Association between allo-immunoreactive and xeno-immunoreactive subunits of a glycoprotein tumor-associated antigen.
Using allogeneic antibody, we previously described a tumor-associated antigen (TAA) in the urine of 68% of melanoma patients. The TAA was purified from urine of a melanoma patient and used as immunogen to develop a murine monoclonal antibody (AD1-40F4) and xenopolyclonal antibodies in a baboon. Sera from melanoma patients treated with whole melanoma cell vaccine were used as the source of human antibody to the glycoprotein antigen. Treatment with 2-mercaptoethanol and separation by sodium dodecyl sulfate/polyacrylamide gel electrophoresis resolved the high-molecular-mass glycoprotein TAA into smaller subunits. Immunoblot analysis indicates that the murine monoclonal antibody (AD1-40F4) recognized a 90-100-kDa subunit of the antigen while human anti-TAA antibodies primarily recognized a 65-kDa subunit in addition to the 90-100-kDa subunit. Baboon polyclonal antibodies recognized the same subunits plus a 120-kDa subunit. Blocking studies indicated that the murine monoclonal and baboon polyclonal antibodies recognized the closely related epitopes on the 90-100-kDa subunit, while human antibodies recognized an epitope entirely distinct from that recognized by the mouse antibody. These results demonstrate the epitope complexity associated with the high-molecular-mass glycoprotein TAA.
Euhus
D M
DM
Division of Surgical Oncology, Armand Hammer Laboratories, John Wayne Cancer Clinic, UCLA School of Medicine 90024.
Gupta
R K
RK
Morton
D L
DL
D000818:Animals; D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm / Q000276:immunology*; D001667:Binding, Competitive; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes; D006801:Humans; D007519:Isoantigens / Q000276:immunology; D008545:Melanoma / Q000276:immunology*; D051379:Mice; D008970:Molecular Weight; D010215:Papio; D013045:Species Specificity
D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm; D000939:Epitopes; D007519:Isoantigens