S95Abstracts

The mechanism by which VAF347 imparts its regulatoryactivity in mouse is partly attributed to the expansion ofFoxP3-expressing regulatory T cell (FoxP3-Treg) that occursthrough an unknown mechanism. In the present study, wedetermined that culture of naïve CD4+ T cells in the presenceof VAF347 has no direct effect on FoxP3 expression underFoxP3-polarinzing conditions. Since dendritic cells (DC)express AHR and are potent stimulators of T cells that caninduce FoxP3-induction, we reasoned to evaluate whetherthe increased frequency of FoxP3-Treg is a result of VAF347modulated DC. Toward this aim, bone marrow derived DCwere treated with varying concentrations of VAF347, pulsedwith OVA 323-339 and exposed to purified, naïve OT-II CD4+ Tcells. After three days of co-culture, FoxP3 expression in OT-II cells occurred in a dose-dependent manner whereby DCcultured with the greatest concentration of VAF347 inducedthe highest percentage of FoxP3+ T cells (approximatelythree-fold greater than untreated). Accordingly, the amountof proliferating OT-II responding cells was also reduced in adose-dependent fashion. Taken together, this data suggeststhat VAF347 can act indirectly to promote FoxP3-inductionwhereby VAF347 can promote the tolerogenic properties ofDC to induce the prevalence of FoxP3-Treg.

doi:10.1016/j.clim.2010.03.284

F.63. Evaluation of Biologics for Autoimmunity inMurine T Cell Dependent Delayed-typeHypersensitivity (DTH) Reaction to MethylatedBovine Serum Albumin (mBSA)Anneline Nansen, Helle Markholst, Claus Haase. NovoNordisk A/S, Maaloev, Denmark

The mBSA-induced DTH reaction is a T cell-mediatedimmune reaction that develops in two phases: in thesensitization phase, T cells are sensitized and antigen-specific effector T cells are formed. Next, in the elicitationphase, recall responses of these T cells are induced uponsecondary challenge with antigen. The effector T cellsrelease cytokines, including IFN-γ and IL-17 that triggerrecruitment of inflammatory cells such as neutrophils andmacrophages. The inflammatory response reaches a maxi-mum at 24 hrs. The advantages of the model are that it isshort (7 days + 1-2 days), highly reproducible and dependenton an antigen-specific T cell immune response. Moreover,the DTH reaction is only seen in the challenged footpad anddraining LN, thus the contra-lateral, PBS-challenged footpadand draining LN serve as an intra-animal control. This site-directed and local reaction makes the model well suited formode of action (MoA) studies of drugs that interfere with orblock T cell priming, cell-migration or inflammatory cyto-kines. We will present data on our robust mBSA-inducedmouse DTH model which we validated using referencecompounds of relevance for the treatment of RA e.g.etanercept (hTNFR2-Ig) and abatacept (hCTLA-4-Ig). MoAwas confirmed by functional ex vivo analyses of footpadexudate cells and popliteal LN following challenge. Ourresults underscore the relevance of DTH models in the

evaluation of biologic drug candidates of relevance to thetreatment of autoimmune diseases.

doi:10.1016/j.clim.2010.03.285

F.64. The CD4+CD25- Adoptive Transfer ColitisModel: A Tool to Evaluate ImmunosuppressiveTherapies in IBDThomas Holm, Helle Markholst, Stine Kjellev. Novo Nordisk,Maaloev, Denmark

Background: Several animal models are used as screeningtools for the development of new and better drugs in IBD.The translational value of a given model is difficult to predictwithout extensive analysis of the experimental system andthe underlying drivers of disease. Objective: The purpose ofthis study was to evaluate the effect of currently used IBDdrugs and IBD drug candidates i.e. TNFR-Fc, anti-TNF-α,corticosteroids, flouroqinolones, cyclosporin, anti-IL-12p40,anti-α4β7 integrin, CTLA-4-IgFc, anti-IL-6 and Copaxone in acolitis model colitis by transfer of CD25 depleted CD4+ Tcells. Material and methods: 300.000 highly purified CD4+CD25- T cells from Balb/c mice were adoptively transferredto C.B-17 scid mice by i.p. injection. Disease developmentwas examined 3 x week during a 4 week period, previouslydescribed in (Kjellev et al., 2006 Int Immunol). Results: Earlyadministration of either: anti-TNF-α, antibiotics, anti-IL-12p40, anti-α4β7 integrin, CTLA4-IgFc or anti-IL-6 effective-ly prevented the onset of colitis. In contrast, mice treatedwith TNFR-Fc, corticosteroids, cyclosporine, copaxone orcontrol reagents, developed severe colitis. Antibiotics, anti-IL-12p40 and CTLA-4-IgFc reversed established colitis,whereas anti-TNF-α and anti-α4β7 integrin did not. Knowingthe advantages and limitations of this model may provideimportant knowledge for future efficacy and mode of actionstudies. Moreover, the finding that several well establishedIBD therapeutics, did not show efficacy in this model,stresses the need for a better understanding of diseasepathways and drivers in experimental colitis models ingeneral.

doi:10.1016/j.clim.2010.03.286

F.65. Successful Outcomes Following MatchedUnrealted Donor BMT for Wiskott Aldrich SyndromeChu Ri Shin, Mi Ok Kim, Alexandra Filipovich. CincinnatiChildren's Hospital and Medical Center, Cincinnati, OH

Introduction: Wiskott-Aldrich Syndrome (WAS), once afatal disorder, is now successfully treated with bonemarrow transplantation (BMT). However matched unrelateddonor (MUD) transplantation remains controversial due tohistorically poorer outcomes. Methods: We retrospectivelyanalyzed outcomes following BMT for 47 WAS patientstreated at our institution from the time period of 1990 to2009. Patients were divided into 2 cohorts based on timing