Immunomodulation of Activated Immune Cells in Experimental Autoimmune Encephalomyelitis (EAE) (42.7)

Abstract The relapse rate is profoundly decreased in female multiple sclerosis (MS) patients during pregnancy. We previously reported that experimental autoimmune encephalomyelitis (EAE), an animal model of MS, is markedly suppressed when disease is induced during late pregnancy. Disease induction during the post partum period is enhanced. In this study, we assess the effects of pregnancy on activated T cells by transferring neuroantigen activated transgenic T cells into pregnant syngeneic wild type recipients (B10.PL). Myelin basic protein (MBP) TCR transgenic (Tg) donor splenocytes are activated in vitro with MBP NAc1-11 for 96 hours. These CD4+CD25+Foxp3- donor cells elicited a strong proliferative response and an increase in Th1 cytokines. The activated T cells were transferred i.v. into pregnant recipients and non-pregnant controls. Control mice showed acute and relapsing EAE, while pregnant recipients showed significantly reduced cumulative disease scores. Furthermore, pregnancy inhibited T cell proliferation and increased the number of B cells post transfer. The role of regulatory/suppressive T cells and inhibitory molecules on antigen presenting cells (B cells and DCs) are under study for their involvement in pregnancy suppression of EAE (Supported by NIH grant AI 43376).