Compartmentalization of total and virus-specific tissue-resident memory CD8+ T Cells in human lymphoid organs

Disruption of T cell memory during severe immune suppression results in reactivation of chronic viral infections, such as Epstein Barr virus (EBV) and Cytomegalovirus (CMV). How different subsets of memory T cells contribute to the protective immunity against these viruses remains poorly defined. In this study we examined the compartmentalization of virus-specific, tissue resident memory CD8+ T cells in human lymphoid organs. This revealed two distinct populations of memory CD8+ T cells, that were CD69+CD103+ and CD69+CD103-, and were retained within the spleen and tonsils in the absence of recent T cell stimulation. These two types of memory cells were distinct not only in their phenotype and transcriptional profile, but also in their anatomical localization within tonsils and spleen. The EBV-specific, but not CMV-specific, CD8+ memory T cells preferentially accumulated in the tonsils and acquired a phenotype that ensured their retention at the epithelial sites where EBV replicates. In vitro studies revealed that the cytokine IL-15 can potentiate the retention of circulating effector memory CD8+ T cells by down-regulating the expression of sphingosine-1-phosphate receptor, required for T cell exit from tissues, and its transcriptional activator, Kruppel-like factor 2 (KLF2). Within the tonsils the expression of IL-15 was detected in regions where CD8+ T cells localized, further supporting a role for this cytokine in T cell retention. Together this study provides evidence for the compartmentalization of distinct types of resident memory T cells that could contribute to the long-term protection against persisting viral infections

A Review of Boron Neutron Capture Therapy: Its History and Current Challenges

MECHANISM OF ACTION: External beam, whether with photons or particles, remains as the most common type of radiation therapy. The main drawback is that radiation deposits dose in healthy tissue before reaching its target. Boron neutron capture therapy (BNCT) is based on the nuclear capture and fission reactions that occur when (10)B is irradiated with low-energy (0.0025 eV) thermal neutrons. The resulting (10)B(n,α)(7)Li capture reaction produces high linear energy transfer (LET) α particles, helium nuclei ((4)He), and recoiling lithium-7 ((7)Li) atoms. The short range (5-9 μm) of the α particles limits the destructive effects within the boron-containing cells. In theory, BNCT can selectively destroy malignant cells while sparing adjacent normal tissue at the cellular levels by delivering a single fraction of radiation with high LET particles. HISTORY: BNCT has been around for many decades. Early studies were promising for patients with malignant brain tumors, recurrent tumors of the head and neck, and cutaneous melanomas; however, there were certain limitations to its widespread adoption and use. CURRENT LIMITATIONS AND PROSPECTS: Recently, BNCT re-emerged owing to several developments: (1) small footprint accelerator-based neutron sources; (2) high specificity third-generation boron carriers based on monoclonal antibodies, nanoparticles, among others; and (3) treatment planning software and patient positioning devices that optimize treatment delivery and consistency

Rheology of bio-edible oils according to several rheological models and its potential as hydraulic fluid

Today's concern of protecting the environment has encouraged the research and the use of environmental friendly products. Bio-edible oils are potential energy transport media in hydraulic and lubricating systems. The use of bio-edible or vegetable oils as hydraulic fluid would help to minimize hazardous pollution caused by accidental spillage, lower disposal costs of the used fluid, and help the user industry to comply with environmental safety regulations. In order to successfully use these oils, an understanding of the oil properties is necessary in order to overcome the possible failures or obstacles that might occur in real operating conditions. Rheological property is one of the most important parameters and for this reason this parameter was investigated. The present work evaluates the temperature and shear rate effects of food grade oils that include palm, coconut, canola, corn and sunflower oils. A couette-type viscometer was used to determine the flow behavior of the oils at different temperatures and discrete shear rates that are ranged 40–100 °C and 3–100 rpm, respectively. Various empirical models such as Ostwald de-Waele, Cross, Carreau, Herschel–Bulkley and Arrhenius-type relationship were used to evaluate the experimental data. The influence of shear rate and temperature on the variation of viscosity was clearly observed but temperature has more significant influence. Interpretations of rheological models indicate that these food grade oils belong to pseudo-plastic category. The palm and sunflower oils are highly stable in terms of shear rate and temperature, respectively. The overall results suggest the potential substitution of food grade oils as an energy transport media