Membrane-associated properties of four different transplantable lymphomas were studied. All of the lymphomas were θ C3H antigen positive but did not express Thy antigen to equal degrees. The response of the lymphomas to mitogens was found to be variable. DNA synthesis by lymphomas YAC and YACIR was stimulated by PHA but not by concanavalin A (Con A) at concentrations previously shown to be optimal for normal T-lymphocytes. Production of DNA by lymphomas YC8 and LSTRA was suppressed by phytohemagglutinin (PHA) but unchanged by Con A. All of the lymphomas were refractile toward the B-lymphocyte mitogen lipopolysaccharide. Maximal stimulation of YAC lymphoma cells by PHA occurred at somewhat higher concentrations than that producing greatest DNA synthesis by normal lymphocytes. The effect of T-lymphocyte mitogens upon RNA and protein synthesis was also variable. Protein and RNA production by YAC was enhanced by PHA, whereas YC8 produced less RNA and protein when PHA was added to the culture medium. Autoradiographic analysis suggested that PHA stimulated greater numbers of YAC lymphoma cells to enter mitosis while PHA selectively reduced the number of YC8 cells that mitosed. No binding of Con A to lymphoma cells was detected when the lymphomas were incubated with 125I-labeled Con A. The conclusion was drawn that the structures that interact with specific mitogens may be missing or modified on some lymphoma cells.
This work was supported by USPHS Grant CA-15655.