Quantitative aspects of the relationship between the tumor and host response.

BACKGROUND

It is generally assumed that the immune response by a host to the tumor depends on their antigenic differences. Whether quantitative aspects in this relationship play any role remains unclear.

MATERIALS AND METHODS

Observation of tumor growth and regression in allogeneic murine models under various experimental conditions.

RESULTS

Prior single inoculation with a tumor without take (apparently insufficient antigenic stimulation for the host) does not confer significant protection from subsequent challenges with the same tumor. Prior take and temporary growth of a tumor followed by regression (sufficient antigenic stimulation) confers absolute immunity to subsequent challenges by the same tumor. Mice with progressive allogeneic tumor growth (sufficient antigenic stimulation), following tumor resection develop absolute immunity to subsequent challenges with the same tumor. Prior immunization with irradiated tumor cells (10(4) - 10(6) SC weekly x 3, i.e. a sufficient antigenic stimulation) confers immunity to subsequent challenges with the same tumor, while immunization with 10(3) irradiated cells weekly x 3 (insufficient antigenic stimulation) does not confer immunity to subsequent challenges with the same tumor.

CONCLUSION

The spontaneous host response to an implanted tumor with weak antigenic differences is usually weak and delayed due to insufficient antigenic stimulation initially of the host, who is perfectly capable in dealing effectively with the same challenges when primed before by a temporary prior growth of this tumor or immunization with the same tumor.