Abstract: Recombinant nucleic acids encoding reporting constructs for characterizing botulinum neurotoxin protease activity and cells that incorporate such recombinant nucleic acids and that are suitable for use in cell-based assays for the neurotoxin are provided. The encoded reporting constructs are a pair of recombinant hybrid proteins that act in concert, and can include an N-terminal palmitoylation sequence. The reporting constructs are a pair of recombinant hybrid proteins that act in concert, and that include a botulinum neurotoxin protease recognition and cleavage sequence positioned to release a fluorophore upon cleavage.

Abstract: Compositions and methods for improved cell-based methods of characterizing botulinum neurotoxins are provided. Cells utilized in these methods include a reporting construct that is cleaved following uptake and processing of botulinum neurotoxin by the cell, resulting in proteolysis of the portion of the reporting construct that is released following cleavage. The released portion includes a fluorophore and amino acid substitutions or sequences that enhance the rate of proteolysis. A pair of reporting constructs can be utilized in which one member of the pair is modified to resist cleavage by the botulinum neurotoxin while co-localizing with the remaining member of the pair.

Abstract: Cells are described that are useful in rapid, sensitive, and accurate cell-based assays for enzyme activity, particularly for enzyme activities associated with botulinum toxins. Such cell expresses a construct that includes an anchor region, a cleavage site, and a reporting region having two or more identical reporter peptides. Enzymatic activity at the cleavage site releases the reporter region into the cytosol of the cell, where multiple degradation events occur. The observed change in the signal is proportional to the enzymatic activity.

Abstract: Recombinant nucleic acids encoding reporting constructs for characterizing botulinum neurotoxin protease activity and cells that incorporate such recombinant nucleic acids and that are suitable for use in cell-based assays for the neurotoxin are provided. The encoded reporting constructs are a pair of recombinant hybrid proteins that act in concert, and can include an N-terminal palmitoylation sequence. The reporting constructs are a pair of recombinant hybrid proteins that act in concert, and that include a botulinum neurotoxin protease recognition and cleavage sequence positioned to release a fluorophore upon cleavage.

Abstract: Systems are described in which a primary detergent or surfactant in an aqueous solution is removed by the addition of a secondary detergent or surfactant in concentrations that exceed the critical micellar concentration (CMC) of the secondary detergent or surfactant using a size separation device. These systems are particularly applicable to protein-containing solutions. Typical primary detergents/surfactants include polysorbate 20, polysorbate 80, and Triton X-100. Suitable secondary detergents or surfactants can be ionic, nonionic, or zwitterionic. Typical secondary detergents/surfactants include, but are not limited to, galactoside detergents (e.g. octyl-?-galactoside), glucamide detergents (e.g. MEGA 8, MEGA 9, MEGA 10), cholamide detergents (e.g. CHAPS, CHAPSO, BIGCHAPS), and sulfobetaine detergents (such as sulfobetaine 3-10).

Abstract: Recombinant nucleic acids encoding reporting constructs for characterizing botulinum neurotoxin protease activity and cells that incorporate such recombinant nucleic acids and that are suitable for use in cell-based assays for the neurotoxin are provided. The encoded reporting constructs are a pair of recombinant hybrid proteins that act in concert. The reporting constructs are a pair of recombinant hybrid proteins that act in concert, and that include a botulinum neurotoxin protease recognition and cleavage sequence positioned to release a fluorophore upon cleavage.

Abstract: Compositions and methods for improved cell-based methods of characterizing botulinum neurotoxins are provided. Cells utilized in these methods include a reporting construct that is cleaved following uptake and processing of botulinum neurotoxin by the cell, resulting in proteolysis of the portion of the reporting construct that is released following cleavage. The released portion includes a fluorophore and amino acid substitutions or sequences that enhance the rate of proteolysis. A pair of reporting constructs can be utilized in which one member of the pair is modified to resist cleavage by the botulinum neurotoxin while co-localizing with the remaining member of the pair.

Abstract: Cells are described that are useful in rapid, sensitive, and accurate cell-based assays for enzyme activity, particularly for enzyme activities associated with botulinum toxins. Such cell expresses a construct that includes an anchor region, a cleavage site, and a reporting region having two or more identical reporter peptides. Enzymatic activity at the cleavage site releases the reporter region into the cytosol of the cell, where multiple degradation events occur. The observed change in the signal is proportional to the enzymatic activity.

Abstract: Recombinant nucleic acids encoding reporting constructs for characterizing botulinum neurotoxin protease activity and cells that incorporate such recombinant nucleic acids and that are suitable for use in cell-based assays for the neurotoxin are provided. The encoded reporting constructs are a pair of recombinant hybrid proteins that act in concert. The reporting constructs are a pair of recombinant hybrid proteins that act in concert, and that include a botulinum neurotoxin protease recognition and cleavage sequence positioned to release a fluorophore upon cleavage.

Abstract: Compositions and methods are disclosed that provide a rapid, sensitive, and accurate cell-based assay for enzyme activity, particularly for enzyme activities associated with botulinum toxins. A cell is provided that expresses a construct that includes an anchor region, a cleavage site, and a reporting region having two or more identical reporter peptides. Enzymatic activity at the cleavage site releases the reporter region into the cytosol, where multiple degradation events occur. The observed change in the signal is proportional to the enzymatic activity.

Abstract: Vesicles that incorporate reporting constructs for characterizing Botulinum neurotoxin protease activity and suitable for use in an assay are provided. The reporting constructs are a pair of recombinant hybrid proteins that act in concert. The reporting constructs are a pair of recombinant hybrid proteins that act in concert, and that include a Botulinum neurotoxin protease recognition and cleavage sequence positioned to release a fluorophore upon cleavage.

Abstract: Systems are described in which a primary detergent or surfactant in an aqueous solution is removed by the addition of a secondary detergent or surfactant in concentrations that exceed the critical micellar concentration (CMC) of the secondary detergent or surfactant using a size separation device. These systems are particularly applicable to protein-containing solutions. Typical primary detergents/surfactants include polysorbate 20, polysorbate 80, and Triton X-100. Suitable secondary detergents or surfactants can be ionic, nonionic, or zwitterionic. Typical secondary detergents/surfactants include, but are not limited to, galactoside detergents (e.g. octyl-?-galactoside), glucamide detergents (e.g. MEGA 8, MEGA 9, MEGA 10), cholamide detergents (e.g. CHAPS, CHAPSO, BIGCHAPS), and sulfobetaine detergents (such as sulfobetaine 3-10).

Abstract: Compositions and methods are described in which a primary detergent or surfactant in an aqueous solution is removed by the addition of a secondary detergent or surfactant in concentrations that exceed the critical micellar concentration (CMC) of the secondary detergent or surfactant. These compositions and methods are particularly applicable to protein-containing solutions. Typical primary detergents/surfactants include polysorbate 20, polysorbate 80, and Triton X-100. Suitable secondary detergents or surfactants can be ionic, nonionic, or zwitterionic. Typical secondary detergents/surfactants include, but are not limited to, galactoside detergents (e.g. octyl-?-galactoside), glucamide detergents (e.g. MEGA 8, MEGA 9, MEGA 10), cholamide detergents (e.g. CHAPS, CHAPSO, BIGCHAPS), and sulfobetaine detergents (such as sulfobetaine 3-10).

Abstract: Compositions for determining the efficacy and/or potency of a vaccine preparation are described herein. Splenocytes from immunized animals are isolated and can be frozen. Upon thawing such cells are activated by exposure to a series of dilutions of a vaccine preparation being tested and a series of dilutions of a reference vaccine with known characteristics. Cells secreting immunogen-specific antibody and cells secreting nonspecific antibody are enumerated, as is the amount of immunogen-specific and nonspecific antibody produced. Comparison between the results from the vaccine preparations provides a measure of relative vaccine efficacy and/or potency.

Abstract: Compositions and methods for determining the efficacy and/or potency of a vaccine preparation are described herein. Splenocytes from immunized animals are isolated and frozen. Upon thawing aliquots these cells are activated by exposure to a series of dilutions of q vaccine preparation being tested and a series of dilutions of a reference vaccine with known characteristics. Cells secreting immunogen-specific antibody and cells secreting nonspecific antibody are enumerated, as is the amount of immunogen-specific and nonspecific antibody produced. Comparison between the results from the vaccine preparations provides a measure of relative vaccine efficacy and/or potency.

Abstract: Compositions and methods for characterization binding proteins are described that include use of a reporting construct that incorporates a bait region that interacts with the binding protein and a reporter that is susceptible to degradation in the reporter's local environment. Complex formation between the bait region and the binding protein provides protection of the susceptible reporter from degradation. Such a reporting construct can be utilized to identify cells expressing a binding protein when the susceptible reporter is susceptible to degradation in cytosol.

Abstract: Cell based assays for botulinum neurotoxin are provided. Specific neurotoxin uptake or proteolytic activity directed to reporting constructs sensitive to botulinum neurotoxin in cells capable of being intoxicated by botulinum neurotoxin is enhanced by increasing expression of SV2 or heat shock proteins in such cells, respectively.

Abstract: Compositions and methods for improved cell-based methods of characterizing botulinum neurotoxins are provided. Cells utilized in these methods include a reporting construct that is cleaved following uptake and processing of botulinum neurotoxin by the cell, resulting in proteolysis of the portion of the reporting construct that is released following cleavage. The released portion includes a fluorophore and amino acid substitutions or sequences that enhance the rate of proteolysis. A pair of reporting constructs can be utilized in which one member of the pair is modified to resist cleavage by the botulinum neurotoxin while co-localizing with the remaining member of the pair.

Abstract: Methods for increasing specific uptake of a Botulinum neurotoxin are provided. Specific neurotoxin uptake by cells capable of being intoxicated by Botulinum neurotoxin is enhanced by increasing temperature from about 37° C. to up to about 41° C., as indicated by a decrease in the EC50 found for cells so treated. The effect requires the presence of both heavy and light chains of the Botulinum neurotoxin, and is serotype selective.

Abstract: Compositions for characterization of botulinum toxin (BoNT) are described that include a genetically modified cell that is transfected with an artificial construct comprising a nucleic acid sequence that encodes for a hybrid protein having (a) a reporter-containing portion chemically coupled to (b) a cleavage site and (c) a control fluorophore. The cleavage site interacts with a BoNT in a manner that cleaves the reporter-containing portion from remainder of the construct. The cleaved portion is destroyed or otherwise degraded by the local environment, and presence of BoNT is evidenced by reduction in signal from the reporter. The cleavage sequence is all or part of a SNARE protein, the cleavable reporter-containing portion is preferably Yellow Fluorescent Protein (YFP), Citrine, Venus, or a YPet protein and the control fluorophore is preferably CFP, mStrawberry, or a mCherry protein.