Lysophosphatidic acid (LPA)-antibody (504B3)validation by free-solution assay and interferometry identifies off-target binding

Abstract

Antibody specificity and sensitivity is required in basic and clinical research for ensuring scientific rigor and reproducibility, while off-target cross-reactivity could generate erroneous conclusions. Lysophosphatidic acid (LPA) is a bioactive lipid being targeted clinically by antibody strategies. Here, we reexamined binding properties of a commercially available monoclonal antibody (504B3) reported as specific for LPA using a free-solution assay measured in a compensated interferometric reader. The antibody showed comparable binding affinities to LPA and non-LPA lipids including phosphatidic acid (PA) and lysophosphatidylcholine (LPC). These results may alter conclusions drawn from current and past basic and clinical studies employing anti-LPA antibodies.