INHIBITION OF LUNG COLONIZATION OF A MOUSE MAMMARY-CARCINOMA BY THERAPEUTIC VACCINATION WITH INTERFERON-ALPHA GENE-TRANSDUCED TUMOR-CELLS

A spontaneously metastatic murine mammary adenocarcinoma, TSA, has bee n transduced with the gene for interferon alpha 1 (IFN-alpha). Transfe ctants were used for the immunotherapy of mice bearing lung colonies i nduced by the intravenous inoculation of non-transduced parental cells . A significant reduction in the number of tumor colonies was obtained when repeated subcutaneous administrations of mitomycin C-blocked tra nsfectant cells were given, commencing 3 days after an intravenous cha llenge with TSA cells. Intraperitoneal vaccination induced a stronger anti-tumor response than subcutaneous vaccination, and the proportion of tumor-free mice reached 50%. The potency of IFN-alpha transfectants was similar to that of IFN-gamma transfectants previously obtained fr om TSA. Admixture of IFN-alpha and IFN-gamma transfectant cells in the same vaccine did not increase the curative effect over that of single vaccines. In nude mice vaccination with IFN-alpha or IFN-gamma transf ectants did not lead to a reduction in the number of lung colonies, in dicating that an intact T cell response was required for the therapeut ic effect observed in immunocompetent mice. (C) Rapid Science Ltd.