Analyzers and analyzer systems that include an analyzer for determining multiple label species, methods of using the analyzer and analyzer systems to analyze samples, are disclosed herein. The analyzer includes one or more sources of electromagnetic radiation to provide electromagnetic radiation at wavelengths within the excitation bands of one or more fluorophore species to an interrogation space that is translated through the sample to detect the presence or absence of molecules of different target analytes. The analyzer may also include one or more detectors configured to detect electromagnetic radiation emitted from the one or more fluorophore species. The analyzer for determining multiple target molecule species provided herein is useful for diagnostics because the concentration of multiple species of target molecules may be determined in a single sample and with a single system.

Fibronectin type III (.sup.10Fn3) binding domains having novel designs that are associated with reduced immunogenicity are provided. The application describes alternative .sup.10Fn3 binding domains in which certain immunogenic regions are not modified when producing a binder in order to maintain recognition as a self antigen by the host organism. The application also describes .sup.10Fn3 binding domains in which HLA anchor regions have been destroyed thereby reducing the immunogenic contribution of the adjoining region. Also provided are .sup.10Fn3 domains having novel combinations of modified regions that can bind to a desired target with high affinity.

Methods for proteomic screening on random protein-bead arrays by mass spec is described. Photocleavable mass tags are utilized to code a protein library (bait molecules) displayed on beads randomly arrayed in an array substrate. A library of probes (prey) can be mixed with the protein-bead array to query the array. Because mass spec can detect multiple mass tags, it is possible to rapidly identify all of the interactions resulting from this mixing.

The present invention is a method for determining the identity of the epitopes recognized by T-cells. The method consists of expressing an encoded library of candidate epitope sequences in a recipient reporter cell capable of providing a detectable signal upon cytotoxic attack from a single cognate T-cell followed by contacting the reporter cells with T-cells of interest. The reporter cells with a signal indicating cytotoxic attack from a T-cell are isolated and then analyzed by next-generation sequencing in order to identify the epitope sequences.

Materials and methods for specifically isolating and identifying biomolecules that bind to selected targets.

Methods are disclosed for identifying one or more proteins or polypeptides comprised by a sample. The methods comprise determining binding of each polypeptide with respect to each binding pool of a plurality of binding pools, wherein each binding pool comprises one or more probes which bind a structure comprised by a protein or polypeptide. In some aspects, polypeptides can be denatured and separated into individual polypeptide strands and immobilized on a solid support prior to determining binding of the binding pools. A protein, polypeptide or polypeptide strand can be identified by searching, in at least one database, for a protein or polypeptide sequence comprising binding pool targets either identical to or most similar to the binding pool targets comprised by the protein, polypeptide or polypeptide strand to be identified. Kits for identifying proteins, polypeptides and polypeptide strands are also disclosed.

Methods and compositions for multiplexed protein-protein interaction profiling (e.g., immunoprofiling), based on nucleic acid tagging of polypeptides (e.g., by RNA display) are described. In some embodiments the described compositions and methods utilize a library of prey polypeptide targets linked to prey RNAs encoding them, and a population of bait polypeptides, e.g., a mixture of antibodies, that bind to one or more of the prey polypeptide targets and are used to isolate and identify the bound prey polypeptide targets by amplification of their associated prey RNAs and sequencing of the corresponding cDNAs. In other embodiments the prey polypeptide targets are linked to DNA Bar Codes, which serve as unique identifiers of the tagged polypeptide.

The present invention provides assays and assay systems for use in spatially encoded biological assays. The invention provides an assay system comprising an assay capable of high levels of multiplexing where reagents are provided to a biological sample in defined spatial patterns; instrumentation capable of controlled delivery of reagents according to the spatial patterns; and a decoding scheme providing a readout that is digital in nature.

The disclosure features methods of identifying specific drug candidates for disease treatment, the methods including: for pairs of associated expressed proteins in a protein-protein interaction network for a plurality of biological samples, comparing relative concentration values of the associated proteins in each of the biological samples to identify outliers among a distribution of the relative concentration values, identifying a set of proteins involved in dysregulated protein-protein interactions in the network based on the outliers, and predicting an efficacy of one or more drug candidates from among a set of drug candidates for treating a disease based on the identified set of proteins and information about one or more of proteins, protein complexes, biological pathways, and functional modules targeted by the set of drug candidates.

Disclosed herein are methods of detecting at least one target biomolecule in at least one single cell comprising lysing the single cell or cells and performing a cell identification assay and target identification assay. Also disclosed herein are methods for preparing a sample for undergoing single cell analysis, wherein the single cell analysis comprises performing a cell identification assay and a target identification assay.