Periodic fluctuations in resistance of a myeloma tumor (MOPC-315-EL) to cytotoxic T lymphocytes. III. Changes in susceptibility of the tumor cells as they grow in nude mice and in culture

We have previously reported that MOPC-315-EL, a myeloma subline of MOPC-315, periodically becomes reversibly altered in its reactivity with both syngeneic and allogenic cytotoxic T lymphocytes (CTLs). In this report we demonstrate that the change from the reactive to the unreactive phenotype can take place in BALB/c nude mice and in culture with essentially the same kinetics and to the same degree as that which occurs in conventional BALB/c mice. The reactive and unreactive MOPC-315-EL cells obtained from nude mice or grown in culture express identical amounts of the serologically defined H-2^d antigens, as determined by quantitative adsorptions of anti-H-2^d antibodies, suggesting that non-H-2 components determine the unreactive phenotype. The change in reactivity with T cells does not require that MOPC-315-EL cells undergo division, but it does appear to be dependent upon certain growth factors.