REGRESSION OF ESTABLISHED MURINE CARCINOMA METASTASES FOLLOWING VACCINATION WITH TUMOR-ASSOCIATED ANTIGEN PEPTIDES

The cure of micrometastases following surgery is the major goal of can cer immunotherapy. We have recently isolated tumour-associated antigen (TAA) peptides, MUT 1 and MUT 2, derived from a mutated connexin 37 g ap-junction protein, from the malignant 3LL-D122 murine lung carcinoma . We now report that synthetic MUT 1 or MUT 2 induces effective antitu mour cytoxic T lymphocytes. Peptide vaccines protect mice from spontan eous metastases of 3LL-D122 tumours. Moreover, peptide vaccines reduce metastatic loads in mice carrying pre-established micrometastases. Tu mour-specific immunity was primarily mediated by CD8(+) T cells. This is the first evidence that peptide therapy may be effective in treatme nt of residual tumours and provides a rationale for the development of peptide vaccines as a modality for cancer therapy.