Immunoglobulin half-molecules and process for producing hybrid antibodies

Claim 2

A substantially pure covalent hybrid antibody consisting essentially of two different heavy chain-light chain half-molecules, wherein the first of said half-molecules provides a binding site for a first antigen and the second of said half-molecules provides a chemically different binding site for the first or a second antigen; and wherein said half-molecules are bonded to each other through disulfide linkage.

Claim 3

The covalent hybrid antibody of claim 1 wherein the first and second half-molecules provide chemically different binding sites for different antigens.

Claim 4

The covalent hybrid antibody of claim 2 wherein the first half-molecule provides a binding site for an analyte and the second half-molecule provides a binding site for an indicator.

Claim 5

The covalent hybrid antibody of claim 3 wherein the analyte is selected from the group consisting of protein, hormone, drug, vitamin, enzyme, antibody, polysaccharide, bacterium, protozoa, fungi, virus, cell and tissue antigens.

Claim 6

The covalent hybrid antibody of claim 3 wherein the indicator is selected from the group consisting of enzyme and aggregating substance.

Claim 7

A process for preparing covalent hybrid antibodies comprising the steps of: (A) selectively cleaving a first immunoglobulin molecule which is an antibody to a first antigen into its heavy chain-light chain half-molecules by sulfitolysis of the inter-heavy chain disulfide linkage to produce S-sulfonated half-molecules; (B) selectively cleaving a second immunoglobulin molecule which is an antibody to the first or a second antigen into its heavy chain-light chain half-molecules by reduction of the inter-heavy chain disulfide linkage to produce reduced half-molecules; and (C) combining the S-sulfonated half-molecules from step (A) with the reduced half-molecules from step (B).

Claim 8

A process for preparing covalent hybrid antibodies comprising the steps of: (A) selectively cleaving a first immunoglobulin molecule which is an antibody to a first antigen into its heavy chain-light chain half-molecules by sulfitolysis of the inter-heavy chain disulfide linkage to produce S-sulfonated half-molecules; (B) selectively cleaving a second immunoglobulin molecule which is an antibody to the first or a second antigen into its heavy chain-light chain half-molecules by reduction of the inter-heavy chain disulfide linkage to produce reduced half-molecules; and (C) combining the S-sulfonated half-molecules from step (A) with the reduced half-molecules from step (B).

Claim 9

The process of claim 6 wherein the reduced half-molecules are produced by reduction of the inter-heavy chain disulfide linkage.

Claim 10

The process of claim 6 wherein the reduced half-molecules are produced by sulfitolysis of the inter-heavy chain disulfide linkage followed by reduction.

Claim 11

The process of claim 8 wherein the sulfitolysis reaction comprises the steps of: (A) mixing an immunoglobulin molecule with sodium sulfite and 5,5'-dithiobis(2-nitrobenzoic acid); (B) incubating in a nonoxidizing atmosphere; and (C) separating the protein products.

Claim 12

The process of claim 7 wherein the reduced half-molecules are produced by reduction of immunoglobulin molecule bound to an immobilized receptor.

Claim 13

The process of claim 10 wherein the receptor is antigen bonded to a support.

Claim 14

The process of claim 10 wherein the receptor is Protein A bonded to a support.