9 1994 by Humana Press Inc. All rights of any nature whatsoever reserved. 0273-228919414702-03--0191503.00 Selection of Functional Human Immunogiobulin Light Chains from a Phage-Display Library SONIA TYUTYULKOVA AND SUDHIR PAUL" Department of Anesthesiology, University of Nebraska Medical Center, Omaha, NE ABSTRACT Human ~-light chains (L chains) were amplified by the reverse transcriptase-polymerase chain reaction (PCR) and cloned into a phagemid vector. Phage particles displaying L chains were fraction- ated on immobilized vasoactive intestinal peptide (VIP). The resultant phage preparation displayed saturable binding of (tyrl~ One of the L-chain clones (hk13) was deduced to be related to subgroup I of ~-light chains based on its nucleotide sequence. The VIP binding activity of the soluble and phage-displayed form of this L chain was confirmed by radioimmunoassay and ELISA, respectively. These observations demonstrate the potential of selecting antigen-specific L chains from phage-display libraries. Index Entries: VIP; light chains; phage-display libraries. INTRODUCTION Autoantibodies to vasoactive intestinal peptide (VIP) found in patients with asthma are capable of efficient cleavage of this peptide (1,2). The L chains purified from the IgG of a human subject positive for VIP binding and hydrolyzing autoantibodies have been observed to hydrolyze VIP with specific activity 32-fold greater than that of Fab (3). The L chain of a monoclonal antibody binds VIP with affinity only fivefold lower than that of the parent antibody (4). These findings raise the possibility that the heavy (H chains) and L chains may provide distinct contributions in the binding and hydrolysis of VIP by antibodies. Moreover, free L chains are *Author to whom all correspondence and reprint requests should be addressed. Applied Biochemistry and Biotechnology 1 9 1 Vol. 4 7, 1994