Insulin-binding Antibodies Research Articles

Relationship of glycosylated haemoglobin to C-peptide secretory status and antibody binding of insulin in insulin-dependent diabetes.

Diabetic control, assessed by measuring the concentration in venous blood of total glycosylated haemoglobin (HbA1), endogenous insulin secretion, as estimated by the C-peptide response (delta C-P) to intravenous glucagon, and serum beef insulin antibody binding were measured in 50 juvenile onset insulin dependent diabetics (IDDM) receiving a single daily injection of soluble and protamine zinc insulin. The delta C-P correlated inversely with duration of diabetes (tau = -0.27, p less than 0.01) and daily insulin requirement (tau = -0.22, p less than 0.05) in the 50 IDDM studied of whom 28 exhibited a measurable delta C-P. In C-peptide nonresponders, but not in the C-peptide responders, and inverse regression (t = 2.19, p less than 0.05) was observed between beef insulin antibody and HbA1. In the 25 IDDM having the lowest insulin antibody binding, and inverse correlation (tau = 0.36, p less than 0.02) was observed between delta CP and HbA1, which was not found (tau = 0.05) in the remaining 25 IDDM who had the highest insulin antibody binding. These findings suggest that, in the absence of endogenous insulin secretion, diabetic control in IDDM receiving a single daily injection of conventional beef insulin is better in patients with high beef insulin antibody binding. Conversely, in patients with low beef insulin antibody binding, diabetic control appears to be better in those with persisting endogenous insulin secretion.

Differential Response to Infusions of Highly Purified and Conventional Bovine and Porcine Insulins

The glucose clamp technique allows quantification of tissue sensitivity to insulin without modulation by the effects of hypoglycemia. The amount of glucose infused to maintain euglycemia during an insulin infusion gives a direct measure of tissue sensitivity. We have used this technique to compare the metabolic effects of highly purified porcine, highly purified bovine, and conventional insulins in diabetic subjects: (A) a group normally taking conventional bovine insulin, and (B) diabetics who had originally been treated with conventional bovine insulin and had changed to highly purified porcine insulin. Subjects were studied while attached to Biostator with blood glucose values clamped at the basal level during a 2-h insulin infusion (0.01 U/kg/h). both groups of diabetics received significantly more glucose in the first hour of the monocomponent porcine insulin infusion than during the same period either of conventional or highly purified bovine insulin infusion. Highly purified porcine insulin infusion was also associated with a more rapid fall in blood ketone body concentrations. Highly purified porcine insulin infusion was accompanied by a greater and earlier increase in free insulin concentrations. All diabetics had antibodies to insulin but no differential antibody binding of beef and pork insulin was found in the two groups of patients. Thus, use of highly purified porcine insulin is associated with a more rapid onset of action and a greater initial increment in free insulin values.

Transplacental passage of insulin complexed to antibody.

The passage of plasma proteins across the placental barrier in humans is known to be highly selective. Thus, free maternal insulin has been reported not to cross the normal maternofetal barrier, although insulin-binding antibodies have been detected in newborn infants whose diabetic mothers received insulin therapy. In this report we demonstrate, with the use of a human antiserum that permits distinction between human and animal insulins, that insulin in the cord blood of each of two neonates of insulin-treated diabetic mothers was, in part, animal insulin. The higher the antibody titer of the mother the greater was the total insulin in the cord plasma and the greater was the fraction that was animal insulin. In case 1 cord plasma insulin was 0.7 unit/liter, of which 10% was animal insulin; in case 2 cord plasma insulin was 3.5 units/liter, of which 25% was animal insulin. The demonstration that antigen restricted from transplacental passage can be transferred while complexed to antibody raises the question whether such fetal exposure would induce partial or total immunologic unresponsiveness subsequently if the fetus were rechallenged with the same antigen.

Insulin, pancreatic polypeptide, and glucagon antibodies in insulin-dependent diabetes mellitus.

To assess the possible value of the use of high-purity pork insulin (HPPI) in the United States, the serum insulin (I), pancreatic polypeptide (PP), glucagon (G), and somatostatin (SRIF) antibody binding characteristics have been determined in 90 conventional insulin-treated diabetic subjects and related to their degree of metabolic control, as assessed by glycosylated hemoglobin (HbA1) concentration. All diabetic subjects had antibodies to insulin, but there was no relationship between any of the antibody binding characteristics and HbA1 level: 47% possessed PP antibodies; mean +/- SEM HbA1 in these patients was 14.5 +/- 0.3%, identical to those without PP antibodies (14.5 +/- 0.4%); 10% had G binding antibodies with HbA1 levels of 14.6 +/- 0.8%, similar to those without G antibodies. No subject possessed SRIF antibodies. This lack of correlation between antibody characteristics and metabolic control makes it unlikely that, in the majority of patients, treatment with a less immunogenic insulin (HPPI) versus conventional insulin will result in improved diabetic control.

Residual Pancreatic Beta-cell Function and Insulin Binding Antibody Formation in Juvenile-onset Diabetes Mellitus

Residual Pancreatic Beta-cell Function and Insulin Binding Antibody Formation in Juvenile-onset Diabetes Mellitus

Circulating insulin-binding antibodies.

Insulin was first used in the treatment of diabetic patients in 1921 and the first immunological problem associated with its use was reported in 1922 [1]; a patient developed anaphylaxis after the injection of a porcine, but not of a bovine insulin preparation. At that time insulin preparations were very impure and the antigen was probably a contaminating substance rather than insulin. In subsequent years a small number of patients were found to have developed insulin resistance after treatment with insulin [2]. In

Decrease of antibodies to insulin, proinsulin and contaminating hormones after changing treatment from conventional beef to purified pork insulin.

The sera of 30 patients who had been treated with conventional beef insulin were tested for binding of insulin and other pancreatic hormones. All showed antibody binding of insulin, 29 binding of proinsulin, 29 binding of pancreatic polypeptide, two binding of glucagon but none of the sera bound vasoactive intestinal peptide or somatostatin. After changing therapy to highly purified pork insulin the binding capacity of sera for insulin and the other hormones was monitored for up to 35 months and a steady fall was found in nearly all cases. In eight of the patients conventional beef insulin treatment was resumed: in one month binding of insulin and of the other hormones increased back to the initial levels. In eighteen subjects who had only received highly purified pork insulin low levels of insulin binding were found with no binding of proinsulin or other hormones. The amounts of proinsulin and contaminating hormones in highly purified pork insulin are so low that they are not immunogenic; conventional beef insulin not only contains immunogenic amounts of proinsulin and the contaminating hormones pancreatic polypeptide and glucagon but also is more immunogenic than purified pork insulin.

Determination of purity and identification of animal sources of insulin in various insulin preparations.

Prolonged administration of insulin leads to the formation of insulin-binding antibodies due to contaminant peptides and the animal source of the insulin. It follows that quantitation and identification of these factors are of significant importance in pharmaceutical insulin preparations. The assay and test procedures stipulated in the current pharmacopoeia of various countries, nevertheless, cannot determine either of these effects. In the present study, the content of impurities in insulin preparations was measured by polyacrylamide gel disc electrophoresis and the animal source of insulin identified by amino acid analysis. Assays of 17 commercial insulin preparations by these techniques revealed diversity in purity and animal sources of insulin. The present results suggest potential usefulness of these assay methods and advisability of their adoption not only by the manufacturers but also by the official pharmacopoeia as well.

Determination of Purity and Identification of Animal Sources of Insulin in Various Insulin Preparations

Prolonged administration of insulin leads to the formation of insulin-binding antibodies due to contaminant peptides and the animal source of the insulin. It follows that quantitation and identification of these factors are of significant importance in pharmaceutical insulin preparations. The assay and test procedures stipulated in the current pharmacopoeia of various countries, nevertheless, cannot determine either of these effects. In the present study, the content of impurities in insulin preparations was measured by polyacrylamide gel disc electrophoresis and the animal source of insulin identified by amino acid analysis. Assays of 17 commercial insulin preparations by these techniques revealed diversity in purity and animal sources of insulin. The present results suggest potential usefulness of these assay methods and advisability of their adoption not only by the manufacturers but also by the official pharmacopoeia as well.

Antibody binding of insulin in diabetic ketoacidosis.

This study investigates the effects of insulin antibody binding on free insulin levels measured in patients with acute diabetic ketoacidosis receiving insulin by constant infusion. In spite of antibody binding ranging from 10 to 90 per cent of the total circulating insulin, the steady state concentrations of free insulin were similar to those observed in individuals on identical infusion rates but without insulin-binding antibodies. However, the levels of free insulin in two patients were substantially lower than expected for the rate of insulin infusion, even though levels of bound insulin were not greatly elevated. An infusion rate of at least 4 U. per hour produced satisfactory rate of fall of plasma glucose, whereas lower dose regimens (2 U. per hour)--producing steady state free insulin concentrations ranging from 28 to 49 mU. per liter in different subjects--were unreliable in controlling the metabolic abnormalities of diabetic ketoacidosis.

Antibody binding of insulin in diabetic ketoacidosis

Antibody binding of insulin in diabetic ketoacidosis

H-2 Linked Ir Gene Control of Antibody Responses to Porcine Insulin

Abstract Cell-mediated and humoral immune responses to heterologous insulins in mice are controlled by H-2-linked, dominant, immune response (Ir) genes. For example, mice bearing the H-2d haplotype develop T cell proliferative responses and produce antibody after injection with porcine insulin, whereas mice bearing other H-2 haplotypes do not. Data presented in this communication demonstrate that homozygous and heterozygous H-2d mice produce insulin-binding antibodies when immunized with porcine insulin or proinsulin. Some (H-2b,k,s) insulin-nonresponder mice produce insulin-binding antibodies after injection of proinsulin, whereas other insulin-nonresponder strains (H-2q) do not. All strains, except homozygous H-2q mice, produce antibodies specific for proinsulin, suggesting that the response to porcine proinsulin is also controlled by H-2-linked Ir genes. More importantly, F1 hybrids between insulin-nonresponder C57BL/10 (H-2b) and DBA/1 (H-2q) produce no insulin-binding antibodies when injected with proinsulin, despite the fact that proinsulin-binding antibodies are produced by these mice.

Insulin-binding antibody: Reaction differences with bovine and porcine insulins

Insulin treated patients frequently develop insulin-binding antibody. Antisera from some patients, treated with bovine or bovine/porcine insulin mixtures, react differently with bovine and porcine insulin while for others there is no difference: when there is a difference there is greater avidity for bovine than porcine insulin. We studied antisera from 16 patients who had previously been treated with bovine insulin and then were changed to porcine insulin. Dissociation rate constants and association rates were measured with bovine and porcine insulin. Significant differences were found in association rates, which correlated well with binding at equilibrium (r=0.91), but not in dissociation rates. For 11 subjects who stayed on highly purified porcine insulin, long term reduction in insulin requirement correlated with the magnitude of the difference in antibody reaction to bovine and porcine insulin (r=0.74).

Congenital generalized lipodystrophy with insulin-resistant diabetes

Hyperglycemia, glucose intolerance, hyperinsulinemia and resistance to exogenous insulin were found in a 10-year-old Japanese boy diagnosed as having congenital generalized lipodystrophy. Studies on insulin receptors of circulating mononuclear leucocytes indicated that insulin-resistant diabetes combined with congenital generalized lipodystrophy may be due to disturbance of insulin binding to membrane receptors. No insulin-binding antibody or antibody that impairs insulin-receptor binding was found. Plasma glucagon showed an exaggerated response to L-arginine before treatment. After treatment with a controlled diet and an oral sulfonylurea (500 mg/day) for 4 weeks, there was improvement in the plasma glucagon response to L-arginine. Improvement in the hyperglycemia, hyperinsulinemia and acanthosis nigricans was also observed. On the other hand, on completion of a 7-day high-fat diet, a marked increase in serum free fatty acids, triglycerides and beta-lipoproteins was observed. The total plasma post-heparin lipolytic activity during the high fat diet was within the normal range. However, the level of protamine-inactivated activity was 3 times that of the control.

Studies on the Properties and Clinical Significance of Insulin Binding Antibodies

Studies on the Properties and Clinical Significance of Insulin Binding Antibodies

Factitious Hypoglycemia

In seven patients with factitious hypoglycemia due to the surreptitious injection of insulin, we made the diagnosis by measurements of plasma insulin and C-peptide immunoreactivity (in seven patients), facilitated by the finding of circulating insulin-binding antibodies (in two patients). The simultaneous demonstration of low plasma glucose, high immunoreactive insulin and suppressed C-peptide immunoreactivity represents a triad of results pathognomonic of exogenous insulin administration. Determination of plasma free C-peptide and free insulin permitted patients with high titers of insulin antibodies, including those with a history of insulin-treated diabetes, to be studied and diagnosed in a way similar to that in subjects who had no circulating insulin antibodies.

Studies on a Double Antibody Precipitation Method for the Determination of Insulin Binding Antibody and the Property of Insulin Binding Antibody

Studies on a Double Antibody Precipitation Method for the Determination of Insulin Binding Antibody and the Property of Insulin Binding Antibody

Renal wastage of insulin in children with diabetes mellitus.

In normal human beings the percentage of serum insulin excreted in the urine is constant over a wide range of values. The quantity of immunoreactive insulin found in the urine is believed to reflect the level of free insulin in the serum. Immunoreactive insulin was measured in the urine of nondiabetic children and diabetic children receiving exogenous insulin. Children with diabetes mellitus excreted greater amounts of immunoreactive insulin (18.5+/-8 muU./mg. creatinine) than did nondiabetic children (11.9+/-5 muU./mg. creatinine). This difference was statistically significant (p less than 0.0005). Children with "poor glycemic control" excreted a greater portion of their administered insulin dose than did those with "good control." The renal wastage of insulin correlated (r=0.94) with the duration of insulin treatment but not with the quantity administered. Antibody binding of serum insulin may explain in part these observations, but an acquired defect in the renal tubular reabsorption of insulin may also exist. Modifications in the management of diabetes that reduce the renal wastage of insulin may improve the metabolic stability of children with "poor diabetic control."

Insulin-binding antibodies in diabetic patients. Dynamic aspects of their formation.

Insulin-binding antibodies in serum of two groups of diabetics were followed up for a longer period of time. The first group had never been treated with exogenous insulin and showed a low antibody titer, with negligible changes in their level and diminishing of antibody production during ageing. Patients who had received insulin presented some differences: strong dependence of antibody titer on insulin dose; the very high doses, however, as well as a long period of treatment with insulin were accompanied with lowering of antibody concentration.

THE IMMUNOGENIC PROPERTIES OF HIGHLY PURIFIED INSULIN PREPARATIONS. THE CLINICAL IMPORTANCE OF INSULIN-BINDING ANTIBODIES

Twenty-four diabetic patients were treated with porcine protamine-insulin (NPH-insulin) containing 7-13 mmol proinsulin per mol insulin and 27 diabetic patients were treated with porcine protamine-insuline (HP-insulin) containing 0.36 mmol proinsulin per mol insulin. 75% of the patients treated with NPH-insulin and 15% of the patients treated with HP-insulin formed detectable insulin-binding antibodies. The difference in the antibody titre in the two groups was significant. As a group, patients treated with HP-insulin did not have significant rise in the plasma insulin-binding capacity when compared to pre-treated values. When comparing patients with antibodies and patients without detectable antibodies no difference in the degree of regulation could be demonstrated between the two groups. Young patients with antibodies had a higher insulin requirement per kg per day than patients without detectable antibodies. Among patients in remission those without detectable antibodies had a longer remission period than those with antibodies. Apart from the difference in antibody formation and hence a different distribution in the groups compared, the patients treated with NPH-insulin and HP-insulin did not differ with regard to the degree of regulation, the insulin requirement or the duration of the remission period.