2 TUMOR-ASSOCIATED MEMBRANE-ANTIGENS DEFINED BY MONOCLONAL-ANTIBODIESIN A TRANSPLANTABLE SARCOMA INDUCED BY ROUS-SARCOMA VIRUS IN RAT

Two hybridoma clones have been produced by hybridization of murine mye loma cell line PAI and splenocytes from BALB/c mice immunized with cel ls from a transplantable sarcoma induced in rat by SR-RSV. The antibod y produced by hybridoma clone 2C2 was of subclass IgG3 and recognized a cell surface antigen of 52 kD. It only cross-reacted with cells from SR-RSV-induced sarcoma in hamster, but not with cells from the chicke n RSV-induced sarcoma, nor with a number of methylcholanthrene sarcoma s and various other tumors of viral or other etiology developed in rat s, mouse, hamsters or chickens. The antibody produced by hybridoma clo ne 5G2 was of subclass IgG2A and recognized an antigen of 28 kD which was located under the plasma membrane, particularly in the cell protru sions and microvilli. Cross-reactions were found with all sarcoma cell s tested, indicating that this antigen might represent a common sarcom a antigen of comparatively low molecular mass.