Interleukin-7 (IL-7) is essential for T cell development in the thymus and maintenance of peripheral T cells. The α-chain of the IL-7R is polymorphic with the existence of SNPs that give rise to nonsynonymous amino acid substitutions. We previously found an association between donor genotypes and increased treatment related mortality (TRM) (rs1494555G) and acute graft versus host disease (aGvHD) (rs1494555G and rs1494558T) after hematopoietic cell transplantation (HCT). Some studies have confirmed an association between rs6897932C and multiple sclerosis. In the present study we evaluated the prognostic significance of IL-7Rα SNP genotypes in 590- recipient/donor pairs that received HLA matched unrelated donor HCT for hematological malignancies. Consistent with the primary studies, the rs1494555GG and rs1494558TT genotypes of the donor were associated with aGvHD and chronic GvHD in the univariate analysis. The T allele of rs6897932 was suggestive of an association with increased frequency of relapse by univariate analysis (p=0.017) and multivariate analysis (p=0.015). In conclusion, this study provides further evidence of a role of the IL-7 pathway and IL-7Rα SNPs in HCT. This article is protected by copyright. All rights reserved.

Sjögren's syndrome (SjS), an autoimmune disease characterized by exocrine gland dysfunction leading to dry mouth and dry eye diseases, is typified by progressive leukocyte infiltrations of the salivary and lacrimal glands. Histologically, these leukocyte infiltrations generally establish peri-ductal aggregates, referred to as lymphocytic foci (LF), that occassionally appear as germinal center-like structures. The formation and organization of these LF suggest an important and dynamic role for helper T cells (TH), specifically TH1, TH2 and the recently discovered TH17, in development and onset of clinical SjS, considered a B cell-mediated hypersensitivity type 2 disease. Despite an ever-increasing focus on identifying the underlying etiology of SjS, defining factors that initiate this autoimmune disease remains a mystery. Thus, determining interactions between infiltrating TH cells and exocrine gland tissue (auto-)antigens represents a fertile research endeavor. This review discusses pathological functions of TH cells in SjS, the current status of TH cell receptor gene rearrangements associated with human and mouse models of SjS, and potential future prospects for identifying receptor-autoantigen interactions. This article is protected by copyright. All rights reserved.

Reactive oxygen species (ROS) are produced by dendritic cells (DCs) during antigen presentation in contact hypersensitivity (CHS). ROS cause a number of non-enzymatic protein modifications, such as carbonylation. Carbonylated proteins in DCs in response to hapten have not been fully identified yet. To identify the proteins carbonylated by ROS, murine epidermis-derived dendritic cell line XS106 was challenged with a hapten, 2,4,6-trinitrobenzene sulfonic acid (TNBS). MALDI-TOF analysis revealed that heat shock protein 70 (HSP70) was one of the carbonylated proteins induced by TNBS. To verify the role of HSP70 in TNBS-treated XS106 cell, we fused protein transduction domain (PTD) to HSP70 to facilitate protein delivery into the cell. The transfected fusion protein PTD-HSP70 caused transient increase of the cellular level of HSP70. Transient increase of HSP70 level in XS-106 DCs resulted in inhibition of ROS production, carbonylation of HSP70, p38 MAPK activation, and subsequently IL-12 secretion. To investigate the effects of PTD-HSP70 in vivo, ear swelling experiments with 2,4,6-trinitro-1-chlorobenzene (TNCB) were performed in BALB/c mice. Pretreatment of PTD-HSP70 reduced the CHS response to TNCB in vivo. We report here that carbonylation of HSP70 by ROS is associated with the pathogenesis of CHS, suggesting possibility of HSP70-targeting therapy in CHS. This article is protected by copyright. All rights reserved.

BACKGROUND:

Microparticles (MPs) are small membrane-bound vesicles that arise from activated and dying cells and promote inflammation and thrombosis. To characterize the in vivo release of MPs, we used flow cytometry to measure MPs in the blood of 15 healthy volunteers administered bacterial endotoxin (lipopolysaccharide or LPS) in the presence of a low dose of hydrocortisone with or without inhaled nitric oxide.

METHODS:

MPs, defined as particles less than 1.0 μm in size, were assessed following labeling for CD42a, CD14, and CD62E or CD144 antibodies to identify MPs from platelets (PMPs), monocytes (MMPs) and endothelial cells (EMPs). In addition, PMPs and MMPs were labeled with anti-HMGB1 and stained with SYTO13 to assess nuclear acid content.

RESULTS:

Administration of LPS led to an increase in the numbers of PMPs, MMPs, and EMPs as defined by CD62E, as well as the number of MMPs and PMPs staining with anti-HMGB1 and SYTO13. Inhalation of NO did not influence these findings.

CONCLUSIONS:

Together, these studies show that LPS can increase levels of blood MPs and influence phenotype, including nuclear content. As such, particles may be a source of HMGB1 and other nuclear molecules in the blood during inflammation. This article is protected by copyright. All rights reserved.

Wnt5a is a non-canonical Wnt protein that is expressed at elevated levels in inflammatory conditions. Its role in inflammation remains unclear, although it is known that Wnt5a is expressed at a higher level in monocyte-derived myeloid dendritic cells (Mo-mDCs) than in monocytes and macrophages. The function of Wnt5a in dendritic cells (DCs) remains relatively unexplored. Here, we found that under Mo-mDC culture conditions, Wnt5a inhibited the generation of CD14(+/low) Mo-mDCs while promoting the generation of CD14(+/++) CD16(+) monocytes. We could further show that stimulation of monocytes with rWnt5a induced a rapid IL-6 production and that the rWnt5a treated Mo-mDC differentiation was restored upon blocking of IL-6. Also conditioned media from Wnt5a stimulated human breast cancer cells producing IL-6, specifically inhibited Mo-mDC differentiation. These observations are strengthened by our finding that patients with sepsis, a disease involving elevated Wnt5a and IL-6 levels, also showed a significant increase in the CD14(+) CD16(++) /CD14(+/++) CD16(+) monocyte populations, which was accompanied by a significant decrease in circulating mDCs. We finally show that under typical Mo-mDC culture conditions, monocytes isolated from sepsis patients as compared to healthy controls, preferentially differentiated into CD14(+/++) HLA-DR(++) cells. We suggest that Wnt5a is a possible candidate mediator for the CD14(+/++) CD16(+) monocyte accumulation seen in infectious disease and cancer patients. This article is protected by copyright. All rights reserved.

In this study, we hypothesized that the mice immunized with the glycosylphosphatidylinositol (GPI) anchored 6 kDa early-secreted antigenic target (ESAT-6) DNA vaccine (ESAT-6-gpi) and the tumor vaccine B16F10-ESAT-6- gpi/IL-21 might significantly enhance immune responses and antimelanoma efficacy. Our experimental results indicated that the anti-ESAT-6 antibody induced by the DNA vaccine ESAT-6-gpi bound ESAT-6 to the surface of tumor vaccine to activate a complement classical pathway and resulted in the B16F10 tumor cell lysis and apoptosis, which served as a potential potent trigger for breaking melanomatous immune tolerance to elicit an initiation of natural anti- melanoma immunity. Our innovative approach of using the DNA vaccine ESAT-6-gpi priming and the tumor vaccine B16F10-ESAT-6-gpi/IL-21 boosting induced strong antimelanoma immunity that inhibited melanomatous growth. These findings highlighted the DNA vaccine ESAT-6-gpi as an immune-enhancer to augment the immune efficacy of the tumor vaccine B16F10-ESAT-6-gpi/IL-21 against melanoma in a mouse model. This article is protected by copyright. All rights reserved.

One of the principles behind vaccination, as shown by Edward Jenner in 1796, and host protection is immunological memory, and one of the cells central to this is the antigen-experienced memory B cell that responds rapidly upon re-exposure to the initiating antigen. Classically, memory B cells have been defined as progenies of germinal center (GC) B cells expressing isotype-switched and substantially mutated B cell receptors (BCRs), i.e. membrane bound antibodies. However, it has become apparent over the last decade that this is not the only pathway to B cell memory. Here, we will discuss memory B cells in mice, as defined by (i) cell surface markers, (ii) multiple layers, (iii) formation in a T cell-dependent and either GC-dependent or -independent manner; (iv) formation in a T cell-independent fashion. Lastly, we will touch upon memory B cells in (v) mouse models of autoimmune diseases. This article is protected by copyright. All rights reserved.

The activating Natural Killer Group 2 member D (NKG2D) receptor is expressed on NK cells, cytotoxic T cells and additional T cell subsets. Ligands for human NKG2D comprise two groups of MHC class I-related molecules, the MHC class I chain-related proteins A and B (MICA/B) and 6 UL16-binding proteins (ULBP1-6). While NKG2D ligands are absent from most normal cells, expression is induced upon stress and malignant transformation. In fact, most solid tumors and leukemias/lymphomas constitutively express at least one NKG2D ligand and thereby are susceptible to NKG2D-dependent immunosurveillance. However, soluble NKG2D ligands are released from tumor cells and can down-modulate NKG2D activation as a means of tumor immune escape. In some tumor entities, levels of soluble NKG2D ligands in the serum correlate with tumor progression. NKG2D ligands can be proteolytically shed from the cell surface or liberated from the membrane by phospholipase C in the case of glycosylphosphatidylinositol (GPI)-anchored molecules. Moreover, NKG2D ligands can be secreted in exosomal microvesicles together with other tumor-derived molecules. Depending on the specific tumor/immune cell setting, these various forms of soluble and/or exosome-bound NKG2D ligands can exert multiple effects on NKG2D/NKG2D ligand interactions. In this review we focus on the role of various proteases in the shedding of human NKG2D ligands from tumor cells and discuss the not completely unanimous reported functional implications of soluble and exosome-secreted NKG2D ligands for immunosurveillance. This article is protected by copyright. All rights reserved.

Current knowledge of helper T cell differentiation largely relies on data generated from mouse studies. To develop therapeutical strategies combating human diseases, understanding the molecular mechanisms how human naïve T cells differentiate to functionally distinct T helper (Th) subsets as well as studies on human differentiated Th cell subsets are particularly valuable. Systems biology approaches provide a holistic view of the processes of T helper differentiation, enable discovery of new factors and pathways involved and generation of new hypotheses to be tested to improve our understanding of human Th cell differentiation and immune-mediated diseases. Here we summarize studies where high-throughput systems biology approaches have been exploited to human primary T cells. These studies reveal new factors and signaling pathways influencing T cell differentiation towards distinct subsets, important for immune regulation. Such information provides new insights into T cell biology and into targeting immune system for therapeutic interventions. This article is protected by copyright. All rights reserved.

In the context of immunity, pattern-recognition is the art of discriminating friend from foe and innocuous from noxious. The basis of discrimination is the existence of evolutionarily conserved patterns on microorganisms, which are intrinsic to these microorganisms and necessary for their function and existence. Such immutable or slowly evolving patterns are ideal handles for recognition and have been targeted by early cellular immune defense mechanisms such as Toll-like receptors, NOD-like receptors, RIG-I-like receptors, C-type lectin receptors and by humoral defense mechanisms such as the complement system. Complement is a proteolytic cascade system comprising around 35 different soluble and membrane-bound proteins. It constitutes a central part of the innate immune system, mediating several major innate effector functions and modulating adaptive immune responses. The complement cascade proceeds via controlled, limited proteolysis and conformational changes of constituent proteins through three activation pathways: the classical pathway, the alternative pathway, and the lectin pathway, which converge in common effector functions. Here we review the nature of the pattern-recognition molecules involved in complement activation, as well as their close relatives with no or unknown capacity for activating complement. We proceed to examine the composition of the pattern-recognition complexes involved in complement activation, focusing on those of the lectin pathway, and arrive at a new model for their mechanism of operation, supported by recently emerging evidence. This article is protected by copyright. All rights reserved.