Monospecific antibodies recognize and bind a single epitope, giving them greater target specificity than polyreactive antibodies. It is generally assumed that monoclonal antibodies are monospecific, however, the specific epitope recognized by a monoclonal antibody may not be unique and the antibody will bind to any other protein exposing this same epitope. Furthermore, genetic diversity within individual hybridomas can give rise to additional antibody heavy and light chains that have the potential to reduce the signal-to-noise ratio when performing common immunoassay techniques. To determine whether an antibody is monospecific, Antibodies.com has incorporated the use of protein microarrays into the product validation process. The HuProt™ Human Protein Microarray, created at the Johns Hopkins University School of Medicine, is widely used for these types of validation studies, where it allows for antibody screening against >21,000 different full-length human proteins. These represent >81% of canonically expressed proteins as defined by the Human Protein Atlas, and include major functional classes such as membrane proteins, transcription factors, and cytokines, as well as proteins with tissue-specific enrichment. To produce the HuProt™ Human Protein Microarray, sequence-confirmed plasmids are used to synthesize GST-tagged versions of each protein in yeast. The proteins are then purified and printed onto glass slides in duplicate along with various controls, including GST, BSA, and histones. By incubating the antibody of interest with the array, before using a labeled secondary antibody for detection, it is possible to identify off-target binding events. During analysis of the protein array data, the antibody is given a Z-score and an S-score. The Z-score corresponds to the strength of the signal that is produced by the antibody binding to a particular protein and is reported as the number of standard deviations above the mean value of all signals generated on the array. The S-score is calculated by ranking the targets in descending order of the Z-score and measuring the difference between the Z-scores of individual proteins. For example, if an antibody binds to protein X with a Z-score of 43 and to protein Y with a Z-score of 14, then the S-score for binding to protein X is equal to 29. An S-score of at least 2.5 is required for an antibody to be considered specific for its intended target. Explore our range of monospecific antibodies below and discover more, for less.