Single Chain Fv Fragments

Single Chain Fv Fragments (scFvs) are recombinant antibody fragments consisting of a full variable (epitope-binding) region of an immunoglobulin heavy chain covalently linked to the variable region of an immunoglobulin light chain.

ScFvs are a minimal version of an IgG molecule, which still retains the full activity, specificity and stability of a full IgG molecule. The reduced size of the scFvs allows for a more densely packed coating of the fragment’s binding regions (CDRs) providing higher assay sensitivities in ELISA, bead or biochip assays. The lack of the entire Fc region reduces the likelihood of interference from secondary antibodies or the problem of human anti-mouse antibody (HAMA) interference, as observed in assays using serum samples.

As scFvs are engineered sequences, they can be easily modified for specialised applications. Pioneering technology is used to incorporate proprietary functional expression tags, which aid in directed immobilisation and conjugation of scFvs as capture and detection ligands in biochip-based assays. ScFvs can be expressed in higher valency formats as dimeric, trimeric and even tetrameric fragments resulting in increased functional avidity.