Monoclonal antibodies to membrane components of human breast cancer cell line MDA-MB-231. Production and reactivity with various cells in culture.

Hybridoma clones were established by fusing spleen cells from mice hyperimmunized with human breast cancer cells of MDA-MB-231 line with murine myeloma cells P3-X63-Ag8-653. Ten permanent hybridomas were stabilized. The monoclonal antibodies of three of them, i.e. HBCA-6, HBCA-4 and HBCA-12 were tested against 20 various established cell lines. The most restricted binding properties showed HBCA-12 antibody which reacted positively only with two types of target cells. The cross-reactivity of HBCA-12 with human breast cancer cell line MDA-MB-231 and human myeloma derived cells ARH-77 is discussed in view of the pertinent target structure, i.e. differentiation antigens, allospecific antigens, hormone receptors and shared tumor associated antigens. It was shown that the target structure for HBCA-12 is localized on the cell surface.