Sprinkling in extra validation for high-value PTMs and therapeutic Abs with MILKSHAKE Western blots and Sundae ELISAs

Thoroughly validated antibodies (Abs) are crucial for the generation of meaningful scientific data. Abs for post translationally modified (PTM) protein targets in particular pose added validation challenges. The MILKSHAKE method employs surrogate proteins which are either modified or non-modified at a specific site. Western blot is used to observe the binding of PTM Abs to the surrogate proteins, indicating the specificity of the PTM Ab under test. In this study, we expand the utility of MILKSHAKE by validating acetyl and methyl specific Abs and by introducing another surrogate protein antigen based on cellulose binding domain (CBD) to evaluate Abs in a single western blot lane. This study also explores the use of 'Sundae' surrogate protein ELISA specifically for therapeutic Ab evaluation.