Previous investigation of the
transplantation immunity of 2 cultured murine colon lines of BALB/c origin, C-C36 and C-C26, showed these
tumor lines to be immunogenic against individual
tumors and to have possibly cross-reactive,
tumor-rejection-type
antigens. For characterization of the molecular features of
tumor-rejection
antigens expressed on the colon
tumor cells,
n-butanol was used for the extraction of rejection-type
antigens from
tumor cells and immunogenic molecules were analyzed on
transplantation immunity. The data demonstrated that extraction of the rejection-type
antigens from C-C36 and C-C26 surface membrane without cellular lysis was possible with
n-butanol treatment of these cells, and immunogenic activities of these extracts from C-C36 and C-C26 cells were more potent than those of nonionic
detergent Nonidet P40 extracts in the
tumor-rejection assays. The extracts were partially characterized by chromatographic separation on
Sephadex G-200 gel filtration and
lectin-affinity chromatography. It was suggested that the C-C36
antigens responsible for
tumor-rejection activity against the same
tumor cells had a molecular weight range of approximately 150,000 to 250,000 (fraction II) in the presence of 5 mM
EDTA and had been eluted into unbound fractions to
lens culinaris lectin on affinity chromatography. Moreover, immunization of mice with
antigens from the same fractions (fraction II) of
n-butanol extracts of C-C26
tumor on the gel filtration could induce the resistance against challenged C-C36 as well as against challenged C-C26
tumor growth. These results may indicate that solubilized
tumor-rejection-type
antigens found in C-C36 and C-C26 colon
tumors have a size similar to that of the molecules and that cross-reacting, rejection-type
antigens between these cells are the products of the same gene clusters or somatic derivatives of a single gene.