Antibody mimetic

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]

Examples

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

See also

• Protein mimetic
• Optimer Ligand