Cytokine-Like 1 Is a Novel Proangiogenic Factor Secreted by and Mediating Functions of Endothelial Progenitor Cells.

Rationale: Endothelial colony forming cells (ECFCs) or late blood outgrowth endothelial cells can be isolated from human cord or peripheral blood, display properties of endothelial progenitors, home into ischemic tissues and support neovascularization in ischemic disease models.

Objective: To assess the functions of CYTL1 (cytokine-like 1), a factor we found preferentially produced by ECFCs, in regard of vessel formation.

Methods And Results: We show by transcriptomic analysis that ECFCs are distinguished from endothelial cells of the vessel wall by production of high amounts of CYTL1.

Lactoferrin is a natural inhibitor of plasminogen activation.

The plasminogen system is essential for dissolution of fibrin clots, and in addition, it is involved in a wide variety of other physiological processes, including proteolytic activation of growth factors, cell migration, and removal of protein aggregates. On the other hand, uncontrolled plasminogen activation contributes to many pathological processes ( tumor cells' invasion in cancer progression). Moreover, some virulent bacterial species ( or ) bind human plasminogen and hijack the host's plasminogen system to penetrate tissue barriers.

Quantification of human diamine oxidase.

Objectives: Diamine oxidase (DAO) is essential for extracellular degradation of histamine. For decades activity assays with inherent limitations were used to quantify the relative amounts of DAO. No reference DAO standard is available.

Human cytomegalovirus phosphoproteins are hypophosphorylated and intrinsically disordered.

Protein phosphorylation has important regulatory functions in cell homeostasis and is tightly regulated by kinases and phosphatases. The tegument of human cytomegalovirus (CMV) contains not only several proteins reported to be extensively phosphorylated but also cellular protein phosphatases (PP1 and PP2A). To investigate this apparent inconsistency, we evaluated the phosphorylation status of the tegument proteins pUL32 and pp65 by enzymatic dephosphorylation and MS.

The soluble cytoplasmic tail of CD45 (ct-CD45) in human plasma contributes to keep T cells in a quiescent state.

The cytoplasmic tail of CD45 (ct-CD45) is proteolytically cleaved and released upon activation of human phagocytes. It acts on T cells as an inhibitory, cytokine-like factor in vitro. Here, we show that ct-CD45 is abundant in human peripheral blood plasma from healthy adults compared with plasma derived from umbilical cord blood and plasma from patients with rheumatoid arthritis or systemic lupus erythematosus.

Novel immune assay for quantification of plasma protective capacity against oxidized phospholipids.

Aim: Oxidized phospholipids (OxPL) are the major pathogenic component of oxidized low-density lipoproteins (OxLDL). Endogenous anti-OxPL activity, defined as the ability to neutralize adverse effects of oxidized lipids, may have biomarker potential.

Methods & Results: Using two anti-OxPL monoclonal antibodies (commercial mAB-E06 and custom mAB-509) we developed a novel ELISA that measures the global capacity of plasma to inactivate OxPL.

Engagement of distinct epitopes on CD43 induces different co-stimulatory pathways in human T cells.

Co-receptors, being either co-stimulatory or co-inhibitory, play a pivotal role in T-cell immunity. Several studies have indicated that CD43, one of the abundant T-cell surface glycoproteins, acts not only as a potent co-receptor but also as a negative regulator for T-cell activation. Here we demonstrate that co-stimulation of human peripheral blood (PB) T cells through two distinct CD43 epitopes recognized by monoclonal antibodies (mAb) CD43-6E5 (T ) and CD43-10G7 (T ) potently induced T-cell proliferation.

Assessment of costimulation and coinhibition in a triple parameter T cell reporter line: Simultaneous measurement of NF-κB, NFAT and AP-1.

Engagement of the T cell receptor complex reprograms T cells for proliferation, cytokine production and differentiation towards effector cells. This process depends on activating costimulatory signals and is counteracted by coinhibitory molecules. Three transcription factors, namely NF-κB, NFAT and AP-1, have a major role in inducing the transcriptional program that is required for T cell activation and differentiation.

Establishment and characterization of a primary and a metastatic melanoma cell line from Grey horses.

The Grey horse phenotype, caused by a 4.6 kb duplication in Syntaxin 17, is strongly associated with high incidence of melanoma. In contrast to most human melanomas with an early onset of metastasis, the Grey horse melanomas have an extended period of benign growth, after which 50% or more eventually undergo progression and may metastasize.

Human Langerhans cells control Th cells via programmed death-ligand 1 in response to bacterial stimuli and nickel-induced contact allergy.

Langerhans cells (LCs) are suspected to initiate inflammatory immune responses to contact allergens and pathogenic bacteria. In chronic infectious diseases, programmed death ligand (PD-L) 1 exhibits both inhibitory and costimulatory functions on T cell-mediated activation and tolerance. Here, we investigated the effects of contact allergens and bacterial stimuli on PD-L1 expression in LCs and the effects of altered PD-L1 expression on cytokine release of subsequently cocultured T cells.

Assessment of batch to batch variation in polyclonal antithymocyte globulin preparations.

Background: Antithymocyte globulins (ATGs) are used to prevent and treat allograft rejection and graft versus host disease. They are purified IgG fractions derived from rabbits immunized with the Jurkat T-cell line (ATG-Fresenius) or thymus cells (Thymoglobulin). Differences not only in the amounts of leukocyte reactive antibodies but also in the antigens targeted by ATGs could potentially affect the clinical efficacy of different batches of these polyclonal antibody preparations.

The effects of Cyclosporine A and azathioprine on human T cells activated by different costimulatory signals.

Immunosuppression is an important treatment modality in transplantation and human diseases that are associated with aberrant T cell activation. There are considerable differences regarding the cellular processes targeted by the immunosuppressive drugs that are in clinical use. Drugs like azathioprine (Aza) mainly act by halting proliferation of fast dividing cells, whereas others like cyclosporine A (CsA) specifically target signaling pathways in T cells.

Mapping of conformational IgE epitopes with peptide-specific monoclonal antibodies reveals simultaneous binding of different IgE antibodies to a surface patch on the major birch pollen allergen, Bet v 1.

Allergic inflammation is based on the cross-linking of mast cell and basophil-bound IgE Abs and requires at least two binding sites for IgE on allergens, which are difficult to characterize because they are often conformational in nature. We studied the IgE recognition of birch pollen allergen Bet v 1, a major allergen for >100 million allergic patients. Monoclonal and polyclonal Abs raised against Bet v 1-derived peptides were used to compete with allergic patients' IgE binding to Bet v 1 to search for sequences involved in IgE recognition.

Costimulatory signals potently modulate the T cell inhibitory capacity of the therapeutic CD11a antibody Efalizumab.

The therapeutic CD11a antibody Efalizumab interferes with psoriasis pathogenesis by blocking T cell activation and migration. We have performed a detailed analysis on its effects during the activation of human T cells and found that the capability of Efalizumab to inhibit proliferation and cytokine production of T cells critically depends on the quality and quantity of costimulatory signals. Efalizumab potently inhibited the proliferation and cytokine production of human T cells costimulated via ICOS, OX40, CD27 or 4-1BB, but did not significantly inhibit T cells that received stimuli via CD2 or CD28.

T cell stimulator cells, an efficient and versatile cellular system to assess the role of costimulatory ligands in the activation of human T cells.

It is well established that full activation of T cells requires the interaction of the TCR complex with the peptide-MHC complex (Signal 1) and additional signals (Signal 2). These second signals are generated by the interaction of costimulatory ligands expressed on antigen presenting cells with activating receptors on T cells. In addition, T cell responses are negatively regulated by inhibitory costimulatory pathways.

Expressional and functional studies of CKLF1 during dendritic cell maturation.

Chemokine-like factor 1 (CKLF1) was the first member of the CKLF-like MARVEL transmembrane domain containing member (CMTM) family to be discovered. Its expression level is increased clearly in peripheral blood lymphocytes upon phytohemagglutinin stimulation, but little is known about the expression and function of CKLF1 in dendritic cells (DCs), which are the most potent antigen-presenting cells. In the present study, we showed that CKLF1 was highly expressed in monocytes.

Human rhinoviruses induce IL-35-producing Treg via induction of B7-H1 (CD274) and sialoadhesin (CD169) on DC.

IL-35 is a heterodimer of EBV-induced gene 3 and of the p35 subunit of IL-12, and recently identified as an inhibitory cytokine produced by natural Treg in mice, but not in humans. Here we demonstrate that DC activated by human rhinoviruses (R-DC) induce IL-35 production and release, as well as a suppressor function in CD4(+) and CD8(+) T cells derived from human peripheral blood but not in naïve T cells from cord blood. The induction of IL-35-producing T cells by R-DC was FOXP3-independent, but blocking of B7-H1 (CD274) and sialoadhesin (CD169) on R-DC with mAb against both receptors prevented the induction of IL-35.

Epigenetic regulation of dendritic cell differentiation and function by oxidized phospholipids.

Dendritic cells (DCs) are the key cell type in the regulation of an adaptive immune response. Under inflammatory conditions monocytes can give rise to immunostimulatory DCs, depending on microenvironmental stimuli. Here we show that oxidized phospholipids (Ox-Pls), which are generated during inflammatory reactions, dysregulate the differentiation of DCs.

The ssRNA genome of human rhinovirus induces a type I IFN response but fails to induce maturation in human monocyte-derived dendritic cells.

Dendritic cells (DCs) use pattern recognition receptors to sense invading viruses and triggering of these receptors induces a maturation program. Human rhinoviruses (HRVs) belong to the family of Picornaviridae, which have a single-stranded, coding RNA genome. Because HRV does not replicate in DCs, we used genomic RNA from HRV in this study to analyze the impact of natural occurring viral ssRNA on DC function.

Allogeneic disparities in immunoglobulin-like transcript 5 induce potent antibody responses in hematopoietic stem cell transplant recipients.

In hematopoietic stem cell transplant (HSCT) recipients, the recognition of polymorphic antigens by the donor-derived immune system is an important mechanism underlying both graft-versus-host disease and graft-versus-leukemia (GVL) effect. Here we show that a subset of HSCT recipients (13.9%, n = 108) have antibodies directed to surface molecules of dendritic cells.

B7-H3 is a potent inhibitor of human T-cell activation: No evidence for B7-H3 and TREML2 interaction.

B7-H3 belongs to the B7 superfamily, a group of molecules that costimulate or down-modulate T-cell responses. Although it was shown that B7-H3 could inhibit T-cell responses, several studies - most of them performed in murine systems - found B7-H3 to act in a costimulatory manner. In this study, we have specifically addressed a potential functional dualism of human B7-H3 by assessing the effect of this molecule under varying experimental conditions as well as on different T-cell subsets.

The capacity of the TNF family members 4-1BBL, OX40L, CD70, GITRL, CD30L and LIGHT to costimulate human T cells.

Activating signals generated by members of the tumour necrosis factor receptor superfamily upon interaction with their cognate ligands play important roles in T-cell responses. Members of the tumour necrosis factor family namely 4-1BBL, OX40L, CD70, GITRL, LIGHT and CD30L have been described to function as costimulatory molecules by binding such receptors on T cells. Using our recently described system of T-cell stimulator cells we have performed the first study where all these molecules have been assessed and compared regarding their capacity to costimulate proliferation and cytokine production of human T cells.

The oxidation state of phospholipids controls the oxidative burst in neutrophil granulocytes.

The activation of neutrophil granulocytes has to be carefully controlled to balance desired activity against invading pathogens while avoiding overwhelming activation leading to host tissue damage. We now show that phospholipids are potential key players in this process by either enhancing or dampening the production of reactive oxygen species (ROS) during the oxidative burst. Unoxidized phospholipids induce the production of ROS, and they also work synergistically with FMLP in potentiating the oxidative burst in neutrophil granulocytes.

Localization and characterization of the novel protein encoded by C20orf3.

In the present study, we characterized the gene product of open reading frame 3 encoded at human chromosome 20 (C20orf3), which represents a member of the lactonohydrolase super family. Multiple-tissue Northern blot analysis showed ubiquitous expression of the 2.4 kb transcript coding for 416 amino acids, with highest levels in human liver, placenta and kidney.

The cytoplasmic tail of CD45 is released from activated phagocytes and can act as an inhibitory messenger for T cells.

CD45 is the prototypic transmembrane protein tyrosine phosphatase (PTP), which is expressed on all nucleated hematopoietic cells and plays a central role in the integration of environmental signals into immune cell responses. Here we report an alternative function for the intracellular domain of CD45. We dis-covered that CD45 is sequentially cleaved by serine/metalloproteinases and gamma-secretases during activation of human monocytes and granulocytes by fungal stimuli or phorbol 12-myristate 13-acetate but not by other microbial stimuli.