Stimulation of multiple CD8+ murine tumor infiltrating lymphocyte (TIL) lines and one TIL clone with the tumor of origin of the TIL induced at least three-fold more secretion of TNF and/or INF-gamma than was elicited by other syngeneic, methylcholanthrene (MCA) induced sarcomas. TIL which specifically secreted lymphokines were generated from three different sarcomas. Specific lymphokine secretion was a stable characteristic of the lines over time. IL-2 was necessary for maximal lymphokine secretion by TIL. These investigations demonstrate that lymphokine secretion by CD8+ lymphocytes derived from tumor bearing mice can be used to define unique tumor associated antigens on at least three different sarcomas and may be valuable in studies of the biologic nature of these antigens and of the adoptive immunotherapy of cancer.