conditions such as atopic dermatitis (AD). Previously, we found that the EGCG could improve AD-like skin lesions of NC/Nga mice by suppressing the macrophage migration inhibitory factor (MIF) and other T helper (Th) 1-related cytokines. MIF has been re-evaluated as a pro-inflammatory cytokines, and the over-expression of MIF stimulates Th1, and prolongs an exaggerated inflammation. From these evidences, it is conceivable that MIF contributes to the immunologic dysregu- lation in AD. However, so far, few experiments have assessed the effect of EGCG in MIF-induced inflammation and immune deviation in keratinocytes in vitro. The aim of this study was to assess the anti-inflammatory effect of EGCG and to evaluate how MIF affects Th-related chemokine and cytokine expression on keratinocytes. First, HaCaT cell growth induced by various concentrations of EGCG treatment was monitored using the 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay. HaCaT cells were stimulated with recom- binant TNF-α or MIF with or without various concentrations of EGCG. Finally, MIF, IL-8, and Th-related chemokines and cytokines were measured by using RT-PCR, Western blot, ELISA and immunofluorescence staining. EGCG treatment did not significantly affect cell viability. EGCG suppressed recombi- nant TNF-α-induced MIF and IL-8 expression on HaCaT cells in a dose-dependent fashion (Pb0.05). Interestingly, Th1-related chemokines (CXCL9, CXCL10, CXCL11) were significantly up- regulated when treated with recombinant MIF, compared to no treatment (Pb0.05). These results demonstrate that EGCG has an anti-inflammatory effect by regulating MIF-induced Th- related chemokines and cytokines in human HaCaT cells. doi:10.1016/j.clim.2010.03.375 S.54. Role of Delta-like4/Notch Pathway in Experimental Autoimmune Encephalitis Ribal Bassil 1 , Youmna Lahoud 1 , Bing Zhu 1 , Hideo Yagita 2 , Wassim Elyaman 1 , Samia Khoury 1 . 1 Brigham and Women's Hospital, Boston, MA; 2 Juntendo University School of Medicine, Tokyo, Japan Notch signaling pathway has been shown to regulate a broad range of events at several developmental stages including T-helper cell differentiation. However, the role of Notch signaling in autoimmunity is still not completely understood. Notch receptors on peripheral T-cells are activated by Notch ligands, including Delta-like1, Delta- like4 (Dll4), Jagged1 and Jagged2, expressed on antigen presenting cells. To study Notch ligand expression on APCs during EAE, C57/BL6 mice were immunized with MOG35-55/ CFA and APCs subsets - myeloid, lymphoid, plasmacytoid dendritic cells, macrophages, inflammatory monocytes and B cells - were isolated by FACS sorting on days 0, 3, 6, 9 and 13 post-immunization. Analysis of Notch ligand expression by Taqman PCR shows that Dll4 increases during EAE progression on lymphoid DCs, which are thought to primarily stimulate cell-mediated Th1 responses in mice. To assess the role of Dll4 in autoimmunity, mice were treated with anti-Dll4 blocking antibody or control IgG between days 0 and 10 after immunization. Administration of anti-Dll4 antibody during the priming phase but not the effector phase (Days 10 - 20) reduced the severity of the clinical disease and CNS in- flammation. This was associated with a decrease in CD4+ IFNγ+ T cell frequency and an increase in CD4+IL-4+ cells as analyzed by FACS and Luminex. Moreover, blockade of Dll4 signaling induced an increase in CD4+FoxP3+ T cell frequen- cy. Anti-Dll4 administration also increased T cell proliferation but decreased T-cell survival. Our present findings demon- strate the pathogenic role of Delta-like4 in EAE, and suggest it as a potential therapeutic target for autoimmune diseases. doi:10.1016/j.clim.2010.03.376 S.55. Neonatal Fc Receptor Dependent Acquisition of Allergic Protection Adam Matson 2 , Roger Thrall 1 , Ektor Rafti 2 , Lynn Puddington 1 . 1 University of Connecticut Health Center, Farmington, CT; 2 Connecticut Children's Medical Center, Hartford, CT The mechanism(s) responsible for the reduced risk of allergic disease in breastfed infants are not fully understood. Using a murine model of allergic airway disease (AAD) we demonstrated the ability of breast milk from allergic mothers to protect offspring from AAD is dependent on intact maternal B cell immunity (Matson et al., 2009). The aim of this study was to investigate the role of the neonatal Fc receptor for IgG uptake by intestinal epithelial cells (FcRn) in this maternally transferred protection. C57BL/6J OVA-immune foster mothers (B6AAD) were generated (re-exposed to aerosolized OVA on days 11-17 of pregnancy) to nurse pups with or without FcRn. Levels of maternal OVA-specific antibodies absorbed from breast milk were determined in weanling FcRn +//0 , FcRn +//0 , or FcRn -/- mice. As expected, transmission of OVA-specific IgG 1 antibodies from mothers to breastfed FcRn -/- offspring was at levels 10 3 -10 4 lower than observed in FcRn +//0 or FcRn +//0 mice. Following weaning, when offspring were 8 wk old, mice were immunized and challenged to elicit OVA-induced AAD. Protection, indicated by reduced parameters of AAD (OVA- specific IgE in serum and inflammation in the respiratory tract) was evident in FcRn-sufficient offspring nursed by B6AAD mothers. In contrast, limited, if any, protection from deve- lopment of OVA-induced AAD was transmitted from allergic mothers to FcRn-deficient offspring. These data demonstrated that FcRn expression was required for breastfed offspring to acquire sufficient levels of systemic allergen-specific IgG 1 to mediate protection in this model. doi:10.1016/j.clim.2010.03.377 S.56. Characterisation of Mice with B Cell Specific WASP Deficiency Mike Recher 1 , Miguel Fuente 1 , Laura Patrizi 1 , Jolan Walter 1 , Siobhan Burns 2 , Adrian Thrasher 2 , Luigi Notarangelo 1 . 1 Childrens Hospital, Boston, MA; 2 Institute of Child Health, London, United Kingdom The Wiskott-Aldrich Syndrome (WAS) is a severe X-linked primary immune deficiency, characterized by thrombocyto- penia with small-sized platelets, life-threatening infections, eczema, autoimmunity and increased risk of malignancies. The S125 Abstracts