Melanoma-associated antigen p97 continues to be expressed after prolonged exposure of cells to specific antibody.

p97, a 97,000 molecular weight cell surface glycoprotein associated with human melanoma, has attracted attention as a possible target for tumor therapy. Melanoma cells were grown overnight in the presence of IgG2a or IgG1 monoclonal antibodies specific for p97, and then exposed to complement and also tested for binding of monoclonal antibodies specific for other epitopes of p97. The results indicated that melanoma cells continued to express p97 after prolonged exposure to specific antibody, a prerequisite for many therapeutic applications.