Transfected Mouse Melanoma Lines That Express Various Levels of Human Melanoma-Associated Antigen p97

Abstract

The gene for the human melanoma-associated antigen p97 has been introduced by cDNA transfection into cells from clone M2 of the K1735 mouse melanoma, which metastasizes to the lung when injected iv into syngeneic C3H/HeN mice. Tumor clones were established from the transfected cells and found to differ in the level of p97 expression. Their outgrowth in immuno-competent syngeneic mice was shown to inversely correlate with p97 antigen expression, and lines that express higher p97 levels elicited a stronger delayed-type hypersensitivity response when injected into the footpads of mice immune to p97. Five clones which expressed very high levels of p97 failed to grow in immunocompetent C3H/HeN mice, while they formed tumors in nude (nu/nu) mice. The highest expressing clone, 2A, grew slightly faster than any of the other clones when cultured in vitro. Since several of the transfected clones were found to express a stable level of p97 and have consistent in vivo growth behavior, they provide a useful model for various forms of antigen-specific active and passive immunotherapy with the same agents as those intended for human application. [J Natl Cancer Inst 81:445–448, 1989]