Altered Host-Allograft Relationships for Mouse Tumors Modified by Prior Passage In Vitro and In Vivo

Summary

Tumors altered by short-term passage in vivo or in vitro were established as serially transplantable lines in untreated allogeneic mice. The allogeneic hosts were modified in turn by the allograft so that, 7 to 8 days after challenge with an altered tumor, they could accept grafts of the conventionally maintained, unaltered tumor counterpart. This was a dynamic tumor-host interrelationship in which the immune reactivity of both graft and recipient was altered. The altered tumors grew in the presence of an early reaction within the host; occasionally the reaction resulted in graft rejection and subsequent immunity to a second challenge. The characteristics of these tumor-host interactions resembled some of those described for both tolerance and enhancement, and in certain instances the same mechanisms might have been operating in all three phenomena.