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.
Ludwig
R
R
Department of Medicine I, J.W. Goethe University, Frankfurt am Main, Germany.
Kretschmer
M
M
Caspar
G
G
Bojunga
J
J
Oldenburg
A
A
Schumm-Draeger
P
P
Stegmüller
M
M
von Minckwitz
G
G
Usadel
K H
KH
Kusterer
K
K
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002448:Cell Adhesion / Q000276:immunology; D016009:Chi-Square Distribution; D016207:Cytokines / Q000276:immunology*; D003921:Diabetes Mellitus, Experimental / Q000276:immunology* / Q000378:metabolism; D005434:Flow Cytometry; D007150:Immunohistochemistry; D039041:Integrin alpha4beta1; D016023:Integrins / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D007371:Interferon-gamma / Q000276:immunology; D007375:Interleukin-1 / Q000276:immunology; D007515:Islets of Langerhans / Q000737:chemistry / Q000276:immunology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis; D008214:Lymphocytes / Q000502:physiology*; D008264:Macrophages / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D016201:Receptors, Lymphocyte Homing / Q000032:analysis; D018709:Statistics, Nonparametric; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis
D000911:Antibodies, Monoclonal; D016207:Cytokines; D039041:Integrin alpha4beta1; D016023:Integrins; D007375:Interleukin-1; D016169:Lymphocyte Function-Associated Antigen-1; D016201:Receptors, Lymphocyte Homing; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma