[Tumor cell immunogenicity and T-cell-mediated antitumor immune reactions. Modulation and application to immunotherapy].

Several approaches to increase tumor cell immunogenicity and anti-tumor T-cell reactivity have been reviewed. In contrast to unspecific immune stimulation, the activation of specific T-cell reactivity can lead to long-lasting anti-tumor immunity. In several instances, immunization with modified tumor cells led to the induction of tumor immunity against the original non-modified tumor cells. In our own studies two types of approaches were also effective with the highly metastatic mouse tumor line ESb which carries a weak tumor associated antigen. Postoperative immunization with either virus modified ESb cells or with mutagenized variants of ESb cells led to the survival of a significant proportion of the treated animals. These animals had been cured of their micrometastases and developed long lasting anti-tumor immunity. It is hoped that such modified tumor cells could become useful reagents for tumor immunotherapy, especially in situations where the tumor burden is low. Future efforts should be directed towards testing the effectiveness of immunogenic modified tumor variants in combination with surgery or chemotherapy for treatment of micrometatases.