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R S Sundick

Publications and source records attributed to R S Sundick.

9 recordsLinked to original sources
PubMed1992

Marek's disease virus-transformed chicken T-cell lines respond to lymphokines.

Current assays for chicken interleukin-2 (IL-2) utilize mitogen-activated lymphocytes. However, very high inter-assay variability and sporadic high background proliferation limit their usefulness. In view of the above, several Marek's disease virus (MDV)-transformed T-cell lines (which grow well in a serum-supplemented medium) were tested for a response to chicken IL-2 when grown in serum-free media. Five of six lines examined showed a dose-dependent proliferative response to chicken T-cell conditioned media. One line, MDCC-CU14, was chosen for further studies. In addition to the tumor cells' dose-dependent responses to semi-purified chicken IL-2, they expressed T-cell activation antigens on the cell surface. Furthermore, the level of surface expression was enhanced on cells provided IL-2. Co-incubation of the tumor cells with monoclonal antibody INN-CH-16 (specific for an antigen on the surface of activated T-cells) and IL-2 resulted in a modulation of lymphokine-induced proliferation. Together, these data suggest that signalling mechanisms in MDV T-cell tumors are intact and that these lines can be used as an assay for chicken T-cell lymphokines. Furthermore, they provide an interesting model for the study of avian and mammalian T-cell transformation. Implications for the study of Marek's disease are also discussed.

Animals↗
PubMed1992

The role of iodine in thyroid autoimmunity: from chickens to humans: a review.

Evidence has been presented to support the idea that iodine plays an important role in autoimmune thyroiditis. Excessive amounts induce thyroiditis in genetically susceptible animal strains, while intrathyroidal depletion of iodine prevents disease in strains susceptible to severe thyroiditis. While the mechanisms by which iodine promotes thyroiditis is unknown, several hypotheses have been proposed. (1) T and/or B cells may react specifically to iodinated portions of thyroglobulin (Tg) so that severe iodine depletion renders Tg non-immunogenic. (2) A defect in the iodine processing machinery in thyroid epithelial cells of a susceptible person or animal may, in the presence of iodine, result in elevated levels of oxygen or iodine radicals, which could damage membrane lipids or proteins. (3) Defective iodine processing may result in the iodination of lipid or proteins (other than Tg) which could act either as immunogens or polyclonal activators.

Animals↗
PubMed1991

Uptake and metabolism of iodine is crucial for the development of thyroiditis in obese strain chickens.

To assess the importance of the role of thyroidal iodine in the pathogenesis of thyroiditis in the obese strain (OS) chicken, a model of spontaneous and severe disease, we studied the effect of antithyroid drugs that reduce thyroidal iodine or prevent its metabolism. Reduction of thyroidal iodine was achieved with KClO4, an inhibitor of iodine transport and mononitrotyrosine (MNT), a drug that promotes loss of thyroidal iodine as iodotyrosines. A regimen consisting of KClO4 and MNT administration beginning in ovo and continuing after hatching reduced thyroidal infiltration to 2% of control values and decreased thyroglobulin antibody (TgAb) production for as long as 9 wk. Untreated birds had severe disease by 5 wk of age. The suppression of disease was independent of TSH, not mediated by generalized immunosuppression and reversed by excess dietary iodine. Two drugs that inhibit the metabolism of iodine, propylthiouracil (PTU) and aminotriazole, reduced thyroidal infiltration and TgAb levels, although to a lesser extent. When splenocytes from OS chickens with thyroiditis were transferred to Cornell strain (CS) chickens, a related strain that develops late onset mild disease, only the recipients that were iodine supplemented developed thyroiditis. In conclusion, autoimmune thyroiditis in an animal model can be prevented by reducing thyroidal iodine or its metabolism and optimal effects require intervention at the embryonic stage.

Amitrole↗
PubMed1977

Genetic and cellular control of spontaneous autoimmune thyroiditis in OS chickens.

B-locus genotypes have been defined in Obese strain (OS) chickens that spontaneously develop autoimmune thyroiditis (SAT), and in White Leghorn Cornell C strain (CS) chickens from which the OS was selected. The B-locus influences SAT, and some possible mechanisms are discussed. Thymic abnormalities in OS, as contrasted with CB birds, are also discussed and may play a role in SAT, as may an intrinsic defect in the thyroid gland itself.

Animals↗
PubMed1976

Abnormal response to minor histocompatibility antigens in Obese strain chickens.

Obese strain chickens, which spontaneously develop autoimmune thyroiditis, were tested for their ability to tolerate skin allografts. Several procedures known to prolong graft survival in normal strains were employed. These included the use of skin matched at the major histocompatibility locus, grafting on the day of hatching, thymectomy, and x-irradiation. A dramatic difference between the Obese and the normal Cornell strain (the strain from which Obese was derived) was detected when both were thymectomized and grafted at hatching. Under these conditions eight of 13 normal but only one of 16 Obese strain birds retained their grafts for 50 days. This suggests the presence of an abnormal thymus or thymus-derived suppressor T cells in Obese strain chickens.

Age Factors↗
PubMed1976

Increased iodine uptake by obese strain thyroid glands transplanted to normal chick embryos.

The Obese strain (OS) of chickens spontaneously develops autoimmune thyroiditis. Since a defect or abnormality of the thyroid gland may be involved in this disease experiments were performed to compare the iodine uptake of OS with normal thyroid glands. To minimize the interaction of the OS immune system with the thyroid gland during these studies, thyroids were removed from 16-day-old embryos and transferred to the chorioallantoic membrane (CAM) of 9-day-old normal White Leghorn (NWL) embryos. NWL thyroid glands were transferred to the same CAM. Six days later the 20-hr 131I uptake of the transplants was determined. Twenty OS thyroid lobes had a mean 131I uptake of 2960 +/- 740 cpm, whereas the NWL thyroids incorporated significantly less iodine (890 +/- 160 cpm; p less than 0.025). These results, along with a previous report suggest that an abnormality of the thyroid gland might be an important factor in the development of autoimmune thyroiditis.

Animals↗