Antibody mimetics are organic compounds that, like antibodies, can specifically bind antigens, but that are not structurally related to antibodies. They are usually artificial peptides or proteins with a molar mass of about 3 to 20 kDa. (Antibodies are ~150 kDa.)
Nucleic acids and small molecules are sometimes considered antibody mimetics as well, but not artificial antibodies, antibody fragments and fusion proteins composed from these.
Common advantages over antibodies are better solubility, tissue penetration, stability towards heat and enzymes, and comparatively low production costs. Antibody mimetics are being developed as therapeutic and diagnostic agents.[1]
Antibody mimetic | Scaffold | Molar mass | Example drug |
---|---|---|---|
Affibody molecules[2] | Z domain of Protein A | 6 kDa | ABY-025 |
Affilins[3] | Gamma-B crystallin | 20 kDa | |
Ubiquitin | 10 kDa | SPVF 2801 | |
Affimers[4] (Adhirons) | Cystatin | 12–14 kDa | |
Affitins[5] | Sac7d (from Sulfolobus acidocaldarius) | 7 kDa | |
Alphabodies[6] | Triple helix coiled coil | 10 kDa | CMPX-1023 |
Anticalins[7] | Lipocalins | 20 kDa | |
Avimers[8] | A domains of various membrane receptors | 9–18 kDa | |
DARPins[9] | Ankyrin repeat motif | 10–19 kDa | MP0112 |
Fynomers[10] | SH3 domain of Fyn | 7 kDa | |
Gastrobodies[11] | Kunitz-type soybean trypsin inhibitor | 20 kDa | |
Kunitz domain peptides[12] | Kunitz domains of various protease inhibitors | 6 kDa | Ecallantide (Kalbitor) |
Monobodies[13] | 10th type III domain of fibronectin | 10 kDa | Pegdinetanib (Angiocept) |
nanoCLAMPs[14] | Carbohydrate Binding Module 32-2 (from Clostridium perfringens NagH) | 16 kDa | |
Optimers[15] | Flexible nucleic acid based scaffold; G-quadruplex | 8-15 kDa | |
Repebodies[16] | leucine-rich repeats | ||
Pronectin™[17] | fourteenth fibronectin type-III scaffold of Human Fibronectin (14Fn3) | 10 kDa | |
Centyrins[18] | highly stable fibronectin type III (FN3) domain | 10 kDa | |
Obodies[19] | a high affinity binding protein domain engineered to bind to Hen Egg-white Lysozyme |