Preparation and use of immunoconjugates

A method for diagnosing the presence of a disease in a mammal, said method comprising the steps of:

• (a) administering to a mammal an effective imaging amount of a composition comprising an immunoconjugate and a pharmaceutically acceptable carrier, wherein said immunoconjugate comprises a detectable label and an antibody fragment having a carbohydrate moiety attached at about amino acid position 18 of the light chain of said antibody fragment, wherein said detectable label is conjugated to said carbohydrate moiety of said antibody fragment, and wherein said antibody fragment specifically binds to an antigen which is associated with said disease;
• and
• (b) using in vivo imaging to detect the presence of said immunoconjugate at disease sites.

A mutated recombinant antibody or antibody fragment having a non-natural Asn-glycosylation site at about position 18 of the light chain of said antibody or antibody fragment.

A method for preparing a glycosylated mutated recombinant antibody or antibody fragment, comprising the steps of:

• (a) culturing transformed host cells which express and glycosylate a mutated antibody or antibody fragment comprising a mutated light chain and a heavy chain, said host cells being transformed with an expression vector into which is cloned a mutated DNA molecule encoding a mutated light chain containing a non-natural Asn-glycosylation site at about amino acid position 18;
• and
• (b) recovering expressed and glycosylated mutated antibody or antibody fragment from said cultured host cells.

A method for treating a disease in a mammal, said method comprising administering to said mammal an effective therapeutic amount of a composition comprising an immunoconjugate and a pharmaceutically acceptable carrier, wherein said immunoconjugate comprises an antibody fragment having a carbohydrate moiety attached at about amino acid position 18 of the light chain of said antibody fragment and a non-antibody moiety selected from the group consisting of a drug, a toxin, a chelator, a boron addend and a therapeutic radioisotope, wherein said non-antibody moiety is covalently bound to said carbohydrate moiety of said antibody fragment, and wherein said antibody fragment specifically binds to an antigen which is associated with said disease.