This invention relates to antibodies that specifically bind HER2/neu, and particularly chimeric 4D5 antibodies to HER2/neu, which have reduced glycosylation as compared to known 4D5 antibodies. The invention also relates to methods of using the 4D5 antibodies and compositions comprising them in the diagnosis, prognosis and therapy of diseases such as cancer, autoimmune diseases, inflammatory disorders, and infectious disease.