(a) Antibody multispecificity. An antibody binds to an epitope/mimotope found within a variety of proteins from different species, leading to high affinity, specific binding of this antibody to a large number of proteins in nature.

(b) PETAL construction. PETAL is a library of 62,208 mouse monoclonal antibodies (mAbs) derived from immunization of more than 30,000 mice against 15,199 diverse peptide antigens. PETAL has the potential to recognize a great number of proteins in nature.

(c) PETAL microarray construction. PETAL is printed into an antibody microarray as a high-throughput platform for antibody/target discovery (left panel). Right panel shows the design/layout of the array (red, visualized by a Cy5-conjugated anti-mouse antibody) and an array hybridization result using a protein sample (positive-binding mAb spots are shown as green).

(d) Workflow for proteome-scale antibody generation and target discovery. Two array screening applications are shown: direct screening to identify proteome-specific mAbs and subsequent antibody application screening and target identification or differential screening to discover mAbs and their cellular targets associated with a specific phenotype.