Tregs utilize β-galactoside-binding protein to transiently inhibit PI3K/p21 activity of human CD8 T cells to block their TCR-mediated ERK activity and proliferation

Regulatory T cells (Tregs) and beta-galactoside-binding protein (βGBP), a regulatory protein often found expressed at sites of immunological privilege, have similar functions. Their presence affects the outcome of harmful autoimmunity and cancers, including experimental autoimmune encephalomyelitis and malignant gliomas. Here we report a novel pathway by which Tregs express and utilize βGBP to control CD8⁺ T cell responses partially activating TCR signaling but blocking PI3K activity. As a result, this leads to a loss of p21^ras, ERK and Akt activities despite activation of TCR proximal signals, such as phosphorylation of CD3ζ, Zap70, Lat and PKCθ. Although non-processive TCR signaling often leads to cell anergy, Tregs/βGBP did not affect cell viability. Instead, βGBP/Tregs transiently prevented activation of CD8⁺ T cells with self-antigens, while keeping their responses to xenogeneic antigens unaffected.     

Chemokine receptor targeting efficiently directs antigens to MHC class I pathways and elicits antigen-specific CD8+ T-cell responses

Chemokines are key controllers of cell trafficking and are involved in numerous pathologic and inflammatory conditions. However, the fate of a chemokine ligand, once it is endocytosed with its receptor, remains obscure. Here, using chemokine-tumor antigen fusion constructs, we demonstrate for the first time that chemokines are internalized to early/late endosomal and lysosomal compartments through a clathrin-dependent process and subsequently delivered to the cytosol for proteasomal processing, facilitating efficient cross-presentation to the TAP-1-dependent MHC class I processing pathway. These data not only elucidate the intracellular fate of chemokine ligands upon receptor uptake, but also demonstrate the superior carrier potency of chemokines for delivering self-antigens to both class I and II processing pathways to induce CD8(+) and CD4(+) T-cell responses.     

The effects of alcohol consumption,psychological distress and smoking status on emergency department presentations in New South Wales,Australia

Background  

Despite clear links between risky alcohol consumption, mental health problems and smoking with increased morbidity and mortality, there is inconclusive evidence about how these risk factors combine and if they are associated with increased attendance at emergency departments. This paper examines the population-level associations and interactions between alcohol consumption, psychological distress and smoking status with having presented to an emergency department in the last 12 months.     

PKC and PKA Phosphorylation Affect the Subcellular Localization of Claudin-1 in Melanoma Cells

Cytoplasmic expression of claudin-1 in metastatic melanoma cells correlates to increased migration, and increased secretion of MMP-2 in a PKC dependent manner, whereas claudin-1 nuclear expression is found in benign nevi. Melanoma cells were transfected with a vector expressing CLDN-1 fused to a nuclear localization signal (NLS). Despite significant nuclear localization of claudin-1, there was still transport of claudin-1 to the cytoplasm. Phorbol ester treatment of cells transfected with NLS-claudin-1 resulted in an exclusion of claudin-1 from the nucleus, despite the NLS. To ascertain whether PKC or PKA were involved in this translocation, we mutated the putative phosphorylation sites within the protein. We found that mutating the PKC phosphorylation sites to mimic a non-phosphorylated state did not cause a shift of claudin-1 to the nucleus of the cells, but mutating the PKA sites did. Mutations of either site to mimic constitutive phosphorylation resulted in cytoplasmic claudin-1 expression. Stable claudin-1 transfectants containing non-phosphorylatable PKA sites exhibited decreased motility. These data imply that subcellular localization of claudin-1 can be controlled by phosphorylation, dicating effects on metastatic capacity.     

Characteristics of non-fatal opioid overdoses attended by ambulance services in Australia

OBJECTIVE: To examine the feasibility of establishing a database on non-fatal opioid overdose in order to examine patterns and characteristics of these overdoses across Australia. METHODS: Unit record data on opioid overdose attended by ambulances were obtained from ambulance services in the five mainland States of Australia for available periods, along with information on case definition and opioid overdose management within these jurisdictions. Variables common across States were examined including the age and sex of cases attended, the time of day and day of week of the attendance, and the transportation outcome (whether the victim was left at the scene or transported to hospital). RESULTS: The monthly rate of non-fatal opioid overdose attended by ambulance was generally highest in Victoria (Melbourne) followed by NSW, with the rates substantially lower in the remaining States over the period January 1999 to February 2001. Non-fatal opioid overdose victims were most likely to be male in all States, with the proportion of males highest in Victoria (77%), and were aged around 28 years with ages lowest in Western Australia (m=26) and highest in NSW (m=30). Most of the attendances occurred in the afternoon/early evening and towards the later days of the working week in all States. The rates of transportation varied according to ambulance service practice across the States with around 94% of cases transported in Western Australia and around 18% and 29% of cases transported in Melbourne and NSW respectively. CONCLUSIONS: It is feasible to establish a database of comparable data on non-fatal opioid overdoses attended by ambulances in Australia. This compilation represents a useful adjunct to existing surveillance systems on heroin (and other opioid) use and related harms.