T cell sensitivity to antigen is intrinsically regulated during maturation to ensure proper development of immunity and tolerance, but how this is accomplished remains elusive. Here we show that increasing miR-181a expression in mature T cells augments the sensitivity to peptide antigens, while inhibiting miR-181a expression in the immature T cells reduces sensitivity and impairs both positive and negative selection. Moreover, quantitative regulation of T cell sensitivity by miR-181a enables mature T cells to recognize antagonists-the inhibitory peptide antigens-as agonists. These effects are in part achieved by the downregulation of multiple phosphatases, which leads to elevated steady-state levels of phosphorylated intermediates and a reduction of the T cell receptor signaling threshold. Importantly, higher miR-181a expression correlates with greater T cell sensitivity in immature T cells, suggesting that miR-181a acts as an intrinsic antigen sensitivity "rheostat" during T cell development.

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The antimicrobial activity of LISTEX P100, Salmonella CG4, and E. coli AG10 bacteriophages were preserved in pullulan-trehalose mixture as dried films and as coatings on food packaging. The phages encapsulated in pullulan-trehalose films were able to retain infectivity for up to 3 months at ambient storage conditions. Various buffers, disaccharides and disaccharide concentrations were investigated to optimize the long-term stability of the phages in the films. It was found that pullulan and trehalose need to be simultaneously present in the film to provide the stabilizing effect and that the presence of buffers that lead to the formation of crystals in the films must be avoided for phage activity to be maintained. Overall, this study describes a method of preserving bacteriophage activity in a dried format that has great potential for use as coatings, which can be used to create antimicrobial surfaces for food preparation and for food preservation.