Immunogenicity of Friend Erythroleukemia Cells Altered in Culture by Chemical or Physical Agents

Log-phase-cultured Friend erythroleukemia cells of the FLC-745 line of DBA/2J origin administered either s.c. or i.p. in DBA/2J mice produced survival characteristics that were independent of the route of implantation. The survival time of host animals, however, was dependent on their immunological status. The effects of treatment of cells in culture with a series of glycerol and dihydroxyacetone analogs or of exposure to medium enriched in deuterium oxide on cell proliferation and differentiation in culture and on the tumorigenicity of treated cells transplanted into DBA/2J mice were examined. Animals surviving implantation of a single dose of altered cells were tested for their ability to reject a lethal rechallenge with 106 untreated Friend erythroleukemia cells given 10 to 14 weeks after primary implantation of treated cells. Only a small proportion of animals survived primary challenge with cells exposed to 1-chloro-3-hydroxyacetone benzoate (CIHAB) and related a-halocarbonyl derivatives at concentrations of 10 or 20 μm. Similarly, only a small proportion of animals survived primary challenge with cells attenuated by growth in medium enriched up to 80% in deuterium oxide or by exposure to 3000 rads of X-irradiation. In these cases, where a small proportion of animals survived primary challenge with a single injection of potentially tumorigenic cells, the survivors were completely resistant to rechallenge. A single injection of sonically disrupted Friend cells or of virus harvested from cultured cells had no effect on the survival time of animals subsequently rechallenged with intact Friend erythroleukemia cells. Animals given injections of cells killed by exposure to 50 μm CIHAB in culture exhibited increased survival times upon rechallenge, but only 12% of the animals were completely resistant. In contrast, however, although Friend erythroleukemia cells treated for 3 hr in culture with 30 μM CIHAB were nonproliferative in subculture and completely nontumorigenic when implanted either i.p. or s.c. into DBA/2J hosts, animals receiving a single injection of 106 cells altered in this way were fully protected against rechallenge. Thus, carefully controlled modification of Friend erythroleukemia cells by exposure to a relatively low but sharply defined concentration of CIHAB abrogated tumorigenicity of the treated cells without altering their ability to confer protection to subsequent rechallenge with unaltered cells.