Nonimmunogenic tumor cells may efficiently restimulate tumor antigen-specific cytotoxic T cells.

Journal article

Induction of immunity to a viral protein that had been transfected into a tumor cell line was studied. The nucleoprotein (NP) of vesicular stomatitis virus (VSV) was used as a model tumor-associated Ag after transfection into EL-4, and H-2b thymoma originating from C57BL/6 mice. The NP-transfected cell line (EL-4NP) was lysed by NP-specific CTL and was found to restimulate NP-specific CTL in vitro as efficiently as did VSV-infected macrophages. Despite both of these in vitro characteristics, C57BL/6 mice inoculated with EL-4NP did not mount a measurable NP-specific CTL response and developed a lethal tumor as rapidly as did mice given control EL-4. This lack of immunogenicity could not be explained by down-regulation of MHC class I molecules or by loss of NP; even EL-4NP cells metastasizing to the spleen kept their high restimulatory capacity and excellent target characteristics. However, once mice were immunized with VSV or with a vaccinia-VSV-NP recombinant virus they were protected against tumor growth of EL-4NP by CD8+ CTL but not by CD4+ T cells. Taken together, the failure of the tumor-associated Ag to induce a protective T cell response in vivo despite its excellent capacity to restimulate CTL in vitro may encourage adjuvant immunotherapy in cancer; even the effects of weakly immunizing tumor vaccines, e.g., recombinant viruses, may be efficiently amplified by tumor cells.

Authors: Kündig, T; Bachmann, M; Lefrancois, L; Puddington, L; Hengartner, H

• Publication status: Published
• Journal: Journal of Immunology
• Volume: 150
• Issue: 10
• Pages: 4450-4456
• Publication date: 1993-05-01
• EISSN: 1550-6606
• ISSN: 0022-1767
• Language: English
• Keywords: Virus Replication; Thymoma; Vesicular stomatitis Indiana virus; T-Lymphocyte Subsets; Nucleocapsid Proteins; CD4-Positive T-Lymphocytes; Animals; Antigens, Viral; Tumor Cells, Cultured; Nucleoproteins; Mice, Inbred C57BL; Antigens, CD8; Viral Core Proteins; Antigens, Neoplasm; T-Lymphocytes, Cytotoxic; Mice; Neoplasms, Experimental