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Lysophosphatidic acid (LPA)-antibody (504B3) engagement detected by interferometry identifies off-target binding
Manisha Ray1, Yasuyuki Kihara1, Darryl J Bornhop2
1Translational Neuroscience Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
Background:
Lysophosphatidic acid (LPA) is a bioactive lysophospholipid that acts through its six cognate G protein-coupled receptors. As a family, lysophospholipids have already produced medicines (e.g., sphingosine 1-phosphate) as is being pursued for LPA through the use of specific antibodies that reduce ligand availability.
Methods:
The binding properties of a commercially available, reportedly specific, monoclonal LPA antibody named 504B3 that is related to the clinical candidate Lpathomab/LT3015 were reexamined using a free solution assay (FSA) measured in a compensated interferometric reader (CIR).
Results:
Measurement of 504B3 binding properties with an FSA-CIR approach revealed similar binding affinities for 504B3 against LPA as well as the non-LPA lipids, phosphatidic acid (PA) and lysophosphatidylcholine (LPC).
Conclusions:
Antibody binding specificity and sensitivity, particularly involving lipid ligands, can be assessed in solution and without labels using FSA-CIR. These findings could affect interpretations of both current and past basic and clinical studies employing 504B3 and related anti-LPA antibodies.
