Macrophage migration inhibitory factor and development of type-1 diabetes in non-obese diabetic mice Jo¨rg Bojunga a, * , Klaus Kusterer a , Michael Bacher b , Ralf Kurek c , Klaus-Henning Usadel a , Heiner Renneberg d a Department of Medicine I, Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, 60590 Frankfurt/Main, Germany b Department of Immunology, Philipps-University, 35033 Marburg, Germany c Department of Radiation Oncology, Academic Hospital, 63069 Offenbach; Germany d Human Biology Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA Received 10 June 2002; received in revised form 20 February 2003; accepted 24 February 2003 Abstract Aims/hypothesis: T-cell activation by specific antigen has been found to increase macrophage migration inhibitory factor (MIF) expression, indicating its role as an important feature of T-cell activation in vitro and in vivo. To date, the potential role of MIF in the development of autoimmune-mediated diabetes mellitus has not been studied. Methods: MIF-mRNA expression in splenic lymphocytes of spontaneously diabetic non-obese diabetic (NOD) mice ðn ¼ 6Þ, cyclophosphamide-treated NOD mice ðn ¼ 6Þ, 14-day-old non-diabetic NOD mice ðn ¼ 7Þ and C57/Bl6 control mice ðn ¼ 6Þ was monitored using an internally standardised competitive reverse transcription-polymerase chain reaction, and the MIF-protein levels were determined using Western blot analysis. In addition, the impact of intraperitoneally administered recombinant MIF-protein treatment on diabetes incidence in NOD mice was evaluated. Results: MIF-mRNA expression was markedly increased in splenic lymphocytes of spontaneously diabetic NOD mice as well as in 8-week-old NOD mice treated with cyclophosphamide compared with 2-week-old non-diabetic NOD and healthy C57BL/6 control mice. Western blot analyses showed decreased lymphocytic MIF-protein content in diabetic as well as in cyclophosphamide-treated animals compared with 2-week-old non-diabetic NOD and healthy C57BL/6 mice, probably as a consequence of increased protein secretion. Furthermore, treatment of NOD mice with recombinant MIF-protein at 25 lg twice a week, from age 6 to 11 weeks, led to an increased diabetes incidence (86%; n ¼ 7) compared with untreated control groups (55%; n ¼ 20) at week 34. Conclusions/interpretation: In this study, we report for the first time that MIF-mRNA expression in splenic lymphocytes is up- regulated during development of cell-mediated diabetes in non-NOD mice. The data of our preliminary study suggest a possible role of MIF in autoimmune-inflammatory events, such as type-1 diabetes and also that anti-MIF therapeutic strategy might serve to attenuate autoimmune processes. Ó 2003 Elsevier Science Ltd. All rights reserved. Keywords: Experimental diabetes; Cyclophosphamide; Competitive reverse transcription-polymerase chain reaction; Lymphocytes; Non-obese diabetic mouse; C57/Bl6 mouse 1. Introduction T-cell derived inflammatory cytokines play an im- portant role in the development of type-1 diabetes, and diabetes-promoting as well as diabetes-protecting cyto- kines have been reported [1,2]. Macrophage migration inhibitory factor (MIF) was originally described more than 30 years ago as a T-cell-derived factor that inhib- ited the random migration of macrophages in vitro [3,4]. In the early 1990s, it was ÔrediscoveredÕ as a sec- reted hormone of the anterior pituitary gland, which counter-regulates the anti-inflammatory effects of gluco- corticoids [5]. In addition, MIF has an essential role in the modulation of macrophage activation and in mitogen, receptor cross-linking, as well as in specific antigen-driven T-cell activation [6] (for review see Cytokine 21 (2003) 179–186 www.elsevier.com/locate/jn/abr/ycyto * Corresponding author. Tel.: +49-69-6301-5396; fax: +49-69-6301- 6405. E-mail address: dr_bojunga@web.de (J. Bojunga). 1043-4666/03/$ - see front matter Ó 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S1043-4666(03)00076-0