Uterus of rodents as site for manifestation of transplantation immunity against transplantable tumors

Tumor homografts in uterine horns of mice and rats were studied to see whether the maintenance of pregnancy depended on peculiar properties of the uterus that make it a favorahle site for foreign grafts. Grafts of transplantable mouse and rat tumors in uteri of hosts of the strain of origin resulted in a high percentage of takes. Homografts of the strain-specific MMC1A and the non-strain-specific MC1A transplantable tumors in uteri of mice of foreign strains resulted in a high percentage of takes 8 days after grafting, but growth of the strain-specific tumor was only transitory. Intrauterine mouse tumor homografts in immunized recipients gave negative results in nonpregnant, pseudopregnant, and unilaterally pregnant mice. Heterografts of mouse tumors in the uteri of nonpregnant or pseudopregnant rats failed to grow. Intrauterine homografts of a rat sarcoma in foreign-strain rats resulted in the same low rate of takes as subcutaneous grafts. It is concluded that the uterine horn is a site at which transplantation immunity can manifest itself. Preliminary data also show that the uterus is a site where homografts can elicit a state of homograft immunity.