Biomedical subjects

G Caspar

Publications and source records attributed to G Caspar.

7 recordsLinked to original sources

PubMed2004

Lymphocyte homing in xenotransplanted human thyroid tissue can be inhibited by LFA-1 and ICAM-1 antibodies.

OBJECTIVES: Homing of lymphocytes is an important factor with respect to the initiation of the autoimmune process in Graves' disease (GD). As previously shown, human lymphocytes, particularly of intrathyroidal origin, derived from patients with GD, are able to migrate into normal xenotransplanted thyroid tissue and induce functional and histological changes. The aim of this study was to investigate the effect of LFA-1 and ICAM-1 antibodies on the homing of lymphocytes of different origin into xenografted human thyroid tissue. METHODS: Eighty-five nude mice bearing 8-week-old xenografts of normal human thyroid tissue were treated twice with anti-CD 54 (anti-ICAM-1), anti-CD 11a (anti-LFA-1), a combination of both, or, serving as controls, iso-antibodies without specific binding capacity or saline. Thereafter, intrathyroidal (ITL) or peripheral blood lymphocytes (PBL) obtained from 4 patients with GD or saline were injected into the animals (i.v., 0.2 mL, 10(6) cells). After 48 hours the mice were sacrificed and transplants as well as mice thyroids were examined by immunohistochemical staining with Ki67, CD3, HLA-II (DAKO, Hamburg), IgG, CD44, ICAM-1, and VCAM-1 (Immunotech, Hamburg). RESULTS: Pretreatment with anti-ICAM-1 and anti-LFA-1 decreased lymphocyte homing (CD3-staining), and expression of HLA-II, IgG, CD44, and VCAM-1 in the transplants. CONCLUSION: Our data show that [ICAM-1/LFA-1 stimulated (induced)] lymphocyte homing and subsequently thyrocyte proliferation are inhibited by ICAM-1 and LFA-1 antibodies in xenotransplanted thyroid tissue. This suggests that ICAM1 and LFA-1 play an important role in the early steps of autoimmune thyroid disease. The inhibition/suppression of ICAM-1 and LFA-1 interaction by respective antibodies, as demonstrated in the present study, may provide a new concept for prophylaxis and therapy.

Animals↗

PubMed2001

Expression of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 and homing factor CD44 after engraftment of Graves' lymphocytes in xenotransplanted human thyroid tissue in athymic nude mice.

The expression of adhesion molecules on thyrocytes and endothelium cells plays an important role in the pathogenesis of Graves' disease (GD). The intercellular adhesion molecule-1 (ICAM-1), the vascular cell adhesion molecule-1 (VCAM-1), and the homing receptor CD44 are responsible for the specific migration of lymphocytes in autoimmune thyroid diseases (AITD) (homing). Eight weeks after transplantation of thyroid tissue from 26 patients with nonautoimmune thyroid disease (nontoxic nodular goiter [NTG]) into nude mice, peripheral (PBL) and intrathyroidal lymphocytes (ITL) from 14 patients with NTG and 12 patients with GD were grafted into the animals. Two days after lymphocyte engraftment, the thyroid transplants were examined histologically (HE) and immunohistologically stained with monoclonal antibodies directed against ICAM-1, VCAM-1, and CD44. After injection of GD lymphocytes, thyroid transplants expressed significantly more ICAM-1, VCAM-1, and CD44 than after injection of NTG lymphocytes. This expression was even more pronounced after grafting of GD intrathyroidal lymphocytes. Our data demonstrate that only GD lymphocytes induce the expression of adhesion molecules and homing factor CD44, both of which play an important role in the migration of lymphocytes and induction of the autoimmune process.

Animals↗

PubMed1999

In vivo microscopy of murine islets of Langerhans: increased adhesion of transferred lymphocytes to islets depends on macrophage-derived cytokines in a model of organ-specific insulitis.

Environmental factors contribute to the pathogenesis of type 1 diabetes (insulin-dependent diabetes mellitus). Multiple low doses of streptozotocin (MLDS) induce hyperglycaemia and insulitis in mice. Previously we demonstrated that adhesion of lymphocytes to endothelium of islets is only increased when donor animals were diabetic and recipient mice had received 5 mg/kg streptozotocin (STZ). Therefore we used streptozotocin to evaluate the immunological relevance of such an irritation of islets. Lymphocytes, separated from diabetic mice (MLDS), were fluorescently labelled and injected to recipient mice that had received 5 mg/kg STZ. With in vivo microscopy we measured lymphocyte flow and adherence in islets. Expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1) in the pancreas was assessed using immunohistochemistry. Very late antigen-4 (VLA-4) and leucocyte function-associated antigen-1 (LFA-1) expression on transferred lymphocytes was measured with flow cytometry. Pretreatment of recipients with antibodies to cytokines or silica reduced lymphocyte adherence to islet endothelium from 2.04% (goat immunoglobulin G; IgG) or 1.82% (rat IgG) to 0.47, 0.58, 0.39 or 0. 19% for monoclonal antibody (mAb) interferon-gamma (IFN-gamma), polyclonal antibody (pAb) tumour necrosis factor-alpha (TNF-alpha), pAb interleukin (IL)-1alpha or silica, respectively. Reduced adhesion was associated with a decreased expression of VCAM-1 and ICAM-1 in islets of treated recipients compared with mice treated with 5 mg/kg STZ alone. In conclusion, pretreatment of recipients with 5 mg/kg STZ leads to an increased expression of adhesion molecules in the islets and lymphocyte adhesion to islet endothelium in vivo, demonstrating an immune response of the islets. Prevention of increased expression of ICAM-1 or VCAM-1 and reduction of lymphocyte adhesion in islets by silica or antibody indicate an involvement of macrophages and macrophage derived cytokines in the generation of this immune response.

Animals↗

PubMed1999

Immunologic effects of human peripheral and intrathyroidal lymphocytes on xenotransplanted human thyroid tissue in athymic nude mice.

T cells are intimately involved in the etiology and pathogenesis of human autoimmune thyroid disease. In order to further elucidate the immunologic mechanisms leading to Graves' disease (GD), we investigated the effects of human lymphocytes derived from patients with autoimmune and nonautoimmune thyroid diseases on human thyroid tissue xenotransplanted into nude mice. Eight weeks after transplantation of thyroid tissue from 26 patients with nonautoimmune thyroid disease (nontoxic nodular goiter [NTG]) into nude mice, peripheral (PBL) and intrathyroidal lymphocytes (ITL) from 14 patients with NTG and 12 patients with GD were engrafted into the animals. ITL and PBL subsets were analyzed by flow cytometer before engraftment. Two days after lymphocyte engraftment, the thyroid transplants were examined histologically (HE) as well as immunohistologically by staining with monoclonal antibodies directed against CD3 (T-cell activation and signal transduction), immunoglobulin G (IgG), HLA class II and CD31 (human endothelium). After injection of GD lymphocytes, thyroid transplants contained significantly more CD3, HLA class II, and CD4 expressing cells. Engrafted PBL and especially ITL from patients with GD specifically migrated into human thyroid transplants but not into the mouse thyroids, induced expression of class II products and led to IgG production by plasma cells. Persistence of human endothelium has been proven by positive CD31 staining. In conclusion, our data demonstrate that an organ-specific immune response is induced only by GD lymphocytes that migrate specifically into the thyroid transplants. Persistence of human endothelial cells in the transplants suggests that homing in this in vivo model reflects the situation in GD patients.

Adult↗

PubMed1996

Effect of Graves' intrathyroidal lymphocytes. Effect of Graves' disease intrathyroidal lymphocytes (ITL) on xenotransplants of human thyroid tissue in athymic nude mice.

It has been suggested that ITL are of importance in the pathogenesis of human autoimmune thyroid disease. Aim of our study was to investigate function and morphology of xenotransplanted human thyroid tissue in nude mice following systemic application of lymphocyte preparations from patients with Graves' disease (GD) and non-toxic nodular goiter (NTG). ITL obtained from 13 patients with GD and peripheral blood lymphocytes (PBL) from 12 patients with NTG were injected into nude mice bearing 8 weeks old xenografts of normal human thyroid tissue. ITL- and PBL-subsets were analyzed by flow cytometer (FACScan) before engraftment. Two days after injection the thyroid transplants were examined histologically (HE) as well as immunohistologically by staining with: CD3, CD31, CD45R, HLA class II, ICAM-1, VCAM-1, IgG, IgM and Ki67. Flow cytometry showed a significant higher number of the lymphocyte-subsets CD3, DR+ and CD4 in GD-ITL as compared to the subsets in NTG-ITL. After injection of GD-ITL to the nude mice also a significant higher number of CD3+ human lymphocytes was found in the transplants. GD-lymphocytes stimulated thyroid tissue function significantly more pronounced than NTG-lymphocytes (histomorphological evaluation). In addition, a significant increase of HLA-class II, ICAM-1-, VCAM-1-, CD45-expression and number of Ig presenting plasma cells were observed only after injection of GD-ITL. Our data demonstrate, for the first time in vivo (nude mouse model), that GD-lymphocytes of both peripheral and intrathyroidal origin selectively migrate into human thyroid transplants ("homing"). They survive there for at least two days and induce significant functional as well as histological changes, like expression of gene products and IgG synthesis. These results suggest an important role of ITL in the pathogenetic mechanisms and clinical course of GD.

Animals↗

PubMed1996

[Spontaneous Hashimoto-like thyroiditis in cats].

A breeding line of domestic cats spontaneously developing symptoms of hypothyroidism between the 40th and 60th day of life (fur changes, loss of appetite, growth retardation), elevated levels of antibodies against microsomal structures and thyroglobulin, and lymphocytic thyroid infiltration has been recently established at our facility. Aim of our studies was to examine the effect of high iodine ingestion or prophylactic thyroid hormone therapy on functional and morphological characteristics of this Hashimoto-like thyroiditis in cat. From birth to day 80 of life cats were treated with iodine (n = 9; 0.1 mg/l) or thyroxin (n = 13; 2.0 micrograms/ kg/d) respectively. Untreated animals served as controls (n = 12). Cat-serum was tested for thyroid function (TT3, TT4). After 8 weeks the thyroid tissue was submitted to routine histological processing (H&E) and the inflammatory activity was scored. Additionally immunohistological staining was performed for MIB-1, IgG, IgM and MHCII expression. Both untreated hypothyroid (UHC) as well as iodine-treated (IC) cats revealed a significantly higher degree of thyroid inflammation and higher tissue levels of IgM as the thyroxin-substituted animals (TC). Epithelial proliferation decreased significantly in the IC and TC groups as compared to the untreated controls. No significant differences regarding IgG production and HLAII expression were detectable. Early thyroid hormone therapy significantly decreases both incidence and activity of autoimmune thyroiditis in cats as measured by inflammatory infiltration, IgM production and epithelial proliferation. Animals with excess iodide intake, however, show an aggravation of the autoimmune inflammatory activity.

Animals↗

PubMed1996

[Effect of intrathyroidal lymphocytes of Graves' disease patients on xenograft thyroid tissue in the athymic nude mouse].

In this study we investigated the functional and morphological properties of xenotransplanted human thyroid tissue in nude mice following systemic application of intrathyroidal lymphocyte preparations from patients with Graves' disease (GD) and non-toxic nodular goiter (NTG). Thyroid tissue samples from 17 NTG-patients were transplanted into athymic nude mice for a period of 4-5 weeks. Aliquots of lymphocyte preparations from both peripheral blood samples (PBL) and thyroid tissue (ITL) of 13 patients with GD and 12 patients with NTG were analyzed by flow-cytometry (CD3, CD4, CD8, CD56) and injected (i.v.) into transplanted nude mice. Animals injected with saline solution served as a control. After 48 h transplants were harvested and histological (H&E) as well as immunohistological evaluation was performed (MHCII, IgG, IgM). Control animals and mice treated with both PBL and ITL from NTG patients showed regular thyroid tissue without lymphocytic infiltrates or local expression of human immunoglobulins. Application of PBL and ITL of GD patients caused scant to moderate lymphocytic infiltrates with detection of human immunoglobulin production. Injection of GD-ITL was accompanied by a significantly higher proportion of intrathyroidal CD3+ lymphocytes and MHCII expression of adjacent thyroid epithelium as compared to injection of GD-PBL preparations. Our results demonstrate that GD-lymphocytes of both peripheral but especially intrathyroidal origin migrate specifically to human thyroid transplants in the nude mouse model, survive for at least two days, secrete immunoglobulins and induce MHCII expression.

Animals↗