Aspects of the Immunological Response to Ehrlich Carcinoma in Mice
Ehrlich Carcinoma cells killed by exposure to ultraviolet light were tested to determine their effectiveness as a vaccine. Mice received injections of 4 x 10^6 vaccine cells subcutaneously in their tails and were later challenged with live tumor cells. There was a nine-day latency period before the challenge tumors followed normal development patterns. These results imply that the ultraviolet light killed cells had some antigenic properties characteristic of Ehrlich Carcinoma. Mice bearing solid subcutaneous Ehrlich Carcinoma were subjected to a second subcutaneous challenge of the same tumor. Partial regression of the primary tumors occurred, but, after four days, they began to increase in size again. The secondary tumors did not develop as quickly as control tumors, but once started, they followed a normal growth pattern. This indicates that a secondary immune response can occur in mice already bearing tumor, but the response is not strong enough to bring about rejection of either primary or secondary tumors. Mice were given grafts of isogenic skin carrying solid Ehrlich Carcinoma, or isogenic skin from tumor-bearing mice. Mice in a control group received normal isogenic skin. After grafts had healed, all animals were challenged with subcutaneous injections of Ehrlich Carcinoma. Subsequently, the control group showed a stronger response against the tumor than did either recipients of skin or skin+tumor. These results suggest that surgery had stimulated the immune system, and that the skin and skin+tumor from tumor-bearing donors inhibited that stimulation. Small numbers of animals were used in all three experiments. Therefore, the stated results cannot be considered conclusive.