Specific tumor immunity induced with soluble materials: purification of antigens inducing tumor resistance
Pellis, N.R.; Shulan, D.J.; Kahan, B.D.
Biochemical and Biophysical Research Communications 71(4): 1251-1258
The tumor-specific transplantation antigen (TSTA) in crude 3M KCl extracts of a chemically-induced mouse fibrosarcoma was purified by ammonium sulfate salt fraction at 20% saturation (S20S) and polyacrylamide gel electrophoresis (PAGE). Mice, which were pretreated with the S20S precipitate, displayed retarded outgrowth of a 100-fold supralethal dose of the corresponding, but not a noncross reactive syngeneic tumor. Analysis of PAGE gels by Coomassie blue staining revealed at least 30 bands in the crude 3M KCl extract, and only 2 components (Rf 0.34 and 0.43) in the ammonium sulfate fraction. That these 2 components bore TSTA activity was demonstrated by the observation that the immunoprotective activity of crude 3M KCl extracts was localized to the Rf 0.25-0.50 region. The 2 components present in the S20S fraction had isoelectric points of 5.05 and 6.9, and estimated molecular weights of 40,000 and 75,000, demonstrating the soluble nature of the active principle. These findings offer the prospect of a chemical dissection of the polymorphic TSTA surface markers on MCA/[methylcholanthrene]-induced murine tumors.