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Combined use of autoantibodies (IA-2 autoantibody, GAD autoantibody, insulin autoantibody, cytoplasmic islet cell antibodies) in type 1 diabetes: Combinatorial Islet Autoantibody Workshop.

The aim of this workshop was to assess the ability of individual autoantibody (ab) assays and their use in combination to discriminate between type 1 diabetic and control sera. Coded aliquots of sera were measured in a total of 119 assays by 49 participating laboratories in 17 countries. The sera were from 51 patients with new onset type 1 diabetes and 101 healthy control subjects with no family history of diabetes. In the final analysis, data on diabetic sera were restricted to 43 subjects younger than age 30 years. The laboratories were asked to report results for these sera using their currently available anti-islet autoantibody assays. In addition, they were asked to combine information from their assays to classify sera as having high, moderate, or low probability of originating from a patient with type 1 diabetes. Actual strategies for combining assays were determined by each laboratory. There were no significant differences in sensitivity among 19 radioimmunoassays (RIAs) for IA-2 autoantibodies (cytoplasmic islet cell antibody [ICA] 512) using different constructs that included the intracellular portion of the molecule (mean sensitivity 73%). However, an enzyme-linked immunosorbent assay (ELISA) using the extracellular portion of the IA-2 molecule did not discriminate between diabetic and control sera. Among GAD autoantibody assays that achieved sensitivity >70%, 26 were RIAs and one was an ELISA. When the sera were ranked according to their autoantibody levels, the concordance for insulin autoantibodies (IAAs) in different laboratories was markedly less than for IA-2ab and GADab. Using a combination of autoantibody assays, several laboratories achieved excellent discrimination between diabetic and control sera (sensitivity up to 80% with false-positive rate of 0%). A variety of strategies for combining information from different assays were successful (e.g., those including and excluding ICA), and no one strategy emerged as clearly superior. In conclusion, IA-2/ICA512 autoantibodies are a marker of type 1 diabetes and can be measured consistently by most assays. Several different strategies for combining assays achieved high sensitivity with a low false-positive rate.

Adolescent↗

Evaluation of islet-specific autoantibodies in Japanese patients with insulin-dependent diabetes mellitus: a comparison between autoantibodies to glutamic acid decarboxylase, autoantibodies to 64 kDa islet cell protein and islet cell antibodies.

Autoantibodies to glutamic acid decarboxylase (GAD), autoantibodies to 64 kDa islet cell protein and islet cell antibodies (ICA) were measured in 79 Japanese patients with insulin-dependent diabetes mellitus (IDDM). The overall prevalences of GAD antibodies, 64K antibodies, and ICA in these patients were 69.6% (55/79), 48.1% (38/79), and 46.8% (37/79), respectively. However, in a subset of these patients with recent onset IDDM (< 1 year) the prevalences of GAD antibodies, 64K antibodies, and ICA were 78.8% (26/33), 66.7% (22/33), and 78.8% (26/33), respectively. Furthermore, the prevalences of GAD antibodies, 64K antibodies, and ICA were significantly decreased in patients with long standing diabetes at 60.9% (28/46), 34.8% (16/46), and 23.9% (11/46), respectively. However, when these patients were divided into two groups by the presence or absence of organ-specific autoimmune disease (OSAD), the mean levels of GAD antibodies and ICA in the patients who gave a positive result were significantly higher in patients with OSAD (397 units and 98 JDF units, respectively) than in patients without OSAD (74 units and 39 JDF units, respectively). These results demonstrate that it is important to evaluate the prevalences and levels of islet-specific autoantibodies when considering disease duration and co-existence of autoimmune disease in patients with IDDM.

Adolescent↗

Proinsulin autoantibodies are more closely associated with type 1 (insulin-dependent) diabetes mellitus than insulin autoantibodies.

The disease association of autoantibodies to proinsulin and insulin was compared in patients with Type 1 (insulin-dependent) diabetes mellitus and first-degree relatives. Following the recommendation of the Fourth International Workshop on the Standardization of insulin autoantibodies, autoantibodies were determined by fluid-phase radioimmunoassay using equimolar concentrations of mono-125I-A14-insulin or -proinsulin to detect insulin or proinsulin autoantibodies, respectively. A higher prevalence of proinsulin autoantibodies vs insulin autoantibodies was found in 97 patients with Type 1 diabetes prior to insulin treatment (34.0% vs 22.7%, p less than 0.05) and in 16 islet cell antibody-positive relatives (43.8% vs 31.3%, NS). There was only one serum positive for insulin and proinsulin autoantibodies in 110 islet cell antibody-negative first degree relatives (0.9%). None of 88 normal sera contained proinsulin autoantibodies or insulin autoantibodies. There was a close correlation of proinsulin autoantibody and insulin autoantibody titres in individual sera (r = 0.95, p less than 0.01) due to crossreaction of all insulin autoantibodies with proinsulin. However, some proinsulin autoantibodies did not crossreact with insulin. Background binding in normal sera was lower for proinsulin autoantibodies. We conclude that proinsulin autoantibodies have a higher association to acute Type 1 diabetes than insulin autoantibodies.

Adult↗

Adrenal-cortex autoantibodies and steroid-producing cells autoantibodies in patients with Addison's disease: comparison of immunofluorescence and immunoprecipitation assays.

Autoimmune Addison's disease and premature ovarian failure are characterized by the presence of organ-specific autoantibodies. The main adrenal and gonadal autoantigens have been identified and cloned, and the relationship between the autoantibodies detected by immunofluorescence techniques and those detected by the new assays using recombinant autoantigens needed to be investigated. We studied 165 patients with Addison's disease: 143 patients had different forms of autoimmune Addison's disease (13 with idiopathic premature ovarian failure) and 22 had nonautoimmune Addison's disease. Adrenal-cortex autoantibodies and steroid-producing cell autoantibodies were measured by the immunofluorescence techniques. Autoantibodies to steroid 21-hydroxylase, 17alpha-hydroxylase, and P450 side chain cleavage enzyme were measured by immunoprecipitation assay using 35S-labeled recombinant proteins. Adrenal-cortex autoantibodies and autoantibodies to 21-hydroxylase were found in 81% of the patients with autoimmune Addison's disease. None of the patients with nonautoimmune Addison's disease had adrenal-cortex autoantibodies or autoantibodies to 21-hydroxylase. A high association between these two markers in patients with different forms of autoimmune Addison's disease and in those with short- or long-standing disease was found. Steroid-producing cells autoantibodies were found in 26% of the patients with autoimmune Addison's disease, and autoantibodies to 17alpha-hydroxylase and/or P450 side chain cleavage enzyme in 36% of the patients. Steroid-producing cells autoantibodies were found in 11/13 (85%) of patients with idiopathic premature ovarian failure associated with autoimmune Addison's disease, and autoantibodies to 17alpha-hydroxylase and/or P450 side chain cleavage were found 12/13 (92%) of patients; the only case negative for all these three markers suffered from Turner's syndrome. Provided that a high standard of immunofluorescence technique is maintained, measurement of adrenal cortex autoantibodies or steroid-producing cells autoantibodies by either immunofluorescence or immunoprecipitation assay is essentially equivalent.

Addison Disease↗

Number of autoantibodies (against insulin, GAD or ICA512/IA2) rather than particular autoantibody specificities determines risk of type I diabetes.

We previously evaluated radioassays for insulin autoantibodies (IAA), glutamate decarboxylase autoantibodies (GAA) and ICA512bdc autoantibodies (ICA512bdcAA) in the prediction of type I diabetes. Among first degree relatives, the five year risk of diabetes was 0% if no autoantibody was positive, 15% if only one was positive, 44% if two were positive and 100% if all three were positive. We measured IAA, GAA and ICA512bdcAA in 45 patients with new onset type I diabetes (sampled within 7 days of insulin therapy), 882 first degree relatives of patients with type I diabetes, and 217 control subjects. ICA512bdc is a construct of the ICA512/IA2 molecule (amino acid residues 256-979), including the intracellular domain. Based on receiver-operating characteristic plots, there was no significant difference between the three assays in their ability to discriminate between disease and control subjects. The upper limits of normal for the assays were determined as the 99th percentile of levels in the control subjects or higher. Using these cut-offs, 76% of new onset patients were positive for two or more autoantibodies, and 98% were positive for one or more. In comparison, none of 198 control subjects tested for all three assays were positive for more than one autoantibody. In relatives with a single autoantibody, or exactly two autoantibodies, there was no difference in diabetes-free survival according to which one of the autoantibodies was present (P = 0.70, logrank test), or which particular combination of autoantibodies was present (P = 0.56, logrank test) respectively. Our conclusions were as follows: the number of autoantibodies (counting IAA, GAA and ICA512bdcAA) is important in prediction, rather than the particular autoantibody specificities present. Among patients with new onset insulin-dependent diabetes, the absence of any of these autoantibodies justifies the consideration of non-autoimmune forms of diabetes in the differential diagnosis.

Adolescent↗

Thyrotropin receptor autoantibodies in serum are present at much lower levels than thyroid peroxidase autoantibodies: analysis by flow cytometry.

Using Chinese hamster ovary (CHO) cells that express high numbers of TSH receptor (TSHR) on their surface, we studied the feasibility of detecting directly by flow cytometry the binding of autoantibodies in patients' sera to the native TSHR. After using a serum (BBI) with high potency in the TSH binding inhibition (TBI) assay to establish the protocol, we studied an additional 38 sera: 10 without TBI activity (1-4.2% inhibition), 10 with moderately high TBI values (17.3-39.4% inhibition), 10 with high TBI levels (52-95.1% inhibition), 4 from normal individuals without autoimmune thyroid disease, and 4 from patients with systemic lupus erythematosus. We observed that a number of sera, including some without thyroid autoantibodies, contain antibodies against unknown antigens on CHO cells. Preadsorption with untransfected CHO cells before addition to the TSHR-10,000 cells eliminated or greatly reduced this nonspecific background. None of the sera from normal individuals, subjects with negative TBI values, or patients with systemic autoimmunity generated a positive signal on flow cytometry with TSHR-10,000 cells relative to the signal on untransfected cells. Remarkably, only 4 of 21 TBI-positive sera (including BBI) unequivocally recognized the TSHR on flow cytometry. In contrast, when thyroid peroxidase (TPO) autoantibodies in the same sera were studied using CHO cells overexpressing TPO on their surface, all 20 sera with TPO autoantibodies clearly elicited positive net fluorescence relative to untransfected cells. Study of the potent serum, BBI, revealed similar fluorescence (approximately 250 U) for TPO autoantibodies and TSHR autoantibodies at dilutions of 1:1000 and 1:10, respectively. Thus, by flow cytometry, the titer of TPO autoantibodies in the BBI serum is about 100-fold higher than that for TSHR autoantibodies in the same serum. In conclusion, the present data provide the strongest support for the idea that TSHR autoantibodies in the sera of patients with autoimmune thyroid disease are present at much lower levels than are TPO autoantibodies. This finding has important implications for the diagnostic detection of TSHR autoantibodies and for understanding the pathogenesis of Graves' disease.

Animals↗

Infliximab treatment does not induce organ-specific or nonorgan-specific autoantibodies other than antinuclear and anti-double-stranded DNA autoantibodies in Crohn's disease.

BACKGROUND: Treatment of Crohn's disease (CD) by infliximab has been associated with the induction of antinuclear (ANA) and anti-double stranded DNA (dsDNA) autoantibodies. As yet, little is known about the effect of the humoral response induced by infliximab on the production of other organ-specific or nonorgan-specific autoantibodies. METHODS: Thirty-five patients with CD treated with repeated infusions of infliximab were prospectively studied. Thirty-two patients with CD who had never received infliximab served as controls. A large panel of autoantibodies directed against phospholipid, beta2-glycoprotein I, mitochondria, smooth muscle, liver--kidney microsomes, filaggrin, thyroid, adrenals, and rheumatoid factor was tested along with ANA and anti-dsDNA autoantibodies during 1 year of intermittent treatment with infliximab. Autoantibodies were detected using the appropriate methods (i.e., indirect immunofluorescence, a radioimmunological technique, and ELISA assays). RESULTS: Induction of ANA and anti-dsDNA autoantibodies was observed in 53% and 35% of infliximab-treated patients with CD, respectively. Overall, no other organ-specific or nonorgan-specific autoantibodies were detected during follow-up. A single patient who developed ANA and anti-dsDNA autoantibodies showed clinical features consistent with drug-induced lupus, which quickly resolved after discontinuation of infliximab. The other patients with CD receiving infliximab did not develop any clinical symptoms of autoimmunity. CONCLUSIONS: The humoral response induced by infliximab was restricted to ANA and anti-dsDNA autoantibodies, which persist for up to 1 year of follow-up. We confirmed the significant prevalence of such autoantibodies induced by infliximab in CD, but they are not generally associated with clinical signs of autoimmunity.

Adult↗

Molecular and cellular basis for pathogenicity of autoantibodies: lessons from murine monoclonal autoantibodies.

The pathogenesis of autoantibody-mediated cellular and tissue lesions in autoimmune diseases is most straightforwardly attributable to the combined action of self-antigen binding properties and effector functions associated with the Fc regions of the different immunoglobulin (Ig) isotypes. The analysis of two different sets of monoclonal autoantibodies derived from lupus-prone mice revealed remarkable differences in the pathogenic potentials of different IgG subclasses: (1) the IgG2a and IgG2b subclasses of anti-red blood cell (RBC) autoantibodies are the most pathogenic and efficiently activate two classes of activating IgG Fc receptors (FcgammaRIII and FcgammaRIV) and complement; (2) the IgG3 subclass is less pathogenic and activate only complement; and (3) the IgG1 subclass is the least pathogenic and interact only with FcgammaRIII. In addition, because of the unique property of IgG3 to form self-associating complexes and generate cryoglobulins, this subclass of rheumatoid factor and anti-DNA autoantibodies became highly pathogenic and induced lupus-like nephritis and/or vasculitis. Since the switch to IgG2a and IgG3 is promoted by Th1 cytokine interferon gamma, these results strongly suggest that Th1 autoimmune responses could be critically involved in the generation of more pathogenic autoantibodies in systemic lupus erythematosus. This finding is consistent with the observation that the progression of murine lupus nephritis is correlated with the relative dominance of Th1 autoimmune responses. Finally, the analysis of IgG glycosylation pattern revealed that more sialylated IgG autoantibodies remained poorly pathogenic because of limited Fc-associated effector functions and loss of cryoglobulin activity. This suggests that the terminal sialylation of the oligosaccharide side chains of IgG could be a significant factor determining the pathogenic potential of autoantibodies. Our results thus underline the importance of subpopulations of autoantibodies, induced by the help of Th1 cells, in the pathogenesis of autoantibody-mediated cellular and tissue injuries.

Animals↗

Glutamic acid decarboxylase and IA-2 autoantibodies in type 1 diabetes: comparing sample substrates for autoantibody determinations.

Large-scale programs designed to assess risk for type 1 diabetes through serologic assessment of autoantibodies to recombinant beta-cell autoantigens are hampered by several limitations, including the methods for sample collection and assay performance, as well as the volume required for autoantibody determinations. The present study was designed to develop a low sample-volume, primary screening method for autoantibody detection of high specificity and sensitivity, and to determine the feasibility of dried blood spots collected on filter paper in serving as vehicles for such determinations. Autoantibodies to glutamic acid decarboxylase (GAD) and ICA512bdc (IA-2), both individually and in combination, were determined in persons with type 1 diabetes, healthy controls, or individuals with other autoimmune disorders. Autoantibody results for serum, plasma, and dried blood spots were compared. GAD, IA-2, and combined GAD/IA-2 autoantibodies were concordant in their measurement from minimal volumes of serum, plasma, and whole blood extracted from dried filter paper. The autoantibody levels from the dried blood spots were, however, lower than corresponding serum samples, and, as currently designed, failed to detect low-titer autoantibodies. Despite this limitation, screening for diabetes risk can be performed using small volumes of whole blood, serum, or plasma collected onto filter paper. These methodological improvements should simplify matters, reduce costs, and increase the efficacy of screening programs for type 1 diabetes. Further development of better substrates/methods for blood-specimen collection seems necessary to exploit the full potential of this and other autoantibody measurement strategies for screening large populations.

Journal Article↗

Experimental erythrocyte autoantibodies. V. Induction and suppression of red blood cell autoantibodies in mice injected with rat bromelain-treated red blood cells.

Mice injected with rat red blood cells (RBC), or rat bromelain-treated (brom) RBC, produce RBC autoantibodies and suppressor cells that specifically inhibit the autoimmune response without inhibiting the net production of antibodies against rat RBC. It has been investigated whether suppressor cells induced by injections of rat RBC are effective in preventing autoantibody production induced by rat brom RBC and vice versa. Autoantibodies were induced in C3H mice by weekly ip injections, each 0.2 ml, of a 6% suspension of rat RBC or rat brom RBC. Autoantibody production was assayed using Coombs' test. Suppressor cells were present in the spleens of mice positive in Coombs' tests and were shown by intravenous injections of 40 X 10(6) viable cells per mouse into untreated syngeneic mice 18 hr before the first injection of rat RBC or rat brom RBC. Autoantibodies eluted from mice positive in Coombs' tests after injections of rat RBC or brom RBC were absorbed by either type of rat RBC but not by RBC from sheep. This suggests that rat RBC and rat brom RBC display antigens that are similar, if not identical, to autoantigens on the mouse RBC. Spleen cells from mice injected with rat RBC suppressed autoantibodies induced by both rat RBC and rat brom RBC. In contrast, spleen cells from mice injected with rat brom RBC suppressed autoantibodies induced by rat brom RBC but not those induced by unmodified rat RBC. This differential suppression may be due to the removal from rat RBC, by bromelain, of a suppressor site and/or autoantigens of some specificities. Thus rat brom RBC may not induce the total range of specificities of autoantibodies, and of suppressor cells, induced by rat RBC.

Animals↗

Recombinant human natural autoantibodies against GPIIb/IIIa inhibit binding of autoantibodies from patients with AITP.

Autoimmune thrombocytopenic purpura (AITP) is caused by autoantibodies predominantly against platelet membrane glycoproteins (GP) IIb/IIIa and GPIb/IX. Naturally occurring autoantibodies have been described against a variety of autoantigens; it has been suggested that perturbation of their regulation may be associated with autoimmune diseases. Using a combinatorial Fab phagemid library from an individual immunized with human RhD+ red blood cells, we evaluated the presence of natural anti-GPIIb/IIIa autoantibodies as well as their relation to AITP-associated anti-GPIIb/IIIa autoantibodies. Selection on native GPIIb/IIIa and characterization of positive clones by inhibition studies against murine monoclonal anti-GPIIb/IIIa antibodies and by DNA analysis revealed the presence of two distinct recombinant anti-GPIIb/IIIa autoantibodies, which partially inhibited binding of affinity-purified platelet-associated autoantibodies from 8/12 AITP patients. Our results demonstrated that GPIIb/IIIa-specific Fab directed against conformational epitopes within the GPIIb/IIIa complex may be cloned from the genome of an individual immunized with RhD+ red blood cells, who was not affected by AITP. The partial inhibition of binding of platelet-associated autoantibodies from AITP patients to GPIIb/IIIa by the recombinant anti-GPIIb/IIIa phage clones suggests recognition of closely related antigenic epitopes. These phage clones may represent down-regulated, potentially pathological autoantibodies and could be used as new tools for investigation of AITP.

Amino Acid Sequence↗

Human monoclonal autoantibodies to B-cell epitopes outside the thyroid peroxidase autoantibody immunodominant region.

Human autoantibodies to thyroid peroxidase (TPO) interact with a restricted or immunodominant region (IDR) on intact TPO. However, a smaller proportion of polyclonal serum TPO autoantibodies bind outside this region. To isolate monoclonal nonimmunodominant region (non-IDR) TPO autoantibodies, we screened a thyroid-derived immunoglobulin gene phage display library while "epitope masking" the TPO IDR with four human TPO monoclonal autoantibodies that define the IDR. Among 31 non-IDR autoantibodies obtained (expressed as Fab), 8 representatives were analyzed further based on their restriction digestion profiles. All are encoded by almost identical H chains (VH3 family), with extremely long D regions, paired with three different types of light chains. In contrast, IDR TPO Fab from the same patient utilize seven different heavy chains (VH1 and VH5 families) paired nonpromiscuously with different light chains. Use of VH5 genes has not been reported previously for TPO autoantibodies. Both non-IDR and IDR Fab bind specifically to TPO and not to other proteins. The non-IDR Fab affinities for TPO are moderately high (Kd 1-2 x 10(-9) M), somewhat lower than those for most IDR Fab (Kd 1-4 x 10(-10) M). The epitopes of the three types of non-IDR Fab overlap with each other, indicating a major role for their heavy chain in TPO binding. Most importantly, the epitopes of non-IDR Fab are recognized by patients' serum autoantibodies. In summary, we provide the first insight into the immunoglobulin genes, affinities and epitopes of human monoclonal autoantibodies that bind outside the TPO-immunodominant region.

Amino Acid Sequence↗

Comparison between autoantibodies arising during Trypanosoma cruzi infection in mice and natural autoantibodies.

The autoantibodies induced in (C57BL/6 x BALB/c)F1 mice during Trypanosoma cruzi (CL strain) infection were analyzed and compared with natural autoantibodies present in healthy mice. Mice were killed at intervals after infection and their sera were tested by enzyme immunoassay against a panel of self- and non-self-Ag: actin, myoglobin, myosin, tubulin, DNA, and TNP-OVA. The level of IgM and IgG autoantibodies against all Ag started to increase from day 15 until 6 wk after the parasite infection. The high level of all autoantibodies persisted 3 mo postinfection, and 1 yr later, half of the mice still had elevated levels of IgM and IgG autoantibodies, particularly antitubulin IgG antibodies. IgM and IgG were isolated from pools of normal and infected mouse sera and their binding capacity to all Ag was compared. The titers of infected mouse sera were increased and the slopes of both IgM and IgG binding curves of autoantibodies to actin, myosin, and tubulin were greater than those of control mouse sera, indicating higher affinities. The average dissociation constant of the IgG2a autoantibody to mouse tubulin was 5 times lower than that of natural antitubulin IgG2a antibodies. Furthermore, absorption of the IgG from infected mouse sera onto a tubulin immunoadsorbent removed half the reactivity with tubulin and also with myosin, actin and parasite extracts. The eluted antibodies bound the same Ag. When IgG were further analyzed by Western blot on proteolytic fragments of tubulin, we found that antibodies from both groups bound to the same broad spectrum of polypeptide bands. However, additional fragments were recognized by antibodies from infected mice. All these results indicate that the autoantibodies naturally present in mice are significantly affected after infection with T. cruzi, in quantity as well as in specificity and affinity.

Animals↗

The presence of autoantibodies specific for NZB serum factors in adult NZB mice and the establishment of monoclonal autoantibodies against these humoral factors.

Humoral factors in serum of young NZB mice enhance maturation of B-lymphocyte precursors in vitro. A blot ELISA assay identified autoantibodies against the serum factors. NZB-SFs (designated NZB-SF alpha, pI 3.5-4.0, and NZB-SF beta, pI 7.8) were purified by sequential steps. Both had a molecular weight (MW) of approximately 23,000 in SDS-PAGE. NZB mice develop autoantibodies against NZB-SFs by 2 months of age; titers increased progressively with age. Non-autoimmune-prone mice did not produce autoantibodies against NZB-SFs. We then developed two hybridoma clones, IIC1C1 and IIC1M4, which produce monoclonal autoantibodies against NZB-SF alpha and NZB-SF beta, respectively. Both IgM autoantibodies could be affinity purified with a column of CNBr-Sepharose 4B gel conjugated with anti-mouse IgM antibody. Neither IIC1C1 nor IIC1M4 abolished bioactivity of recombinant mouse IL-1 alpha, human IL-1, mouse, rat, or human IL-2, mouse IL-3, or colony-stimulating factor. Neither antibody reacted to recombinant mouse IL-1 alpha, IL-4, TNF alpha, or IFN gamma in blot ELISA assays. Monoclonal autoantibodies IIC1C1 and IIC1M4 were used to purify NZB-SFs. SDS-PAGE of the affinity-purified NZB-SFs revealed bands of 23 and 60 kDa, and proteins extracted from the bands were reactive to our monoclonal autoantibodies.

Animals↗

Autoantigenic determinants on human thyroglobulin. II. Determinants recognized by autoantibodies from patients with chronic autoimmune thyroiditis compared to autoantibodies from healthy subjects.

Using a panel of 20 well-characterized mouse monoclonal antibodies (mAbs) to native human thyroglobulin (Tg), the fine specificities of autoantibody responses in human autoimmune thyroiditis patients were compared to naturally occurring autoantibodies from healthy individuals. The antigenic determinants recognized by the human autoantibodies were assessed using competitive binding assays in which murine mAbs were inhibited by human autoantibodies. All determinants of human Tg recognized by the mouse were also responded to by the human subjects. Autoantibodies from adult and juvenile patients with chronic lymphocytic thyroiditis recognized principally 10 of 19 determinants defined by the panel of murine mAbs. The mAbs which define these 10 determinants do not react with Tg from seven other mammalian species; therefore, autoantibody responses in individuals with thyroiditis are directed primarily to species specific determinants of human Tg. These same determinants on human Tg were the principal ones recognized by the mouse following immunization. Particular patterns of fine specificities were not inherited from parents by probands or their siblings, even if identical twins. Naturally occurring Tg autoantibodies from healthy subjects recognized mainly thyroxine-containing cross-reactive determinants.

Adolescent↗