Methods for technetium/rhenium labeling of proteins

A method for radiolabeling a protein with substantially carrier-free Re-188 perrhenate, comprising the steps of contacting a solution of about 1-20 mg/ml of an antibody or antibody fragment containing a plurality of adjacent free sulfhydryl groups with about 100-10,000 .mu.g/ml of stannous ions under an inert gas atmosphere, storage of the reduced antibody or antibody fragment under oxygen-free conditions, and then with about 10-500 mCi of substantially carrier-free Re-188, and recovering radiolabeling protein.

A method for radiolabeling an intact antibody or a F(ab').sub.2 antibody fragment with a radioisotope of rhenium, comprising the steps of contacting a solution of an intact antibody or a F(ab').sub.2 antibody fragment containing at least one disulfide group and which specifically binds to an antigen produced by or associated with a tumor or infectious lesion, with stannous ions under an inter gas atmosphere, storage of the reduced antibody or antibody fragment under oxygen-free conditions, and then with radioperrhenate, without first subjecting said solution containing said intact antibody or a F(ab').sub.2 antibody fragment and stannous ions to a sizing column, the amount of stannous ion being in excess over that required to substantially completely reduce said radioperrhenate but not sufficient to precipitate from said solution, and recovering radiolabeled protein.

A kit for radiolabeling an antibody or antibody fragment with the Re-188 radioscope of rhenium, comprising in separate containers:

• (a) about 1-20 mg per unit dose of an antibody or antibody fragment which specifically binds an antigen associated with a tumor or an infectious lesion, and which contains a plurality of adjacent free sulfhydryl groups, and about 100-10,000 .mu.g per unit dose of stannous ions;
• and
• (b) about 10-500 mCi/mg of antibody or antibody fragment of substantially carrier-free Re-188-perrhenate.

A method for radiolabeling a protein with carrier-added Re-186, comprising the steps of contacting a solution of about 1-20 mg/ml of protein containing a plurality of adjacent free sulfhydryl groups with about 1-1,000 mg/ml of stannous ions under an inert gas atmosphere, storage of the reduced protein under oxygen-free conditions, and then with about 10-500 mCi of carrier-added Re-186-perrhenate, and recovering radiolabeled protein.

A kit for radiolabeling an antibody or antibody fragment with the Re-186 radioisotope of rhenium, comprising in separate containers:

• (a) about 1-20 mg per unit dose of an antibody or antibody fragment which specifically binds an antigen associated with a tumor or an infectious lesion, and which contains a plurality of adjacent free sulfhydryl groups, and about 1-1,000 mg per unit dose of stannous ions;
• and
• (b) about 10-500 mCi/mg of antibody or antibody fragment of carrier-added Re-186-perrhenate.