Recently, the Strober lab developed a preclinical model that effectively treated colon cancer in mice by combining immunotherapy and autologous bone marrow transplantation in order to markedly augment the anti-tumor potency of immunotherapy. They used the CT26 colon cancer as the therapeutic target either as a single subcutaneous tumor nodule, as a disseminated tumor in the lungs and peritoneum, or as a metastatic tumor in the liver depending on the route of administration of the tumor cells in BALB/c mice. Mice were vaccinated mice with established primary tumors or disseminated/ metastatic disease with irradiated tumor cells mixed with the adjuvant CpG, and found that vaccination alone had no effect on tumor growth. Similarly radiation conditioning of tumor bearing hosts followed by transplantation of bone marrow and spleen cells or purified T cells and hematopoietic stem cells from unvaccinated donors of the same strain had no effect. In contrast, radiation conditioning of mice followed by transplantation of hematopoietic and immune cells from donors of the same strain vaccinated with tumor cells and CpG cured almost all subcutaneous primary as well as disseminated and metastatic tumors in the hosts. A similar result was obtained after autologous transplantation of hematopoietic and immune cells from tumor bearing mice that had been vaccinated after tumor establishment. Investigation of tumor infiltrating cells showed that the injected donor T cells do not accumulate in the tumors unless the host has been irradiated before injection.