Immunogenicity of subcellular fractions and molecular species of MuLV-induced tumors. II. Stimulation of syngeneic anti-tumor cell-mediated immune responses by subcellular fractions and molecular species of the Rauscher-virus-induced RBL5 tumor

B. J. Kobrin, D. Naor, B. Y. Klein

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Neoplastic cells that fail to induce anti-tumor immune responses may contain potential immunogenic determinants that are not expressed due to various reasons. Biochemical screening of molecular species derived from cellular fractions of such nonimmunogenic tumors may reveal immunogenic entities that are not expressed in the intact cell. In order to elaborate the technical details of the detection and isolation of macromolecules carrying immunogenic determinants of tumor cells under optimal conditions, the authors subjected RBL5, a known immunogenic tumor of C57BL/6 mice, to this screening method. A RBL5 homogenate was fractionated on a sucrose gradient, and the separated fractions were tested for their ability to induce cytotoxic responses in syngeneic mice. Both the heavy fraction (sucrose density 1.220 g/ml) and the light fraction (sucrose density 1.100 g/ml) induced cytotoxic responses. Splenocytes from mice injected with these fractions differentiated into anti-RBL5 cytotoxic cells when co-cultivated with homologous stimulator cells for 6 days. The light fraction contained high 5'- nucleotidase-specific activity and, therefore, was tentatively defined as the plasma membrane. The immunologic responses induced by the sucrose gradient cellular fractions were significant and specific. Furthermore, these responses were dependent on the numbers of both responder and effector cells. The molecular species of the sucrose gradient immunogenic fractions and of the homogenate of intact tumor cells were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The various gel slices obtained after SDS-PAGE were tested for their ability to induce cytotoxic responses in syngeneic mice. Splenocytes of mice injected with certain gel slices differentiated into anti-RBL5 cells when co-cultivated with RBL5 stimulator cells for 6 days. The cytotoxic responses, which were significant, specific, and reproducible, were dependent on the number of effector cells. The immunogenic molecular species were not represented identically in the light and the heavy fractions or in the cellular homogenate. Finally, macromolecules carrying immunogenic determinants that induced anti-tumor cytotoxic responses were isolated from a normal spleen cell homogenate of C57BL/6 mice.

Original languageEnglish
Pages (from-to)1874-1882
Number of pages9
JournalJournal of Immunology
Volume126
Issue number5
StatePublished - 1981

Fingerprint

Dive into the research topics of 'Immunogenicity of subcellular fractions and molecular species of MuLV-induced tumors. II. Stimulation of syngeneic anti-tumor cell-mediated immune responses by subcellular fractions and molecular species of the Rauscher-virus-induced RBL5 tumor'. Together they form a unique fingerprint.

Cite this