Murine B16 melanoma, CT26 colon carcinoma and A20 B cell lymphoma lines were purchased from American Type Culture Collection. Mouse dendritic DC2.4 cells were originally from Dr. Kenneth Rock (University of Massachusetts Medical School, MA). Highly metastatic clone of K1735 melanoma (C4) was kindly provided by Drs. S. Huang and J. Fidler of M. D. Anderson Cancer Center (Houston, TX). The stably transduced A20-Luc cell line was provided by Dr. Defu Zheng (City of Hope, Duarte, CA). The generation of transgenic C57BL/6.CEA mice and MC-38.CEA cell line was previously described 50 .