Production of a Monoclonal Antibody as Immunohistochemical Marker on Paraffin Embedded Tissues Using a New Immunization Method

This report describes a method for the production of murine monoclonal antibodies (MAbs) against cellular antigens preserved during formol fixation and paraffin embedding of human tissues in an attempt to select markers that would be useful in immunopathology. Hybridomas were prepared using spleen cells from mice immunized with cell suspensions obtained from formalin-fixed paraffin block sections of a human breast carcinoma. A monoclonal antibody 83 D₄ was selected, which was reactive with paraffin embedded breast carcinoma tissues, but not with normal breast. The reactive antigen has a high molecular weight ( 400-1000 kD) and was detected on the cell surface of live human breast cancer cell lines and on frozen tissues sections. These results demonstrate that the MAb 83 D₄ identifies a native breast tumor associated epitope conserved during tissue fixation and embedding and could be used as an immunohistochemical marker.