|Title:|| Technetium-99m labeled polypeptides for imaging|
|Abstract:||The invention relates to radiolabeled imaging of a mammalian body. The invention in particular provides for reagents labeled with technetium-99m for such imaging. The invention provides peptides which bind technetium-99m and which can be targeted to specific sites within a mammalian body.|
|Inventor(s):|| Dean; Richard T. (Bedford, NH) |
|Assignee:|| Diatide, Inc. (Londonderry, NH) |
|Filing Date:||Jun 07, 1995|
|Claims:||1. A polypeptide reagent for preparing a scintigraphic imaging agent, the reagent comprising, in combination: |
(a) a specific binding peptide that specifically binds to a target site to be imaged; and
(b) a technetium binding moiety of the formula
wherein Cp is a protected cysteine amino acid residue and (aa) is any amino acid, the technetium binding moiety being covalently bound to the specific binding peptide, and wherein the reagent has an amino acid sequence of 6 to 100 amino acids.
2. A polypeptide reagent according to claim 1 wherein the specific binding peptide and the technetium binding moiety are covalently linked through from one to about ninety amino acids.
3. A polypeptide reagent according to claim 1 wherein the sidechain sulfur atom of the cysteine residue is protected by a protecting group of the formula
wherein R is lower alkyl having 1 to 6 carbon atoms, phenyl, or phenyl substituted with lower alkyl, hydroxy, lower alkoxy, carboxy, or lower alkoxycarbonyl, or 2-pyridyl, 3-pyridyl, or 4-pyridyl.
4. A polypeptide reagent according to claim 1 wherein the Cp(aa) Cp moiety has the formula:
5. A polypeptide reagent according to claim 1 wherein the specific binding peptide specifically binds to clots, tumors, sites of infection, atherosclerotic plaques, amyloid plaques or bone.
6. A polypeptide reagent according to claim 1 wherein the specific binding peptide is selected from the group consisting of: