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Biomedical subjects

A L Notkins

Publications and source records attributed to A L Notkins.

At least 199 records · Page 11Linked to original sources
PubMed1980

Cytotoxic autoantibodies to beta cells in the serum of patients with insulin-dependent diabetes mellitus.

We studied serum from 36 patients with insulin-dependent diabetes mellitus (IDDM) for the capacity to lyse beta cells. Immunofluorescence revealed an islet-cell cytoplasmic antibody (ICA) in 20 patients with IDDM and an islet-cell-surface antibody (ICSA) in 23. Neither ICA nor ICSA was found in any of 21 normal controls or 15 patients with non-insulin-dependent diabetes. In the presence of complement. ICSA-positive serum caused significant lysis as measured by release of 51Cr (50.1 +/- 8.8 per cent) from cultured rat islet cells, but ICSA-negative serum did not (17.7 +/- 7.3 per cent) (P < 0.001). Proof that ICSA-positive serum was lytic for beta cells was obtained by a double-fluorescence technique that identified lysed cells by their capacity to take up ethidium bromide and beta cells by their staining with fluorescein-conjugated antibody to insulin. These findings suggest that cytotoxic ICSA contributes to the pathogenesis of IDDM, but the mere presence of ICSA does not appear to be sufficient to produce diabetes; family studies showed that one fourth of the serum samples from nondiabetic first-degree relatives of diabetic probands were ICSA-positive and cytotoxic for beta cells.

Adolescent↗
PubMed1980

Latency of herpes simplex virus in absence of neutralizing antibody: model for reactivation.

Mice inoculated with herpes simplex virus (type 1) by the lip or corneal route and then passively immunized with rabbit antibody to herpes simplex virus developed a latent infection in the trigeminal ganglia within 96 hours. Neutralizing antibody to herpes simplex virus was cleared from the circulation and could not be detected in most of these mice after 2 months. Examination of ganglia from the antibody-negative mice revealed latent virus in over 90 percent of the animals, indicating that serum neutralizing antibody is not necessary to maintain the latent state. When the lips or corneas of these mice were traumatized, viral reactivation occurred in up to 90 percent of the mice, as demonstrated by the appearance of neutralizing antibody. This study provides a model for identifying factors that trigger viral reactivation.

Animals↗
PubMed1980

Induction of diabetes by cumulative environmental insults from viruses and chemicals.

Encephalomyocarditis virus (EMC) induces diabetes in certain inbred strains of mice by infecting and destroying pancreatic beta cells, the severity of the diabetes depending on the number of beta cells destroyed. In strains of mice resistant to EMC-induced diabetes, insufficient beta cells are damaged to alter glucose homeostasis. However, diabetes can be produced in many species by streptozotocin, a highly specific beta-cell toxin. Here, we used concentrations of streptozotocin that did not produce diabetes, but reduced the beta-cell reserve. When strains of mice normally resistant to EMC-induced diabetes were first treated with sub-diabetogenic doses of streptozotocin, then infected with EMC virus, diabetes developed. Furthermore, when mice were infected with viruses such as Coxsackie B3 and B5, which ordinarily produce little if any beta-cell damage, diabetes developed if the mice were first treated with sub-diabetogenic doses of streptozotocin. These findings suggest that diabetes may result from cumulative beta-cell damage induced by sequential environmental insults.

Animals↗
PubMed1980

Herpes simplex virus DNA sequences in the CNS of latently infected mice.

It has been amply documented that herpes simplex virus (HSV) persists in sensory ganglia of the peripheral nervous system (PNS). In contrast, HSV latency in the central nervous system (CNS) has not been well characterized. Corneal inoculation of virus results in a productive viral infection in the CNS during the first week after inoculation, indicating that the virus can progress from the PNS to the CNS. During latency, HSV has been found by co-cultivation of CNS tissue in only a very small fraction of inoculated mice. We have used here molecular hybridization techniques to analyse the fate of viruses that reach the CNS by anatomical pathways. We show that 6 days after corneal inoculation of HSV-1 a productive viral infection was present in brain tissue as well as in peripheral ganglia in at least 90%F of the inoculated mice. The mortality during this acute phase was only 2%. In the survivors, latent HSV could be recovered by explantation from 95% of the trigeminal ganglia, but only 5% of the brain tissue explants of the same mice yielded infectious virus. However, HSV DNA sequences were detected in the brains of 30% of mice which harboured latent HSV in their trigeminal ganglia. These results suggest that viruses that progress from the PNS into the CNS are not eliminated, but are capable of establishing a latent infection in the CNS that cannot be reactivated by explantation techniques.

Animals↗
PubMed1980

Virus-induced diabetes mellitus. XVIII. Inhibition by a nondiabetogenic variant of encephalomyocarditis virus.

Plaque purification of the M variant of encephalomyocarditis (EMC) virus resulted in the isolation of two stable variants: one diabetogenic and designated D and the other nondiabetogenic and designated B. When the D variant was inoculated into SJL/J male mice, hypoinsulinemia and hyperglycemia developed in > 90% of the animals. In contrast, none of the mice inoculated with the B variant developed diabetes. Histologic examination of pancreata from mice infected with the D variant revealed insulitis and necrosis of beta cells, whereas islets from mice infected with the B variant showed little, if any, change. When islets were assayed for infectious virus, approximately 10 times more virus was recovered from animals inoculated with the D as compared with the B variant. Moreover, approximately 60% of islet cells from mice infected with the D variant contained viral antigens when stained with fluorescein-labeled anti-EMC virus antibody, whereas < 5% of islet cells from animals infected with the B variant contained viral antigens. Co-infection experiments showed that the induction of diabetes by the D variant was inhibited by the B variant. When the B and D variants were mixed together at B:D ratios of 1, 9, and 99, diabetes developed in 60, 11, and 0% of the mice, respectively. Tissue-culture experiments revealed that the B variant induced considerably more interferon than the D variant, and studies in animals showed that interferon appeared earlier and in greater amounts in the circulation of mice infected with the B as compared with the D variant. These studies suggest that the induction of interferon by the B variant is, at least in part, responsible for the inhibition of diabetes by the D variant.

Animals↗
PubMed1980

Pancreatic islet-cell damage in children with fatal viral infections.

The pancreases from 250 children with fatal infections caused by at least fourteen different viruses were examined for lesions in the islets of Langerhans. Viral cytopathology was found in 4 of 7 cases of Coxsackievirus B infection, 20 of 45 cases of cytomegalovirus infection, 2 of 14 cases of varicella-zoster infection, and 2 of 45 cases of congenital rubella. Destruction of beta cells and acute and chronic inflammatory infiltrates were found in islets from cases with Coxsackievirus B infections. Characteristic inclusion bodies were observed in islets from cases with cytomegalovirus and varicella-zoster infections. This survey provides further evidence that some viruses can infect and damage human beta cells.

Arbovirus Infections↗
PubMed1980

The role of interferon in immediate hypersensitivity and autoimmune diseases.

We have presented evidence showing that interferon can enhance the IgE-mediated release of histamine. We have also shown that immune interferon is present in the circulation of patients with certain autoimmune diseases. Furthermore, there is a positive correlation between active systemic lupus erythematosus and interferon levels. Systemic lupus erythematosus is characterized by immune hyperactivity. The continuous presence of type II, immune interferon in the circulation of these patients may, on one hand, contribute to the immunological aberrations, while on the other hand, protect against viral infections. At the present time we are looking for interferon in the circulation of patients with other autoimmune disorders.

Autoimmune Diseases↗
PubMed1980

Virus-induced decrease of insulin receptors in cultured human cells.

Viral infections may produce abnormalities in carbohydrate metabolism in normal subjects and profound changes in glucose homeostasis in insulin-dependent diabetics. Using an in vitro radio-receptor assay with 125I-labeled insulin and human-amnion (WISH) cells, the effect of viral infections on insulin receptors was examined. Both herpes simplex virus and vesicular stomatitis virus produced a 50% decrease in insulin binding. There was no evidence that this decrease was due to degradation of insulin. On quantitative analysis, this decrease in binding was found to be the result of a decrease in receptor concentration with no change in receptor affinity. The decrease in receptors occurred between 4 and 12 h, at the time viral antigens were being inserted into the plasma membrane of infected cells. Because the t 1/2 of insulin receptors in uninfected cells was between 14 and 24 h, the decrease in insulin receptors cannot be explained solely by virus-induced shut-off of macromolecular synthesis. Moreover, viruses such as encephalomyocarditis that do not insert new antigens into the plasma membrane, did not cause changes in the number of insulin receptors. The most likely explanation is that virus-induced changes in the plasma membrane altered or displaced insulin receptors. It is concluded that the insulin receptor assay is a sensitive and quantitative method for studying the effect of viral infections on cell membranes. These data also suggest that abnormalities in glucose metabolism associated with some viral infections may be due, in part, to changes in the concentration of insulin receptors.

Amnion↗
PubMed1980

Microculture system for studying monolayers of functional beta-cells.

A method is described for growing monolayers of newborn rat beta-cells in microculture trays. After disruption of the pancreas with collagenase, islets were isolated by Ficoll density gradient centrifugation, trypsinized to obtain individual cells, and plated in 96-well tissue culture trays. The cells were incubated for the first 3 days in growth medium containing 0.1 mM 3-isobutyl-1-methylxanthine to promote monolayer formation. The cultures could be maintained in a functional state, as defined by their responsiveness to known modulators of insulin secretion, for at least 2 weeks. As few as 1 X 10(3) islet cells/well gave results that were reproducible within +/- 10%. It is suggested that the microculture system for islet cells might prove to be a rapid and reproducible screening technique for studying drugs, viruses, or other agents that affect beta-cell function.

1-Methyl-3-isobutylxanthine↗
PubMed1980

Enhancement of IgE-mediated histamine release from human basophils by immune-specific lymphokines.

Human leucocytes (basophils) release histamine when exposed to ragweed antigen E or anti-IgE. The present study shows that when leucocytes from BCG-positive donors are first incubated with PPD and then challenged with anti-IgE, histamine release is enhanced. In contrast, when leucocytes from BCG-negative donors are incubated with PPD and then challenged with anti-IgE there is no enhancement of histamine release. The enhancement of histamine release was detected within 24 hr after addition of PPD, but was maximal at 48 to 72 hr. Supernatant fluids collected from these leucocyte cultures revealed the presence of a soluble mediator(s) which, when incubated with leucocytes from BCG-negative donors, enhanced the release of histamine. Examination of the supernatant fluids from BCG-positive leucocyte cultures stimulated with PPD showed a correlation between histamine-release enhancing activity and interferon. Treatment of the culture fluids at pH 2.0 abolished the anti-viral activity, indicating that the interferon was of the type II or 'immune' class. The same treatment only partly abolished the histamine-release enhancing activity. It is concluded that immune-specific stimulation of leucocytes results in the release of soluble mediators that are capable of enhancing IgE-mediated histamine release.

Adult↗
PubMed1979

Immune interferon in the circulation of patients with autoimmune disease.

The observation that type II, or immune, interferon could be produced by peripheral-blood leukocytes in vitro on an immune-specific basis suggested that it also might be produced in vivo in various autoimmune disorders. We found immune interferon in the serums of patients with systemic lupus erythematosus, rheumatoid arthritis, scleroderma and Sjögren's syndrome. Among 28 patients with systemic lupus erythematosus, 71 per cent of those with active and 21 per cent of those with inactive disease showed interferon in their serums. Serial serum samples showed a good correlation between interferon titers and disease activity. Moreover, interferon titers correlated positively with antibodies to DNA and negatively with serum levels of the third component of complement. It is possible that the production of interferon may contribute to immunologic aberrations in auto-immune diseases and also protect the already compromised host from viral infections.

Adult↗
PubMed1979

Isolation of a virus from the pancreas of a child with diabetic ketoacidosis.

A healthy 10-year-old boy was admitted to the hospital in diabetic ketoacidosis within three days of onset of symptoms of a flu-like illness. He died seven days later and post-mortem examination showed lymphocytic infiltration of the islets of Langerhans and necrosis of beta cells. Inoculation of mouse, monkey and human cell cultures with homogenates from the patient's pancreas led to isolation of a virus. Serologic studies revealed a rise in the titer of neutralizing antibody to this virus from less than 4 on the second hospital day to 32 on the day of death. Neutralization data showed that the virus was related to a diabetogenic variant derived from Coxsackievirus B4. Inoculation of mice with the human isolate produced hyperglycemia, inflammatory cells in the islets of Langerhans and beta-cell necrosis. Staining of mouse pancreatic sections with fluorescein-labeled antiviral antibody revealed viral antigens in beta cells. Both the clinical picture and animal studies suggested that the patient's diabetes was virus induced.

Animals↗
PubMed1979

Acute and latent infection of sensory ganglia with herpes simplex virus: immune control and virus reactivation.

The role of antiviral antibody in controlling the acute and latent phases of herpes simplex virus (HSV) infection in sensory ganglia of mice was studied in vitro and in vivo. Organ cultures of ganglia inoculated in vitro with HSV produced infectious virus for at least 3 weeks. In the presence of antiviral antibody, the titre of virus was markedly reduced, but the infection was not eliminated. Similarly, passive administration of antibody to HSV-infected immunodeficient (nude) mice reduced the virus titre but did not eliminate the acute phase of the ganglionic infection. Suppression of the cell-mediated immune response in latently infected immunocompetent mice by treatment with cyclophosphamide and/or X-irradiation resulted in reactivation of HSV in up to 70% of the animals. Reactivation was demonstrated by recovering infectious virus in cell-free homogenates of ganglia and eye globes and by finding virus antigens in ganglia by immunofluorescent staining. Reactivation occurred both in vitro and in vivo in the presence of high concentrations of neutralizing antibody. It is concluded that antibody alone is not sufficient to eliminate the acute phase of the ganglionic infection and that cytotoxic agents known to suppress the host's cellular immune response can reactivate virus in the presence of neutralizing antibody.

Animals↗