Article ID Journal Published Year Pages File Type
1175440 Analytical Biochemistry 2009 10 Pages PDF
Abstract

Antibody engineering technology has the potential to provide artificial antibodies with higher performance than conventional antibodies. Filamentous phage particles are often used to express a vast diversity of mutated antibody fragments from which clones displaying improved fragments can be isolated. We recently showed that hapten–biotin conjugates, combined via a linker involving a reductively cleavable disulfide bond, are useful for isolating phage clones displaying high-affinity anti-hapten antibody fragments. Here we prepare cleavable hapten–biotin conjugates and use them to isolate anti-hapten antibody fragments with relatively low affinities. Three diagnostically important steroids (estradiol-17β [E2], cortisol, and 17α-hydroxyprogesterone) were each coupled with a biotin derivative containing a disulfide bond. These conjugates could be bound simultaneously by their relevant anti-steroid antibody and NeutrAvidin, and their linkers were easily cleaved by dithiothreitol (DTT) treatment. The E2–biotin conjugate was used to generate anti-E2 single-domain antibody fragments (sdAbs). Random point mutations were introduced by error-prone PCR into the gene fragment encoding the VH domain of a mouse anti-E2 antibody, and these products were expressed as phagemid particles that were reacted with the E2–biotin conjugates that had already been immobilized on a solid-phase via NeutrAvidin. Thorough washing off of nonspecific phages and subsequent DTT treatment provided a phagemid clone that displayed a mutated sdAb with improved binding properties.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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