Patent ID: 7931903

Claim:
A method of delivering a therapeutic or diagnostic agent to a target cell that expresses CD74 comprising: a) exposing the target cell to a humanized anti-CD74 antibody or antigen binding fragment thereof, wherein said antibody or fragment thereof: (i) is internalized by Raji lymphoma cells in culture; (ii) induces apoptosis of Raji cells in cell culture when cross-linked with goat antisera reactive with the Fc of a human IgG; (iii) competes for binding to CD74 with, or binds to the same epitope of CD74 as, an anti-CD74 antibody comprising the light chain complementarity-determining region (CDR) sequences CDR1 (RSSQSLVHRNGNTYLH; SEQ ID NO:16), CDR2 (TVSNRFS; SEQ ID NO:17), and CDR3 (SQSSHVPPT; SEQ ID NO:18) and the heavy chain CDR sequences CDR1 (NYGVN; SEQ ID NO:19), CDR2 (WINPNTGEPTFDDDFKG; SEQ ID NO:20), and CDR3 (SRGKNEAWFAY; SEQ ID NO:21); wherein said humanized anti-CD74 antibody or fragment thereof is attached to at least one diagnostic or therapeutic agent.