Immunohistochemical Characterization of a New Monoclonal Antibody (3F5) Against MCF7 Breast Cancer Cells

In an attempt to identify estrogen regulated antigens in breast cancer cells, we have generated murine monoclonal antibodies (MoAbs) using the estrogen-dependent human breast cancer cell line MCF7 as the immunogen. BALB/C mice were stimulated with injection of vital MCF7 cells grown in Dùllbecco’s Modified Eagle Medium supplemented with 10% fetal calf serum (FCS), 100 lU/ml penicillin, 100 µg/ml streptomycin and 10- 7 M β-estradiol. Spleen cells were fused with NS1 mouse myeloma cells. Of 235 hybrid colonies supernatant of 65 reacted by ELISA with estrogen stimulated MCF7 cells. The positive supernatants were subsequently screened on MCF7 cells grown in D-MEM supplemented with FCS stripped from endogenous hormones by incubation with dextran coated charcoal pellet. In this way we obtained 4 different MoAbs that showed a minimal reactivity toward MCF7 cells grown in stripped medium.