The present disclosure provides high-performance immunoreagents for use in a variety of immunologic assays and other related techniques. The immunoreagents comprise a primary antibody and a bridging antigen, wherein the bridging antigen is recognized by a detectable secondary antibody with high affinity. Also provided are compositions comprising panels of immunoreagents specific for multiple different target antigens and compositions comprising pairs of primary immunoreagents and their complementary detectable secondary antibodies. The paired primary immunoreagents and secondary antibodies are useful in a variety of immunologic assays, particularly in highly multiplexed assays, where the structure of the bridging antigen is varied in tandem with variation in the detectable secondary antibody, such that a multiplicity of immunoreagents are provided that are capable of simultaneously detecting a multiplicity of target antigens in a single assay. Also provided are kits comprising the immunoreagents, methods of immunologic assay using the immunoreagents of the disclosure, and methods of preparation of the immunoreagents.
