The regulatory T (Treg) cells restrain immune responses through suppressor-function elaboration that is dependent upon expression of the transcription factor Foxp3. Despite a critical role for Treg cells in maintaining lympho-myeloid homeostasis, it remains unclear whether a single mechanism or multiple mechanisms of Treg cell-mediated suppression are operating in vivo and how redundant such mechanisms might be. Here we addressed these questions by examining the role of the immunomodulatory cytokine IL-10 in Treg cell-mediated suppression. Analyses of mice in which the Treg cell-specific ablation of a conditional IL-10 allele was induced by Cre recombinase knocked into the Foxp3 gene locus showed that although IL-10 production by Treg cells was not required for the control of systemic autoimmunity, it was essential for keeping immune responses in check at environmental interfaces such as the colon and lungs. Our study suggests that Treg cells utilize multiple means to limit immune responses. Furthermore, these mechanisms are likely to be nonredundant, in that a distinct suppressor mechanism most likely plays a prominent and identifiable role at a particular tissue and inflammatory setting.

Relapse after allogeneic hematopoietic cell transplantation (HCT) is the leading cause of death in acute myeloid leukemia (AML) patients entering HCT with poor-risk features. 1-3 When HCT does produce prolonged relapse-free survival (RFS), it commonly reflects graft-versus-leukemia (GVL) effects mediated by donor T cells reactive with antigens on leukemic cells. 4 As graft T cells have not been selected for leukemia-specificity and frequently recognize proteins expressed by many normal host tissues, GVL is often accompanied by morbidity and mortality from graft-versus-host disease (GVHD). 5 Thus, AML relapse risk might be more effectively reduced with T cells expressing receptors (TCRs) that target selected AML antigens. 6 We therefore isolated a high

Arachidonic acid metabolites, the eicosanoids, are key mediators of allergen-induced airway inflammation and remodeling in asthma. The availability of free arachidonate in cells for subsequent eicosanoid biosynthesis is controlled by phospholipase A2s (PLA2s), most notably cytosolic PLA2-α. 10 secreted PLA2s (sPLA2s) have also been identified, but their function in eicosanoid generation is poorly understood. We investigated the role of group X sPLA2 (sPLA2-X), the sPLA2 with the highest in vitro cellular phospholipolysis activity, in acute and chronic mouse asthma models in vivo. The lungs of sPLA2-X−/− mice, compared with those of sPLA2-X+/+ littermates, had significant reduction in ovalbumin-induced infiltration by CD4+ and CD8+ T cells and eosinophils, goblet cell metaplasia, smooth muscle cell layer thickening, subepithelial fibrosis, and levels of T helper type 2 cell cytokines and eicosanoids. These data direct attention to sPLA2-X as a novel therapeutic target for asthma.

Summary Multiple sclerosis (MS) is a disease of the central nervous system (CNS) characterized by inflammatory, demyelinating lesions localized in the brain and spinal cord. Experimental autoimmune encephalomyelitis (EAE) is an animal model of MS that is induced by activating myelin-specific T cells and exhibits immune cell infiltrates in the CNS similar to those seen in MS. Both MS and EAE exhibit disease heterogeneity, reflecting variations in clinical course and localization of lesions within the CNS. Collectively, the differences seen in MS and EAE suggest that the brain and spinal cord function as unique microenvironments that respond differently to infiltrating immune cells. This review addresses the roles of the cytokines interferon-γ and interleukin-17 in determining the localization of inflammation to the brain or spinal cord in EAE.

Objective. To test the association of osteopontin (OPN) polymorphisms with systemic lupus erythematosus (SLE).Methods. . These effects were independent of each other, i.e., not a consequence of linkage disequilibrium between the 2 alleles. The risk associated with a double dose of susceptibility alleles at both SNPs was 3.8-fold higher (95% CI 2.0-7.4) relative to the complete absence of susceptibility alleles. With regard to individual clinical and immunologic features, a significant association was seen between lymphadenopathy and ؊156 genotypes (overall P ‫؍‬ 0.0011, P corr ‫؍‬ 0.046). A significantly increased OPN serum level was detected in healthy individuals carrying ؉1239C (P ‫؍‬ 0.002), which is indicative of an association between the SLE susceptibility allele and OPN levels. Conclusion. These data suggest the independent effect of a promoter (؊156) and a 3 -untranslated region (؉1239) SNP in SLE susceptibility. We can speculate that these sequence variants (or others in perfect linkage disequilibrium) create a predisposition to high production of OPN, and that this in turn may confer susceptibility to SLE.Systemic lupus erythematosus (SLE) is an autoimmune disease with a multifactorial etiology that is characterized by impaired T cell responses and dysregulation of B cell activation, leading to B cell hyperactivity and production of autoantibodies. Several lines of evi-