Reactivity of anti-CD15 monoclonal antibody PM-81 with breast cancer and elimination of breast cancer cells from human bone marrow by PM-81 and immunomagnetic beads.

The CD15 carbohydrate antigen, lacto-N-fucopentaose III is expressed on a variety of human cancer cells including acute myeloid leukemia, small cell carcinoma of the lung, and colorectal carcinomas. We have found that cells from breast cancer cell lines and patient-derived tissue are strongly CD15 positive, as seen by binding to the PM-81 monoclonal antibody. In this report we show that monoclonal antibody PM-81 and immunomagnetic beads can remove breast cancer cells from bone marrow and thus be used as "purging" agents for autologous bone marrow transplantation. PM-81 and immunomagnetic beads removed up to 3 log of SK-BR-3 and MCF7 breast carcinoma cell line cells while minimally affecting normal hematopoietic progenitor cells. This technique may be useful for purging marrow for autologous bone marrow transplantation in breast cancer.