Enhancement of tumor immunotherapy by deletion of the A2A adenosine receptor.

The A(2A) adenosine receptor plays a critical and non-redundant role in suppressing inflammation at sites of hypoxia and tissue damage. The tumor microenvironment has high levels of adenosine as a result of hypoxia and ectopic expression of enzymes responsible for the generation of extracellular adenosine. Thus, we sought to determine the ability of A(2A) receptor null mice to immunologically reject tumors.

The mTOR kinase differentially regulates effector and regulatory T cell lineage commitment.

Effector T cell differentiation requires the simultaneous integration of multiple, and sometimes opposing, cytokine signals. We demonstrated mTOR's role in dictating the outcome of T cell fate. mTOR-deficient T cells displayed normal activation and IL-2 production upon initial stimulation.

Opposing regulation of T cell function by Egr-1/NAB2 and Egr-2/Egr-3.

TCR-induced NF-AT activation leads to the up-regulation of multiple genes involved in T cell anergy. Since NF-AT is also involved in T cell activation, we have endeavored to dissect TCR-induced activating and inhibitory genetic programs. This approach revealed roles for the early growth response (Egr) family of transcription factors and the Egr coactivator/corepressor NGFI-A-binding protein (NAB)2 in regulating T cell function.

A2A receptor signaling promotes peripheral tolerance by inducing T-cell anergy and the generation of adaptive regulatory T cells.

Tissue-derived adenosine, acting via the adenosine A(2A) receptor (A(2A)R), is emerging as an important negative regulator of T-cell function. In this report, we demonstrate that A(2A)R stimulation not only inhibits the generation of adaptive effector T cells but also promotes the induction of adaptive regulatory T cells. In vitro, antigen recognition in the setting of A(2A)R engagement induces T-cell anergy, even in the presence of costimulation.

Adenosine and anergy.

T cells must integrate multiple environmental cues when deciding whether to mount an immunogenic or tolerogenic response. Since not all self-reactive T cells are eliminated during thymic development, mechanisms of peripheral tolerance such as T cell anergy contribute to preventing autoimmunity. Recent studies have implicated extracellular adenosine and the adenosine A(2A) receptor as playing an important role in inhibiting T cell effector function.

A role for mammalian target of rapamycin in regulating T cell activation versus anergy.

Whether TCR engagement leads to activation or tolerance is determined by the concomitant delivery of multiple accessory signals, cytokines, and environmental cues. In this study, we demonstrate that the mammalian target of rapamycin (mTOR) integrates these signals and determines the outcome of TCR engagement with regard to activation or anergy. In vitro, Ag recognition in the setting of mTOR activation leads to full immune responses, whereas recognition in the setting of mTOR inhibition results in anergy.

Fragmentation of sialylated carbohydrates using infrared atmospheric pressure MALDI ion trap mass spectrometry from cation-doped liquid matrixes.

Infrared atmospheric pressure matrix-assisted laser desorption/ionization on an ion trap mass spectrometer is used to study sialylated oligosaccharides desorbed from the liquid phase. Glycerol doped with various cations provides the opportunity to produce cation-adducted intact molecular ions of sugars. Distinct combinations of cations allow for sialic acid stabilization, as well as differential cleavage, resulting in more complete fragmentation coverage of the oligosaccharide.

Prolonged kappa opioid receptor phosphorylation mediated by G-protein receptor kinase underlies sustained analgesic tolerance.

Kappa opioid receptor (KOR) desensitization was previously shown to follow agonist-dependent phosphorylation of serine 369 by G-protein receptor kinase (GRK) and beta-arrestin binding in transfected cells. To study the in vivo effects induced by phosphorylation of KOR(S369), C57Bl/6 mice were administered single or repeated doses of the KOR agonist, U50,488, and isolated brain glycoprotein was probed with an antibody, KOR-P, that specifically recognized phosphoserine 369 KOR. Western blot analysis using KOR-P antibody showed that labeling intensity increased after either single or repeated treatment of mice with U50,488 by 59 +/- 22% and 101 +/- 29%, respectively.