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Tumor-associated antigens of rat moloney sarcoma cells. I. Cell-surface antigens
Abstract:
The dissociated cell surface membranes of a rat Moloney sarcoma (MST), derived from a BN rat, were extracted with 2 M KI, with 6 M guanidine thiocyanate, or by papain digestion. Extracts obtained with these three reagents were fractionated on columns of controlled-pore glass, 170 A pore size. A fraction was eluted from each preparation that contained tumor-associated antigens (TAA), viral, fetal, and histocompatibility antigens. With an antibody specific for TAA, the TAA, devoid of detectable viral, fetal, and histocompatibility antigens, were co-precipitated by addition of goat antibody to rat immunoglobulin. After electrophoresis, on slab gels, three bands were detected with estimated m.w. of 185,000, 150,000, and 70,000. No such bands were detected on slab gel electrophoresis with extracts of BC5, a chemically induced tumor, of normal BN lymphoid cells, of M-MuLV, or of fetuses, after incubation with anti-TAA antibody and goat antibody to rat immunoglobulin. TAA extracts prepared with 2 M KI, 6 M guanidine thiocyanate, or papain digestion showed immunologic reactivity. Cold TAA inhibited the co-precipitation of labeled TAA by rat antibody specific for TAA; they elicited antibody in guinea pigs but not in rats; and antibodies specific for TAA were cytotoxic to MST in the presence of C.
Insights
Researchers isolated tumor-associated antigens (TAA) from rat sarcoma membranes. These purified TAA, distinct from viral or fetal proteins, showed specific immunologic reactivity and potential for cancer diagnostics.
Area of Science:
- Immunology
- Oncology
- Biochemistry
Background:
- Moloney sarcoma (MST) is a rat tumor model.
- Tumor-associated antigens (TAA) are potential targets for cancer therapy and diagnostics.
- Characterizing TAA requires effective isolation and purification methods.
Purpose of the Study:
- To isolate and characterize tumor-associated antigens (TAA) from rat Moloney sarcoma (MST).
- To determine if isolated TAA are distinct from viral, fetal, and histocompatibility antigens.
- To assess the immunologic reactivity of the purified TAA.
Main Methods:
- Extraction of cell surface membranes from MST using 2 M KI, 6 M guanidine thiocyanate, or papain digestion.
- Fractionation of extracts using controlled-pore glass chromatography.
- Co-precipitation with anti-TAA antibody and subsequent slab gel electrophoresis.
- Immunologic assays including inhibition of co-precipitation, antibody elicitation, and complement-dependent cytotoxicity.
Main Results:
- A fraction containing TAA, free of detectable viral, fetal, and histocompatibility antigens, was isolated.
- Electrophoresis revealed three distinct protein bands with molecular weights of 185,000, 150,000, and 70,000.
- These purified TAA demonstrated immunologic reactivity, including eliciting antibodies in guinea pigs and being cytotoxic to MST cells.
Conclusions:
- Tumor-associated antigens (TAA) can be effectively isolated from Moloney sarcoma (MST) using chemical or enzymatic extraction methods.
- The purified TAA are immunologically distinct from other cellular antigens.
- These findings support the potential of TAA as specific targets in cancer research and immunotherapy.