Tumor-Infiltrating Dendritic Cells are Defective in Their Antigen-Presenting Function and Inducible B7 Expression
Many human and experimental cancers express abnormal proteins, including the products of mutated oncogenes, tumor suppressor genes, or viral genes, fusion proteins resulting from translocations, or products of normal but silent genes (1). At least some of these abnormal proteins should be recognized as antigens by T lymphocytes and induce an immune response leading to tumor rejection. However, these antigens are tolerated by the immune system, and tumors, instead of being rejected, progress and ultimately kill their host. Among other mechanisms, a defect in the presentation of tumor antigens to the immune system could explain this tolerance.
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