30 years of age and who subsequently required therapy with insulin, actually have the islet cell lesion of Type 1 diabetes which progresses at a slower tempo than in children. We conclude that testing for anti-GAD in adult-onset non-obese diabetic patients should be a routine procedure in order to detect latent insulin-dependency at the earliest possible stage, since this assay can assist in the correct classification of diabetes, and more appropriate therapy.

Adult↗

PubMed1994

Autoantibodies to glutamic acid decarboxylase and insulin in islet cell antibody positive presymptomatic type 1 diabetes mellitus: frequency and segregation by age and gender.

The frequency of antibodies to glutamic acid decarboxylase (GAD) and insulin (IAA) in presymptomatic Type 1 diabetes mellitus with a positive test for antibodies to islet cell antigen (ICA) was examined. Thirty-two persons positive for ICA (> 10 JDF units) were tested 2 to 48 months before their ascertained onset of Type 1 diabetes. ICA was quantitated by immunofluorescence as JDF units, anti-GAD by radioimmunoprecipitation and anti-insulin by radioimmunoassay. There was a positive test for anti-GAD in 25 (78%), and for IAA in 23 (72%), of the 32 prediabetic ICA-positive subjects. Stratification according to age at the onset of diabetes showed differing frequencies of anti-GAD and IAA in the prediabetic stage. Thus the positivity rate for anti-GAD for 18 subjects older than 10 years at onset of diabetes was 83%, and for 14 aged 10 or younger at onset was 71%; conversely, the rate for IAA for 18 subjects older than 10 at onset was 56% and for 14 aged 10 or less at time of onset was 93% (p = 0.01). The frequency of anti-GAD was higher in females (88%) than males (71%) whereas the frequency of IAA was higher in males (82%) than in females (60%). Since autoantibodies to GAD and insulin occur in presymptomatic Type 1 diabetes with differences in frequencies by age and gender, the stimuli to autoimmunity may operate differently at different ages, and may also be gender-related.

Adolescent↗

PubMed1994

GAD antibody negative NIDDM in adult black subjects with diabetic ketoacidosis and increased frequency of human leukocyte antigen DR3 and DR4. Flatbush diabetes.

The objective of this study is to understand the metabolic and immunologic basis of diabetes in adult blacks with diabetic ketoacidosis (DKA). Twenty-one black adults presenting with DKA ([mean +/- SD] blood pH = 7.18 +/- 0.09, plasma glucose = 693 +/- 208 mg/dl, and positive serum ketones) had a subsequent clinical course of non-insulin-dependent diabetes mellitus (NIDDM). Human leukocyte antigens (HLAs) DR and DQ and antibodies to glutamic acid decarboxylase (GAD) and islet cell cytoplasmic proteins (ICP) were measured to assess autoimmunity. Insulin action was evaluated by the euglycemic insulin clamp, and insulin secretion was measured by C-peptide responses to oral glucose. Ketoacidosis was treated with insulin. Two subjects had a precipitating illness; four had a history of NIDDM. At the time of study, subjects' glycemic control was good (HbA1c = 5.7 +/- 1.6%). Nine subjects were treated with insulin, and 12 were on either sulfonylurea treatment or diet alone. Men (n = 12) were younger than women (n = 9) (40.8 +/- 9.8 and 51.1 +/- 6.3 years of age, respectively, P < 0.05) but similar in body mass index (27.8 +/- 2.7 and 29.98 +/- 4.1 kg/m2, respectively). Antibodies to GAD and ICP were absent. All but one subject was insulin resistant compared with normal subjects (glucose disposal 3.56 +/- 0.04 vs. 6.86 +/- 0.02 mg.kg-1.min-1), and insulin secretion was lower. HLA DR3 and DR4 frequency was higher than in nondiabetic black control subjects (65 vs. 30%, P < 0.012).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Specificity of antibodies to type II collagen in early rheumatoid arthritis.

OBJECTIVE: To analyze the antibody response to native type II collagen in early rheumatoid arthritis (RA), examining the immunoglobulin isotypes, and polypeptide epitopes recognized, in patients followed over a 2-year period from within 6 months of the first occurrence of symptoms. METHODS: Sera from 16 patients were studied, of whom 10 had antibodies to native type II collagen and 6 did not. The clinical and laboratory assessment, carried out initially and at 6 monthly intervals included the number of 1958 ARA criteria fulfilled, Ritchie index, erythrocyte sedimentation rate, rheumatoid factor and radiological assessment. An ELISA was used to measure IgG, IgA and IgM antibodies, and immunoblotting to identify the number and location of epitopes, using polypeptides prepared by cyanogen bromide digestion of human type II collagen. RESULTS: Antibodies to type II collagen were present in all sequential serum samples for the 10 antibody positive patients. None of the 6 patients who initially lacked antibodies developed them. The antibodies were of IgG isotype in 9, of IgA isotype in 8, and of IgM isotype exclusively in one. At the initial clinical assessment patients with antibodies to collagen were indistinguishable from those without. At 12 and 24 months patients with antibodies fulfilled significantly more ARA criteria than antibody negative patients. The patterns of antibody reactivity to collagen polypeptides by immunoblotting were constant over time but differed from patient to patient. CONCLUSION: The presence of an established and persisting IgG antibody response to type II collagen in early RA before cartilage destruction is evident points to a subset of RA, perhaps equivalent to the collagen induced model in animals, in which this immune response is intrinsic to pathogenesis.

Adult↗

PubMed1994

Enzyme inhibitory autoantibodies to pyruvate dehydrogenase complex in primary biliary cirrhosis: applications of a semiautomated assay.

Sera from patients with primary biliary cirrhosis inhibit the activity of the mitochondrial pyruvate dehydrogenase complex. We utilized this effect to develop a simple, miniaturized, semiautomated spectrophotometric assay as a diagnostic aid. The sera studied were from 71 patients with primary biliary cirrhosis and 62 other subjects. The assays included enzyme inhibition, immunofluorescence on HEp-2 cells, enzyme-linked immunosorbent assay using recombinant pyruvate dehydrogenase complex-E2 and immunoblotting on bovine heart mitochondria. With the 71 primary biliary cirrhosis sera, on which M2 antibody was detected by immunofluorescence in 64 (90%), antibodies against pyruvate dehydrogenase complex were detected in 53 (83%) by means of enzyme inhibition, in 57 (89%) by means of enzyme-linked immunosorbent assay and in 60 (94%) by means of immunoblotting. Of the 64 sera positive by immunofluorescence, 60 reacted with pyruvate dehydrogenase complex-E2 on immunoblotting, and the miniaturized enzyme inhibition assay was positive in 53 of these. The enzyme inhibition assay and enzyme-linked immunosorbent assay were calibrated to give a specificity of 100%. At this level, the sensitivities for detection of pyruvate dehydrogenase complex antibody were 83% and 87%, respectively. We found no significant changes in levels of reactivity with the enzyme inhibition assay or enzyme-linked immunosorbent assay according to disease stage. Treatment with cyclosporine was accompanied by a significant decrease in levels of antibody to pyruvate dehydrogenase complex-E2 that matched improved indexes of biochemical liver function.(ABSTRACT TRUNCATED AT 250 WORDS)

Autoantibodies↗

PubMed1994

Enzyme inhibitory autoantibodies to pyruvate dehydrogenase complex in primary biliary cirrhosis differ for mammalian, yeast and bacterial enzymes: implications for molecular mimicry.

Primary biliary cirrhosis is a chronic autoimmune disease in which serum autoantibodies against the mitochondrial 2-oxo acid dehydrogenase enzyme complexes (M2 antibodies) are regularly present. Molecular mimicry of host proteins by bacterial counterparts is a suggested explanation for the origin of these autoantibodies. We tested this hypothesis by measuring the functional reactivity of serum autoantibodies by means of an enzyme inhibition assay against pyruvate dehydrogenase complex from different sources: mammalian, Saccharomyces cerevisiae and Escherichia coli. The 10 primary biliary cirrhosis sera all reacted on immunofluorescence study for M2 antibodies and on immunoblotting with the pyruvate dehydrogenase complex E2 subunit from each of the three enzymes, but there were strikingly different inhibitory capacities. The primary biliary cirrhosis sera were highly inhibitory for mammalian pyruvate dehydrogenase complex (10 of 10 inhibitory; mean level of inhibition, 99%), moderately inhibitory for yeast pyruvate dehydrogenase complex (10 of 10 inhibitory; mean level, 70%) and weakly inhibitory for Escherichia coli pyruvate dehydrogenase complex (4 of 10 inhibitory; mean level, 26%). Thus, with a functional assay that depends on epitope recognition of primary biliary cirrhosis sera, cross-reactivity between mammalian and bacterial pyruvate dehydrogenase complex enzymes is low and molecular mimicry, at least at the B-lymphocyte level, is not supported.

Animals↗

PubMed1993

Autoreactive MHC-restricted cytotoxic cells in BALB/c mice after novel immunisation with a conserved mammalian autoantigen.

We investigated whether a novel immunisation scheme using an endogenous protein could stimulate an autoreactive cytolytic response. The protein selected was porcine dihydrolipoamide dehydrogenase, the E3 component of the mitochondrial 2-OADC enzyme family, because it is structurally conserved in mammals and ubiquitously expressed. Recombinant insulin was used as an alternative antigen. Female BALB/c mice were injected with adjuvant-free syngeneic lymphoid cells that had been exposed to E3 in hypertonic medium to facilitate its pinocytosis and were given two booster injections. Effector lymphoid cells from immunised mice were cultured in vitro with irradiated syngeneic cells that had been treated with hypertonic medium, either with or without antigen. Cytolytic effector cells were detected that lysed isogeneic and not allogeneic target cells, but only from mice immunised with E3. This experimental system provides a new model for the early stages of the development of autoimmunity.

Animals↗

PubMed1993

Subclasses of immunoglobulins and autoantibodies in autoimmune diseases.

The differing capacity of subclasses of IgG to bind to protein A and protein G was used in a sequential affinity purification procedure to examine immunoglobulin isotypes and subclasses in autoimmune disease. The utility of the procedure is that affinity-purified fractions containing particular isotypes and subclasses of immunoglobulin can be analyzed for their content of autoantibodies using standard techniques. For each of four autoimmune diseases studied, chronic active hepatitis, Sjogren's syndrome, primary biliary cirrhosis, and rheumatoid arthritis, there were characteristic protein elution profiles and the various disease-specific autoantibodies showed preferential distributions among the isotypes and subclasses. Moreover there was not an absolute correlation between an increased level of a particular subclass and the occurrence of antibodies of that subclass. The occurrence of highly disease-specific immunoglobulin subclass profiles suggests that the hypergammaglobulinemia associated with autoimmunity cannot be attributed entirely to polyclonal B-cell activation. Rather, there are disease-specific alterations in isotype subclass switching which may reflect different cytokine-dependent influences on autoimmune B cells and their products.

Antibody Specificity↗