Abstract: This invention provides a method for the in vivo delivery of oligonucleotides. The invention utilizes the presence of one or plurality of HES linked to an oligonucleotide to deliver a nucleic acid sequence of interest into the cytoplasm of cells and tissues of live organisms. The delivery vehicle is nontoxic to cells and organisms. Since delivery is sequence-independent and crosses membranes in a receptor-independent manner, the delivered oligonucleotide can target complementary sequences in the cytoplasm as well as in the nucleus of live cells. Sequences of bacterial or viral origin can also be targeted. The method can be used for delivery of genes coding for expression of specific proteins, antisense oligonucleotides, siRNAs, shRNAs, Dicer substrates, miRNAs, anti-miRNAs or any nucleic acid sequence in a living organism. The latter include mammals, plants, and microorganisms such as bacteria, protozoa, and viruses.

Abstract: The present invention provides for novel reagents whose fluorescence increases in the presence of particular proteases. The reagents comprise a characteristically folded peptide backbone conjugated to two fluorophores such that the fluorophores are located opposite sides of a cleavage site. When the folded peptide is cleaved, as by digestion with a protease, the fluorophores provide a high intensity fluorescent signal at a visible wavelength. Because of their high specificity and their high fluorescence signal in the visible wavelengths, these protease indicators are particularly well suited for detection of protease activity in biological samples, in particular in frozen tissue sections. Thus this invention also provides for methods of detecting protease activity in situ in frozen sections.

Abstract: This invention provides a non-radioactive assay to monitor and quantify the target-cell killing activities mediated by cytotoxic T lymphocytes (CTLs). This assay is predicated on the discovery that apoptosis pathway activation and, in particular, caspase activity, provides a measure of cytotoxic effector cell activity. In one embodiment, measurement of CTL-induced caspase activation in target cells is achieved through detection of the specific cleavage of fluorogenic caspase substrates. This assay reliably detects antigen-specific CTL killing of target cells, and provides a more sensitive, more informative and safer alternative to the standard 51Cr-release assay most often used to quantify CTL responses. The assay can be used to study CTL-mediated killing of primary host target cells of different cell lineages, and enables the study of antigen-specific cellular immune responses in real time at the single-cell level.