A Transient Cytotoxic Host Response to the Rous Sarcoma Virus-Induced Transplantation Antigen

Abstract

Summary

This report is concerned with the time-relationship of cell-mediated immune reactions by hosts with expanding transplanted solid tumors. Inoculation of 10⁶ serially passaged tumor cells elicited peak lymphocyte cytotoxic responses between 16 and 21 days followed by a state of immunological “paralysis.” Rats which were inoculated with 10⁶ tumor cells which had been passaged four additional times in tissue culture gave lymphocytes with peak cytotoxic effects at 9 days after implantation and “paralysis” by 16 days. A stimulatory effect over and above the normal “feeder” effect by unsensitized lymphoid cells was noted when “paralyzed” cells were overlayed on the target cells. This “paralysis” could not be attributed to a general state of debilitation in the tumor-bearing hosts.