Affibody molecules: Engineered proteins for therapeutic, diagnostic and biotechnological applications

Abstract

a b s t r a c tAffibody molecules are a class of engineered affinity proteins with proven potential for therapeutic, diagnostic and biotechnological applications. Affibody molecules are small (6.5 kDa) single domain proteins that can be isolated for high affinity and specificity to any given protein target. Fifteen years after its discovery, the Affibody technology is gaining use in many groups as a tool for creating molecular specificity wherever a small, engineering compatible tool is warranted. Here we summarize recent results using this technology, propose an Affibody nomenclature and give an overview of different HER2-specific Affibody molecules. Cumulative evidence suggests that the three helical scaffold domain used as basis for these molecules is highly suited to create a molecular affinity handle for vastly different applications.

A truncated and dimeric format of an Affibody library on bacteria enables FACS‐mediated isolation of amyloid‐beta aggregation inhibitors with subnanomolar affinity

“…J. 2015, 10, 1707-1718 therapies [8,16,17]. Alternative scaffold-proteins are in general much smaller than full-length antibodies and can usually be engineered into multivalent as well as multispecific units with an overall size that remain smaller than the conventional antibody [17,18].…”

“…Such features can potentially improve in vivo biodistribution of the agent [19][20][21][22]. One type alternative binding-protein that has been investigated for various diagnostic and therapeutic applications is the small three-helical bundle Affibody molecule (6.5 kDa) [17,23]. We previously generated an Affibody molecule (denoted Z Ab3 ) targeting monomeric Ab with a 17 nM affinity, as determined by isothermal titration calorimetry (ITC) and confirmed by surface plasmon resonance SPR [24][25][26].…”

“…To meet these ends, we here set out to generate improved highaffinity variants of the previously generated Ab-specific Affibody molecule. Affibody molecules have previously been successfully investigated as diagnostic and therapeutic agents in both preclinical and clinical studies for cancer [17]. …”

Imaging of HER3-expressing xenografts in mice using a 99mTc(CO)3-HEHEHE-ZHER3:08699 affibody molecule

“…By randomization of 13 surface-exposed residues, diverse molecular libraries have been generated from which high-affinity binders have been selected by various display techniques [16]. Until today, a number of affibody molecules with subnanomolar affinities to cancer-associated molecular targets such as HER2 [17], HER1 [18], and IGF-1R [19] have been developed and evaluated as imaging agents.…”

Evaluation of backbone-cyclized HER2-binding 2-helix Affibody molecule for In Vivo molecular imaging

“…Affibody molecules can be selected to bind different proteins with high affinity by randomization of thirteen amino acids on helices 1 and 2 [2]. Their small size facilitates high rates of extravasation and tissue penetration, and rapid blood clearance of unbound tracer molecules [3].…”