Effect of anti-insulin antibodies on glycemic control in insulin treated diabetic patients

In order to examine the effect of anti-insulin antibodies on serum insulin concentration and glycemic control, sera from 49 insulin-treated diabetic patients (20 males and 29 females) were examined for their titer of anti-insulin antibodies, and concentrations of total insulin (TIRI), free insulin (FIRI) and hemoglobin A1c. Titer of anti-insulin antibodies correlated only with TIRI (r = 0.72, p less than 0.001) and did not correlate with duration of insulin treatment, FIRI concentration, daily dose of insulin, or HbA1c concentration. These results indicate that elevated titer of anti-insulin antibodies in patients under insulin therapy, increases total serum insulin concentration but does not affect serum free insulin level, and has little effect, if any, on glycemic control and the required daily dose of insulin.

Production of idiotypic and anti-idiotypic antibodies by BALB/c mice in response to immunizations with glucagon, vasopressin, or insulin: supporting evidence for the network concept

After immunizations with glucagon or vasopressin, either conjugated to keyhole limpet hemocyanin or adsorbed to polyvinylpyrrolidone, both anti-hormone and anti-receptor activities were detectable in the serum of injected mice. Anti-hormone activity was identified by ELISA techniques; anti-receptor activity, by determining the ability of serum samples to compete with labeled hormone for glucagon or vasopressin receptors on rat liver plasma membranes. Anti-receptor activity appeared only after the peak anti-hormone response to each immunogen had been established, and required intensive immunizations (six to nine monthly injections). The presence of anti-idiotypic antibodies in serum samples containing glucagon or vasopressin anti-receptor activity was confirmed by demonstrating selective binding of such samples to corresponding rabbit idiotypic antibodies. Serum from mice immunized with insulin also contained anti-hormone activity, as determined by ELISA, and anti-receptor activity, as determined by noting insulin-mimicking properties in stimulating glucose transport in rat adipocytes. The anti-insulin receptor activity developed after only one boost with the hormone. These results are consistent with Jerne's network hypothesis in that the glucagon, vasopressin, and insulin anti-receptor activity may be attributed to antibodies produced in mice as part of an idiotypic-anti-idiotypic network.

Antibodies to the alpha-subunit of insulin receptor from eggs of immunized hens

Simple methods for the generation, purification, and assay of antibodies to the alpha-subunit of insulin receptor from eggs of immunized hens have been described. Chicken antibodies against the alpha-subunit inhibit insulin binding to the receptor and stimulate glucose oxidation as well as autophosphorylation of the beta-subunit. Thus the properties of chicken antibodies are very similar to those of antibodies found in human autoimmune diseases and different from rabbit antibodies obtained against the same antigen.

Insulin antibodies in patients receiving penicillamine

In a patient receiving penicillamine for treatment of rheumatoid arthritis, antibodies to insulin developed, which resulted in symptomatic hypoglycemia. When 30 additional patients receiving penicillamine were screened, another patient was discovered to have antibodies to insulin. The level of antibody fell sharply in both patients after penicillamine was discontinued. This particular immunologic reaction to penicillamine has not been reported previously.

Effect of insulin antibodies on insulin pharmacokinetics and glucose utilization in insulin-dependent diabetic patients

To determine the impact of insulin-binding antibodies on total (TIRI) and free insulin (FIRI) as well as on insulin sensitivity, 10 insulin-dependent diabetic patients (IDDM) with poststimulatory C-peptide less than 100 pmol/L and an insulin binding capacity (IBC) between less than 1 and 294 micrograms/L serum were studied during and after a 1-h nonprimed, constant-rate insulin infusion (study 1: 0.057 U/kg body wt, study 2: 0.286 U/kg body wt). Euglycemia was maintained by variable glucose infusion. Control studies were performed in 5 healthy subjects. Basal TIRI (mU/L) was lowest in healthy subjects (16 +/- 1 [SE]) and elevated in diabetic patients (IBC less than 25 micrograms/L: 72 +/- 11, IBC greater than 25 micrograms/L: 1772 +/- 842), whereas serum concentrations of FIRI were considerably smaller but still two- to threefold greater (P less than 0.01) in the patients than in healthy subjects (13 +/- 1). After intravenous (i.v.) insulin administration, almost identical increments in serum TIRI were seen in healthy subjects and in diabetic patients with low IBC (less than 25 micrograms/L), whereas those with high IBC (greater than 25 micrograms/L) had a heterogeneous response.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin-specific tolerance induction. II. Tolerant helper T cells can be rescued by insulin complexed to Brucella abortus

Murine antibody responses to heterologous insulins are under H-2-linked immune response (Ir) gene control. We previously demonstrated that the immune response to insulin in Freund's complete adjuvant (CFA) can be specifically inhibited by prior injection of soluble insulin i.v. Unresponsiveness requires at least 4 days after i.v. injection to develop, and once induced, it lasts 4 wk or more. Unresponsiveness is caused by T cell, but not B cell, tolerance; furthermore, we have been unable to demonstrate any role for suppressor T cells in this unresponsiveness. The following experiments examine the nature of the T cell tolerance induced by i.v. injection of insulin, and the data suggest that helper T cells were not clonally deleted by this procedure. The functional activity of the tolerized T cells can be rescued by stimulation with insulin covalently complexed to the type 1 T-independent (TI-1) antigen, Brucella abortus. This observation suggests that tolerance induced by soluble insulin is due to clonal anergy rather than clonal deletion of helper T cells; thus, this system could provide a model for determining the cellular events involved in tolerance induction and reversal in helper T cells.

IgE antibody studies in a case of generalized allergic reaction to human insulin

A patient developed a generalized reaction to purified bovine, purified porcine and human insulin. High levels of IgE antibody to bovine, porcine, human emp and human crb insulin were demonstrated. These fell dramatically following desensitization with human crb insulin. All four types of insulin gave superimposable RAST inhibition curves indicating a common allergen determinant.

The suppression of insulin-specific immune responses by the administration of insulin-derivatized syngeneic cells and soluble lysates from these cells

The results of this study demonstrated that the i.v. administration of insulin, in the form of a conjugate with either syngeneic spleen cells (SC) or peritoneal exudate cells (PEC), markedly reduced the capacity of recipient mice to develop insulin-specific immune responses, as manifested by diminished in vivo IgE antibody production and by depressed in vitro, lymph node cell proliferation responses, respectively. Furthermore, it was shown that i.v. injection of insulin-PEC conjugates induced the activation of suppressor cells that had the capacity to downregulate insulin-specific IgG plaque-forming cell (PFC) responses. Finally, it was also determined that freezing and thawing of the insulin-PEC conjugates resulted in the release of a soluble tolerogenic molecule and/or membrane preparation that could also markedly depress insulin-specific IgG antibody production.

Regulatory mechanisms in immune responses to heterologous insulins. II. Suppressor T cell activation associated with nonresponsiveness in H-2b mice

Murine antibody responses to insulins are controlled by MHC-linked Ir genes. Although mice of the H-2b haplotype do not make antibody in response to pork insulin, we demonstrate in this communication that immunization with pork insulin stimulates radioresistant, Lyt-1+2- helper T cells that are capable of stimulating secondary antibody responses to pork insulin in vitro, but that this activity is masked by radiosensitive, Lyt-1-2+, I-J+ suppressor T cells. The suppressor T cells, present after immunization with pork insulin but not beef insulin, suppress the secondary response to pork but not beef insulin. The amino acid sequences of pork and beef insulins differ only at the A-chain loop; thus, pork insulin-specific suppressor T cells appear to recognize the A-chain loop determinant of pork insulin. The amino acid sequences of mouse and pork insulin are identical in the A-chain loop, which suggests that these suppressor T cells may be self-reactive. If this interpretation is correct, these suppressor T cells could be involved in the maintenance of self-tolerance to insulin. Nevertheless, these data clearly demonstrate that genetically determined nonresponsiveness in H-2b mice is conferred by activation of dominant, insulin-specific suppressor T cells (Ts), rather than by a defect in the stimulation of insulin-specific helper T cells (Th).

[Hormonal function of islands of Langerhans in diabetes mellitus]

Some hormonal characteristics were examined in 23 patients with diabetes mellitus. Of these, 7 patients had an insulin-dependent and 19 an insulin-independent disease pattern. It was demonstrated that after treatment the level of IRI and c-peptide remained within normal. The levels of glucagon and somatostatin were considerably elevated and did not show any noticeable decrease after treatment. Both groups manifested an increased number of antibodies against insulin, with that number remaining virtually unchanged after treatment.

Acidic "peptidophospholipids", a new class of hapten-bearing cell surface modifying reagents

Covalent coupling of glutamyl-glutamic acid to the amino group of ether-phosphatidylethanolamine (EPE) yields an acidic "peptidophospholipid" (Glu2-EPE) which is water-soluble above pH 7.0 and stable to phospholipase A. The terminal amino group of Glu2-EPE is free for coupling with amino-reactive determinants. We describe the synthesis of various hapten-substituted peptidophospholipids as well as of an intermediate compound, coupled with the heterobifunctional reagent 3-(2'-pyridyl)-dithiopropionic acid N-hydroxysuccinimide ester. The latter derivative allows binding to sulfhydryl-containing molecules, e.g. peptides or proteins. So far, beef and pig insulin as well as trinitrophenyl-substituted ribonuclease A have thus been linked to Glu2-EPE. All derivatives of Glu2-EPE are water-soluble at physiological pH and readily adsorb to cell surfaces from aq. solution. Binding to cells is fast, stable and "non-toxic" over a wide range of concns. The adsorbed determinants are accessible to specific antibodies and facilitate complement-mediated cell lysis. Glu2-EPE thus appears to be a universal carrier molecule for fast, simple and mild modification of cells with foreign determinants, e.g. for Jerne plaque assays.

HLA phenotype and insulin antibody production

HLA phenotypes have been determined in 79 patients as part of a prospective study of factors governing the immune response to injected insulin. IgG insulin antibody levels 6 months after starting treatment with bovine insulin were significantly higher in patients bearing HLA-DR7 and this in conjunction with the lack of a similar pattern in the IgG response to Helix pomatia haemocyanin, suggests the presence of an immune response gene for insulin. The hyporesponsiveness of HLA-B8/DR3/C4AQ0 positive individuals is more likely to reflect a non-specific abnormality of immunity.

Immunological properties and biological effectiveness of insulin analogues substituted at position B30

The aim of this investigation was to assess the immunological properties of several insulin analogues by examining both their antigenic and immunogenic behaviour. In addition, the hypoglycaemic activity was also determined and compared with values obtained with natural insulin. The modified insulin preparations were of porcine and bovine origin. All analogues had in common the fact that the alanine B30 had been exchanged by either leucine, threonine, tyrosine, phenylalanine or glycine. The blood glucose-lowering activity was determined in rabbits and dogs, while the stimulation of antibody development was studied in three different animal species; pigs, dogs and rabbits. The antigenic properties of analogues were evaluated in vitro by measuring their binding capacity to pre-formed antibodies. In all cases the blood glucose lowering activity of the analogues was comparable to that of the respective natural insulin. There were remarkable differences in the binding capacity to pre-formed antibodies, with bovine Leu-B30 insulin competing only to 73% with the natural insulin tracer. With regard to antibody development, the analogues behaved similarly to the original hormones. These results show that there is little correlation between the antigenic make-up of the insulin molecule and its ability to provoke antibody stimulation.

Immunogenicity of monocomponent human and porcine insulin in newly diagnosed type 1 (insulin-dependent) diabetic children

The aim of the present study was to compare the immunogenicity of monocomponent human insulin with that of monocomponent porcine insulin in newly diagnosed Type 1 (insulin-dependent) diabetic children. One hundred and thirty-five patients at diagnosis of diabetes (age 1-18 years, mean age 9.3 years) were randomly allocated to treatment with either Monotard MC + Actrapid MC or Monotard HM + Actrapid HM in a double-blind trial conducted in Sweden, Finland, Norway and Denmark. The human and porcine insulin groups were identical at diagnosis with respect to age, sex and measures of metabolic control. At all times the mean insulin antibody levels and the percentage of antibody-positive patients were lower in the human group compared with the porcine group. At 3 and 12 months, the insulin antibody values were significantly lower in the human group than in the porcine group (p less than 0.05, Wilcoxon's rank sum test). At 12 months, antibody values in the human group ranged from 0 to 1.2 U/l (mean 0.14 U/l) and in the porcine insulin group from 0-5.2 U/l (mean 0.63 U/l). It is therefore concluded that human monocomponent insulin has a lower immunogenicity than porcine insulin of the same purity in newly diagnosed diabetic children during the first year of insulin treatment.

Thyrogastric autoimmunity and MHC associated alleles at the C4 locus in patients with type 1 (insulin-dependent) diabetes

HLA antigens, complement allotypes, insulin antibodies and thyrogastric autoantibodies were determined in 69 patients with Type 1 (insulin-dependent) diabetes defined by a tendency to ketosis, non-obesity and insulin requirement within 2 years of diagnosis. Analysis of HLA and C4 allotypes suggested that Type 1 diabetes was associated with only certain DR3- and DR4-containing supratypes. Low antibody response to insulin was associated with all HLA-DR3, being present in 89% of those with DR3 compared with 48% of those without. Thyrogastric autoantibodies were associated with a null allele at the C4A locus, usually with HLA-B8-C4AQO-C4B1-BfS-DR3. These results indicate that, unlike Type 1 diabetes, low insulin antibody response was associated with all HLA-DR3. Thyrogastric autoantibodies, on the other hand, were associated with a null allele at the C4A locus. It is probable that while interaction between certain HLA-DR3 and DR4-containing supratypes is important in conferring susceptibility to Type 1 diabetes, other manifestations of autoimmunity are associated with supratypes containing C4AQ0, and in particular the diabetogenic supratype HLA-B8-C4AQ0-C4B1-BfS-DR3.

Further evidence against random polyclonal antibody formation in mice with lupus-like graft-vs-host disease

The pathologic symptoms in F1 mice with chronic graft-vs-host disease (GVHD) (GVH F1) strongly resemble those of systemic lupus erythematosus (SLE). Mice with SLE-like GVHD do not produce antibodies to a number of non-self and self antigens. This finding is inconsistent with the widely accepted view that the (auto)-antibody formation in SLE is polyclonal in the sense that B cells are triggered at random, i.e., irrespective of their specificity. In the present study, therefore, we performed a systematic study of the kinetics of total IgM- and IgG-secreting splenic B cells and tested their specificities. The total IgM-secreting B cell population was increased only in the first week after the initiation of SLE-like GVHD; it seemed to reflect a random, but self-limited, polyclonal B cell stimulation. In contrast, the total number of IgG-secreting cells in the GVH F1 mice was increased to a much higher extent than that of the IgM-secreting cells and remained increased. At no time during GVHD was there an increase in the number of plaque-forming cells (PFC) spontaneously secreting IgG antibodies to non-self antigens. The GVH reaction (GVHR) did, however, lead to the appearance of PFC that secreted IgG antibodies to DNA. Similarly, the GVH F1 mice showed high serum titers of antibodies to self antigens characteristic of SLE and to endogenous viruses, but during the entire observation period they failed to develop serum antibodies to non-self antigens and insulin. Hence, the enhanced production of Ig, especially that of IgG, that occurs in SLE-like GVHD is not a random process, because it requires the presence of antigen, or signal 1. The data support our hypothesis that only certain kinds of self antigen, such as DNA and cell membrane epitopes, can cross-link the Ig receptors on the corresponding B cells and thus provide an adequate signal 1. Given the increase in help, or signal 2, in chronic GVHD, only the B cell clones that simultaneously receive an adequate signal 1 seem to be driven into clonal proliferation and IgG secretion.

[Preliminary note on anti-insulin antibody formation in diabetics treated with porcine insulin]

In the present study, we have tested the sera of sixty five diabetic patients treated with insulin, researching the action of some physiologic and therapeutic factors (sex, age, insulin dose and time of treatment), to production of anti-insulin antibodies. Our results have shown that an important percentage of diabetic patients treated by porcine insulin produce antibodies: 72% of studied patients, concerning chiefly all the women and patients under-fourty years old. However our results have not pointed out any relation between the administered insulin dose versus the anti-insulin antibodies production, in spite of the early production of these antibodies in a great part of the patients.

Insulin-specific tolerance induction. I. Abrogation of helper T cell activity is controlled by H-2-linked Ir genes

Murine antibody responses to heterologous insulins are under H-2-linked immune response (Ir) gene control. We have found that the immune response to insulin in adjuvant can be inhibited by prior i.v. injection of soluble insulin. The effect of i.v. injection of insulin is antigen-specific and dose-dependent and requires the same doses of insulin that are immunogenic if administered with adjuvant. In addition, the inhibitory effect of soluble insulin is dependent upon the route of injection; if soluble insulin is injected i.p., the subsequent response to insulin in adjuvant is augmented rather than inhibited. Unresponsiveness requires at least 4 days after i.v. injection to develop and once induced, it is maintained for 4 wk or more. Unresponsiveness is caused by T cell, but not B cell, tolerance, and we have been unable to demonstrate any role for suppressor T cells in this unresponsiveness. More importantly, analysis of the ability of numerous insulin variants to induce unresponsiveness in several H-2k and H-2b strains of mice has demonstrated that only the variants that were immunogenic in a given strain when administered with adjuvant were able to cause tolerance. This report is, to our knowledge, the first describing that induction of helper T cell tolerance, like the induction of immunity, is controlled by H-2-linked Ir genes.

Effects of antithyroid drugs on lymphocyte proliferative responses to lectins: relationship between insulin autoimmune syndrome and methimazole

Using peripheral blood lymphocytes from 8 healthy individuals and 5 patients with untreated Graves' disease, direct effects of methimazole (MMI) and propylthiouracil (PTU) on lectin-induced lymphocyte proliferative response were studied. Lymphocytes were cultured for 72 hr in the presence of lectins and antithyroid drugs. Lymphocyte DNA synthesis was counted by incorporation of 3H-thymidine. MMI at 1,000 microM enhanced lectin-induced lymphoproliferation of peripheral blood lymphocytes from both patients with Graves' disease and healthy individuals, at every point of culture time, while PTU showed a tendency toward suppression. These results suggest that this lympho-stimulation by MMI may be a causative factor related to insulin autoimmune syndrome, as deduced from the clinical reports that insulin autoimmune syndrome is, sometimes, found in patients with Graves' disease treated with MMI. This lympho-stimulation was evident regardless of the time of MMI addition, thus indicating that MMI is, by its action, a lymphoid stimulator and may lead to the insulin autoimmune syndrome in predisposed subjects with underlying Graves' disease.

In vitro immunization for the production of antigen-specific lymphocyte hybridomas

Antigen-specific lymphocyte hybridomas have been produced by a simple in vitro immunization procedure. Non-immune spleen cells have been activated in vitro, and the B-cell blasts have subsequently been used for somatic cell hybridization. Hybrids secreting monoclonal antibodies to human myoglobin, pig insulin, and benzo(a)pyrene were obtained with splenocytes that had been immunized 5 days in culture before the hybridization. The frequency of specific hybridomas was the same as or higher than that of hybridomas produced from in vivo-immunized cells, showing the versatility of the procedure when making monoclonal antibodies to haptens and proteins with a conserved structure or to small amounts of antigen. Monoclonal antibodies of both IgG and IgM isotypes could be isolated.