The bispecific antibodies of the present invention are in the form of a heteroconjugate that inhibits growth and induces apoptosis of a diseased cell and that does not require the recruitment of effector cells. The heteroconjugate has at least two binding arms wherein each of the binding arms possesses a different specificity and need not have apoptotic activity when not conjugated to each other. Also provided are methods of treating and diagnosing a diseased cell using the bispecfic antibodies of the present invention.
