PT - JOURNAL ARTICLE AU - Im, Sin-Hyeog AU - Barchan, Dora AU - Maiti, Prasanta Kumar AU - Fuchs, Sara AU - Souroujon, Miriam C. TI - Blockade of CD40 Ligand Suppresses Chronic Experimental Myasthenia Gravis by Down-Regulation of Th1 Differentiation and Up-Regulation of CTLA-4 AID - 10.4049/jimmunol.166.11.6893 DP - 2001 Jun 01 TA - The Journal of Immunology PG - 6893--6898 VI - 166 IP - 11 4099 - http://www.jimmunol.org/content/166/11/6893.short 4100 - http://www.jimmunol.org/content/166/11/6893.full SO - J. Immunol.2001 Jun 01; 166 AB - Myasthenia gravis (MG) and experimental autoimmune MG (EAMG) are T cell-dependent Ab-mediated autoimmune disorders, in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. Th1-type cells and costimulatory factors such as CD40 ligand (CD40L) contribute to disease pathogenesis by producing proinflammatory cytokines and by activating autoreactive B cells. In this study we demonstrate the capacity of CD40L blockade to modulate EAMG, and analyze the mechanism underlying this disease suppression. Anti-CD40L Abs given to rats at the chronic stage of EAMG suppress the clinical progression of the autoimmune process and lead to a decrease in the AChR-specific humoral response and delayed-type hypersensitivity. The cytokine profile of treated rats suggests that the underlying mechanism involves down-regulation of AChR-specific Th1-regulated responses with no significant effect on Th2- and Th3-regulated AChR-specific responses. EAMG suppression is also accompanied by a significant up-regulation of CTLA-4, whereas a series of costimulatory factors remain unchanged. Adoptive transfer of splenocytes from anti-CD40L-treated rats does not protect recipient rats against subsequently induced EAMG. Thus it seems that the suppressed progression of chronic EAMG by anti-CD40L treatment does not induce a switch from Th1 to Th2/Th3 regulation of the AChR-specific immune response and does not induce generation of regulatory cells. The ability of anti-CD40L treatment to suppress ongoing chronic EAMG suggests that blockade of CD40L may serve as a potential approach for the immunotherapy of MG and other Ab-mediated autoimmune diseases.