Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.04.236992v1?rss=1 Authors: Lecerf, M., Kanyavuz, A., Rossini, S., Dimitrov, J. D. Abstract: Development of monoclonal antibody therapeutics is a sophisticated process. Early stage detection of negative traits of antibodies, which can impact the production, storage stability or therapeutic efficacy is of critical importance for saving time and resources in drug development programs. Since the developability issues of antibodies are diverse, including expression yield, chemical and physical stability, propensity for aggregation, antigen-binding polyreactivity, etc., a battery of experimental and in silico assays have been developed for thorough examination of drug candidates. Here, by using a set of 113 samples with variable region sequences matching clinical-stage therapeutic antibodies, we demonstrated that unique physicochemical properties of heme allow this cofactor molecule to be applied as a probe for simultaneous detection of different deleterious characteristics of antibodies i.e., antigen-binding polyreactivity, self-association, aggregation, hydrophobicity and expression yield. Moreover, our study demonstrates that similarly as antibody repertoires from healthy individuals, a fraction of therapeutic antibodies acquires use heme as cofactor for recognition of diverse antigens. These results reveal presence of a hidden vulnerability issue for some antibodies, which would not be detectable by standard analytical assays. This liability may be of concern for monoclonal antibodies intended to be use in patients with pathophysiological conditions where extracellular heme is present e.g. hemolysis or tissue damage. We provided evidence about the mechanistic basis of the unique features of heme and offer a powerful analytical tool for rapid and simple detection of important negative traits in candidate therapeutic antibodies. Copy rights belong to original authors. Visit the link for more info