Single chain antibodies specific for fatty acids derived from a semi-synthetic phage display library

The biological activities of many acylated molecules are lipid dependent. Lipids, however, are poorly immunogenic or non-immunogenic. We employed a phage display semi-synthetic human antibody library to isolate anti-lipid antibodies. Selection was done against methyl palmitate, a 16 carbon aliphatic chain, and a major component of bacterial glycolipids and lipoproteins in animal cells. The selected single chain variable fragment (scFv) bound specifically to a 16 carbon aliphatic chain and to a lesser extent to a 14 or 18 carbon aliphatic chain and poorly to either 12, 22 or 8 carbon aliphatic chains. Furthermore, the scFv prevented micelle formation of lipoteichoic acid from Gram-positive bacteria; inhibited lipopolysaccharide-induced tumor necrosis factor alpha release in mononuclear cells; bound to hydrophobic bacterial surfaces, especially those of Gram-positive bacteria, and bound to Lck, a mammalian palmitated lipoprotein. Our data suggest that the phage antibody library can be successfully employed to obtain human anti-aliphatic scFv human antibody fragment with potential therapeutic applications in neutralizing the deleterious effects of bacterial toxins as well as in structure--function analysis of lipoproteins in animal cells.