S134 Abstracts

Ongoing studies are confirming these U87 results using otherGBM cell lines and primary GBM samples.

doi:10.1016/j.clim.2010.03.403

S.83. STAT1:STAT3 Cross-regulation in Patientswith Defective Interferon Gamma SignalingHannelore Bax, Ervand Kristosturyan, Sarah Browne, LiDing, Steven Holland, Elizabeth Sampaio. NIAID/NIH,Bethesda, MD

Mendelian susceptibility tomycobacterial disease (MSMD) ischaracterized by a predisposition to intracellular pathogenswith low virulence such as environmental non-tuberculousmycobacteria and Bacillus Calmette-Guerin in patientswith noovert immunodeficiency. Patients with mutations in the genesencoding the interferon gamma receptor (IFN γR) as well assignal transducer and activator of transcription (STAT)1 belongto this group of rare congenital disorders and these patientsoften present with extensive and therapy resistant mycobac-terial infections. STAT1 is a major component of the IFN γpathway. STAT3, which is predominantly activated by inter-feron alpha (IFN α), is known for opposing the biologicalfunctions of STAT1. It is proposed that the cross-talk betweenSTAT1 and STAT3 is a major factor influencing STAT1dependent gene activation. By Western blot, co-immunopre-cipitation and RT-PCR in peripheral blood mononuclear cells(PBMCs) and EBV-transformed B cells from various patientswith IFN γR or STAT1 deficiencies, the differences in IFNγ andIFN α response were evaluated. All patients but one showedincreased gene expression in response to IFN α associated ornot with increased STAT1 phosphorylation and associated withenhanced STAT3 activation. Further understanding of theimmune responses in those patients is crucial as it might helpproviding new therapeutic strategies.

doi:10.1016/j.clim.2010.03.404

S.84. CNS-infiltrating Vγ4+ γδ T Cells Produce HighLevels of IL-17 and Appear to ContributeSignificantly to the Pathogenesis of the SJLRelapsing EAE Model of Multiple SclerosisStephen Miller, Matthew Caldis, Sarah Blink Polakow.Feinberg School of Medicine, Northwestern University,Chicago, IL

γδ T cells have been identified at key sites of inflamma-tion in autoimmune diseases such arthritis and multiplesclerosis (MS), although their roles in disease pathogenesisand/or protection are not clearly defined. γδ T cells withinthe CSF and lesions of MS patients indicate a limitedrepertoire however the mechanisms for selective recruit-ment and function at the site are not well understood. As animmediate source of cytokines, chemokines and otherfunctions which influence adaptive immunity and whoseresponse is not delayed by obligatory clonal expansion or denovo differentiation, it is clear these cells regulate autoim-mune inflammation in the CNS. Using the SJL PLP139-151-

induced relapsing-remitting EAE (R-EAE) model of MS, wehave identified two distinct subtypes of γδ T cells in the CNSwhose presence and numbers in the cerebellum and spinalcord correlates with severity of disease during the relapsingand remitting stages. Further characterization of Vγ1+and Vγ4+ subsets indicate distinct cytokine profiles. Inter-estingly, the Vγ4+ subset produces more pro-inflammatorymediators such as IL-17 on a per cell basis compared to theVγ1+ subset or CD4+ αβ T cells. In contrast, the Vγ1+ subsetproduces large amounts of IL-10. Preliminary work targetingthese subtypes during EAE results in opposing effects ondisease severity, suggesting both a pathogenic and protec-tive subtype within the CNS infiltrating γδ T cell population.We are currently examining the transcriptional regulation ofIL-17 in the Vγ4+ T cell subset. (Supported grants from theNMSS and the Myelin Repair Foundation).

doi:10.1016/j.clim.2010.03.405

S.85. Regulation of Human CD8 T Cells by IL-27Akanksha Mittal, Murugaiyan Gopal, Howard Weiner.Harvard Medical School, Boston, MA

IL-27 is an anti-inflammatory cytokine that is known toinduce IL-10 producing regulatory T cells in both mice andhuman CD4 T cells. It is also known to induce IFN-γ from CD4 Tcells. In mice CD8 T cells it has been shown that IL-27 inducesIFN-γ producing T cells with increased Granzyme B and Tbetexpression. However how IL-27 influences human CD8 T cellsis not known. We studied how IL-27 affects human CD8 T cellsand found that IL-27 induces IFN-g and IL-10 producing cells,single positive as well as double positive. CD8 T cells treatedwith IL-27 induce high amounts of the transcription factor T-βhowever did not affect other analyzed transcription factors.IL-27 also induces high amounts of the cytotoxic moleculeGranzyme B without affecting perforin and granzyme A. Wefound that IL-27 also induces high amounts of the cytokine IL-21 and its surface receptor IL-21R. We are currently engagedin determining how IL-27 directed secretion of IL-10 andGranzyme-B may be dependent on IL-21. Functionally we arestudying how these IL-27 conditioned CD8 T cells may play aregulatory role by utilizing the upregulated IL-10 or Gran-zyme B. These data will be presented.

doi:10.1016/j.clim.2010.03.406

S.86. Autoreactive T Cells Escaping Thymic Deletionin REL-B Deficient Mice Depend on DendriticCell-encoded REL-B for Control of AutoimmunityBrendan O' Sullivan1, Saparna Pai1, Shayna Street1, KelliMacDonald2, Steve Gerondakis3, Geoffrey Hill2, RanjenyThomas1. 1University of Queensland-Brisbane, Queensland,Australia; 2Queensland Institute of Medical Research,Queensland, Australia; 3Burnet Institute, Victoria, Australia

In humans and mice, autoimmunity is associated withmutations that attenuate T cell receptor (TCR) signalingcapacity, which alter thymic selection, and signaling of theperipheral T cell repertoire. The RelB transcription factor