Table 2.

mAb that recognize specific conformations of GPCRs

Receptor	mAb-Source/composition	Epitope Recognized	Receptor State Detected	Pharmacology	Ref
CCR5	MC-4, MC-5, MC-7	N-terminal domain	Agonist conformation with multiple ligands bound	Agonist Inhibition	[19]
CCR5	MC-1	ICL-2	Agonist conformation	Multiple agonist inhibition	[19]
CCR5	MC-6	ECL- conformation determinant	Active conformation	Stabilizes active conformation	[19]
CXCR4	12G5	ECL-1,2 conformational	Cell type and donor specific conformations	Inhibition of chemotaxis	[55]
CXCR4	44717.111 (12G5 also examine in this paper)	Proteoliposome (PMPLs) containing CXCR4	Binds to SDF-1 bound or unbound R	Abolished binding of GP120	[56]
CXCR4		Llama immunization with CXCR4- expressing HEK293; followed by phage library selection		Antagonist and inverse agonist, binds to ECL2 and ECL3	[57]
CCR5	3A9	Phage Displayed CCR5 epitopes inferred by alanine mapping to extracellular loops and computer modeling	Not indicated	Not Indicated	[58]
β2AR	Camelid Nanobody Nb80	Cytoplasmic end of receptor projecting into the lattice	By modeling and Crystallography -the agonist active state	Intracellular loop binding no pharmacological activity noted	[59]
Rhodopsi n	K42–41L antibody selected by reactivity with a peptide in a phage display library	Epitope found in dark-adapted rhodopsin and metarhodopsin I not in metarhodopsin II and is a sequence in C3 loop	Inhibits for formation of metarhodpsin II while stabilizing metarhodpsin I- locks C3 loop into an extended conformation	Not studied	[60]