Cytokine release by murine spleen cells following multiple low dose streptozotocin-induced diabetes and treatment with a TNFa transcriptional inhibitor Lina Thorvaldson * , Maria Holstad, Stellan Sandler Department of Medical Cell Biology, Biomedical Centre, Uppsala University, Box 571, Husargatan 3, SE-751 23 Uppsala, Sweden Received 17 April 2003; received in revised form 2 June 2003; accepted 30 June 2003 Abstract We recently reported that administration of 9-[(1R,3R)-trans-cyclopentan-3-ol] adenine (MDL 201,449A), a transcriptional inhibitor of TNFa , decreased hyperglycemia in murine diabetes induced by multiple low doses of streptozotocin (MLDSTZ). In the present study, we first investigated if in vivo administration of MDL 201,449A in the MLDSTZ model affects cytokine release from cultured spleen cells. Secondly, we studied how MDL 201,449A affects cytokine release from normal cultured spleen cells. In all experiments, the mitogen concanavalin A (2 Ag/ml) was added to the cultured spleen cells in order to enhance cytokine release. MLDSTZ treatment in vivo caused increased IFNg secretion, a decreased/retarded rate of increased TNFa accumulation, whereas IL-10 production was not altered compared to vehicle-treated mice. MDL 201,449A treatment of MLDSTZ mice did not affect cytokine release from spleen cells subsequently cultured in the absence of MDL 201,449A. We also studied cytokine release from normal spleen cells in the presence or absence of MDL 201,449A. Production of TNFa , IFNg and IL-10 was all suppressed by the drug. In groups where exposure to MDL 201,449A was discontinued, cytokine levels increased promptly and in the case of TNFa secretion, it exceeded the production from control cells. Our data suggest an enhanced Th1 cytokine secretion from spleen cells derived from MLDSTZ-treated mice. MDL 210,449A may be a potent inhibitor of cytokine secretion, albeit not completely selective for TNFa . However, when MDL 201,449A is withdrawn, there may be a rebound phenomenon of increased TNFa secretion. D 2003 Elsevier B.V. All rights reserved. Keywords: Cytokine; Mice; Streptozotocin; TNFa; Type 1 diabetes 1. Introduction h-Cell destruction in type 1 diabetes probably involves cytokines produced by T cells [1]. The balance between cytokines produced by T helper 1 and 2 (Th1 and Th2) lymphocytes has been postulated to influence the outcome of the disease. Th1 responses are often associated with defence against infections, whilst Th2 responses are noted in connection to helminth infections and allergic reactions [2,3]. In type 1 diabetes, a Th1 response (a cytokine production dominated by e.g. TNFa , IFNg, IL-1h, IL-2 and IL- 12) has been suggested to be connected with a h-cell 1567-5769/$ - see front matter D 2003 Elsevier B.V. All rights reserved. doi:10.1016/S1567-5769(03)00183-8 * Corresponding author. Tel.: +46-18-4714411; fax: +46-18- 471-40-59. E-mail address: Lina.Thorvaldson@medcellbiol.uu.se (L. Thorvaldson). www.elsevier.com/locate/intimp International Immunopharmacology 3 (2003) 1609 – 1617