Patent ID: 8247180

Claim:
A method of detecting a homodimer comprising a dimer of a membrane-associated analyte on a cell membrane, the method comprising the steps of: (a) providing a first binding compound specific for a first antigenic determinant of the membrane-associated analyte, wherein the first binding compound has a first molecular tag attached thereto by a cleavable linkage, and wherein the first molecular tag has a first separation characteristic; (b) providing a second binding compound specific for a second antigenic determinant of the membrane-associated analyte, wherein the second binding compound has a second molecular tag attached thereto by a cleavable linkage, and wherein the second molecular tag has a second separation characteristic that is different than the first separation characteristic of the first molecular tag of the first binding compound; (c) providing a cleaving probe specific for the first antigenic determinant of the membrane-associated analyte, wherein: (i) the cleaving probe has a cleavage-inducing moiety with an effective proximity to the cleavable linkage of the first binding compound when the cleaving probe and the first binding compound are each bound to one first antigenic determinant of membrane-associated analyte in the homodimer, (ii) the cleavage probe has a cleavage-inducing moiety with an effective proximity to the cleavable linkage of the second binding compound when the cleaving probe is bound to the first antigenic determinant of the membrane-associated analyte and the second binding compound is bound to the second antigenic determinant of either the same membrane-associated analyte or the other membrane-associated analyte in the homodimer, and (iii) only one of either the cleaving probe or the first binding composition can specifically bind to the first antigenic determinant of one membrane-associated analyte; (d) mixing the cleaving probe, the first binding compound, the second binding compound, and the cell membrane such that (i) if a homodimer is present, the cleaving probe and the first binding compound each specifically bind to one first antigenic determinant of the membrane-associated analyte in the homodimer and the first molecular tag is released; (ii) if a homodimer is present, the cleaving probe binds to the first antigenic determinant of one of the membrane associated analytes in the homodimer and the second binding compound binds to the second antigenic determinant of each membrane associated analytes in the homodimer, and the second molecular tag is released from the second binding compounds; and (iii) if a monomer is present, the cleaving probe binds to the first antigenic determinant of the membrane associated analyte and the second binding compound binds to the second antigenic determinant of the membrane associated analyte, and the second molecular tag is released; and (e) separating and detecting the released molecular tags to determine the presence or the amount of homodimer in the cell membrane.