Tumor Vaccination With Cytokine-Loaded Microspheres

摘要

A single intra-tumoral injection of IL-12 + GM-CSF-encapsulated microspheres promoted the suppression of primary tumor growth prevented the development of additional tumors and extended survival in the her2-neu transgenic FVB/neuN murine mammary tumor model. Induction of a long-lived systemic tumor-specific immune response was demonstrated in adoptive cell transfer studies cytotoxic T-cell assays in vivo lymphocyte subset depletion studies and analysis of serum anti-tumor antibody levels. Repeated treatment was more effective than single treatment in inducing complete tumor regression secondary tumor suppression and enhancing survival however long-term cures were not obtained. Chemoimmunotherapy did not improve long-term survival. Further analysis of tumor-infiltrating T-cells demonstrated that repeated therapy resulted in the enhancement of T-suppressor cell activity and the loss of tumor- specific cytotoxic T-lymphocytes.