Adoptive immunity in mice challenged with L1210/DTIC clones

Area of Science:

• Immunology
• Oncology
• Cancer Research

Background:

• New antigenic specificities can be induced in mouse lymphomas by 5(3,3-dimethyl-1-triazeno)imidazole-4-carboxamide (DTIC).
• These induced antigens are transmissible and heritable after drug withdrawal.
• The precise mechanism, molecular nature, and number of these specificities remain unclear.

Purpose of the Study:

• To investigate the immunogenicity and antigenic characteristics of DTIC-treated murine leukemia L1210 sublines.
• To determine if DTIC induces new, detectable antigens on leukemia cells.
• To analyze the inheritance and expression of these induced antigens.

Main Methods:

• Four clones of murine leukemia L1210 were treated in vivo with DTIC.
• The resulting sublines were studied for immunogenicity in syngeneic animals.
• Adoptive transfer of spleen cells was used to assess cross-protection in immunosuppressed mice.

Main Results:

• DTIC-treated sublines (A/DTIC, P/DTIC, Q/DTIC, R/DTIC) exhibited strong immunogenicity and were rejected by syngeneic hosts.
• Specific reciprocal cross-protection was observed between A/DTIC and P/DTIC, and between Q/DTIC and R/DTIC.
• No cross-protection was found between the two pairs of sublines, indicating distinct antigenic sets.

Conclusions:

• The parental L1210 leukemia line lacks detectable antigenic cells.
• Four DTIC-induced antigenic sublines were successfully generated and demonstrated immunogenicity.
• Two mutually exclusive sets of antigens were expressed by the four DTIC-treated antigenic clone sublines.