Loss of reactivity of a BALB/c myeoloma tumor with allogeneic and syngeneic cytotoxic T lymphocytes.

It was previously observed that MOPC-315EL, a subline of the BALB/c myeloma tumor MOPC-315, varies in its ability to interact with primary anti-H-2d cytotoxic thymus-derived lymphocytes (CTL) while remaining invariant in its expression of cell surface antigens recognized by anti-H-2d sera. This paper demonstrates (a) that secondary anti-H-2d CTL also fail to recognize the late tumor cells, and (b) that two other CTL systems (anti-minor histocompatibility antigens and anti-2,4,6-trinitrophenyl), which require recognition of both H-2 products and other surface antigens, also fail to react with the late tumor cells. The defect in the late tumor cells was evident when they were used as targets, inhibitors, and stimulators of CTL activity.