Cell surface antigens of chemically induced fibrosarcomas: detection by a monoclonal antibody of a tumor-restricted Mr 12,000 protein gag antigen encoded by a dual-tropic murine leukemia virus.
Fusion products of spleen cells of W/FuDp rats immunized with a methylcholanthrene-induced BALB/c sarcoma, CA-2, and mouse myeloma cells were screened in an attempt to identify a monoclonal antibody defining the individually distinct tumor-specific transplantation antigen of CA-2. A hybridoma, MP/69/04, was isolated which produces an IgG2a monoclonal antibody that recognized a tumor-restricted antigen of CA-2. In direct binding assay, MP/69/04 reacted only with 2 of 15 methylcholanthrene induced BALB/c sarcomas tested. Thymus, spleen, lymph nodes, bone marrow, brain, adult lung fibroblasts, newborn muscle fibroblasts and 3T3 cells were negative. Absorption tests revealed, however, expression of the MP/69/04 determinant on 8 of the 12 murine leukemia virus (MuLV) producer BALB/c sarcoma tested. The antigen was not detected on any of the three non-producer sarcomas tested nor on a wide range of normal tissues and cell lines. An N-dualtropic MuLV was isolated from CA-2, and cell lines susceptible to infection by this virus were shown to express the MP/69/04 epitope. By Western blotting, the MP/69/04 epitope was identified as being expressed on the MuLV structural protein with a molecular weight of 12,000, present in CA-2 cells and in the purified CA-2 MuLV. These results indicate the MP/69/04 antigen is not a unique tumor-specific transplantation antigen but is a gag product of a recombinant retrovirus which is expressed on the cell surface of many MuLV + methylcholanthrene-induced BALB/c fibrosarcomas.
Carbone
G
G
Pierotti
M A
MA
Boiocchi
M
M
De Leo
A B
AB
Ballinari
D
D
Radice
P
P
Borrello
M G
MG
Meseguer
A
A
Cernuschi
A
A
Parmiani
G
G
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis*; D005260:Female; D005354:Fibrosarcoma / Q000139:chemically induced / Q000276:immunology*; D015683:Gene Products, gag; D006649:Histocompatibility Antigens / Q000032:analysis; D009052:Leukemia Virus, Murine / Q000276:immunology* / Q000302:isolation & purification; D008748:Methylcholanthrene; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D014764:Viral Proteins / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D015683:Gene Products, gag; D006649:Histocompatibility Antigens; D014764:Viral Proteins; C029237:tumor-associated transplantation antigen; D008748:Methylcholanthrene