Purification and Identification of Cell Surface Antigens using Lamprey Monoclonal Antibodies

The evolutionary distance of lampreys from humans in conjunction with their distinct antibody architecture is profound. Thus, lampreys may provide antibodies with specificity for antigens unrecognized by conventional mammalian antibodies. This study investigates lamprey based monoclonal variable lymphocyte receptor antibodies (VLRs) for purifying and identifying an antigen by tandem mass spectrometry. VLRs specific for clinically relevant cell populations were isolated. Subsequently, utilizing intrinsic VLR affinity, with or without covalent cross-linking molecules, for immunoprecipitating VLR protein antigens was tested. In one case, CD5 glycoprotein from Jurkat T cells was purified by a VLR; the antigen was identified by tandem mass spectrometry. Antibody specificity was validated by western blotting and flow cytometry. Furthermore, VLR binding to CD5 required multimerization of the antibody, indicating the individual VLR units likely bind antigen with low affinity. The study provides ‘proof of concept’ for human biomarker identification using novel lamprey monoclonal antibodies.MAS