Abstract
The ability of passively-transferred isoantibody to destroy hitherto long-tolerated skin homografts in inbred rats was investigated. A total of about 6.0 ml of isoantiserum, which was directed against the alien histocompatibility antigens of Ag-B locus compatible or incompatible grafts, was injected intraperitoneally over a 7-day period. Control animals received either normal rat serum or serum from rats immunized with sheep red blood cells. Within 12 hr after transfer of specific immune serum to rats bearing Ag-B incompatible grafts, the grafts became inflamed and some developed minor lesions, but excepting those instances in which acute rejections were observed, all grafts subsequently recovered and appeared normal. However, in 10 of 22 (45%) of these animals the grafts underwent total destruction within 49 days after the serum was transferred. Rats whose grafts still survived 50 days after serum transfer were retreated with specific antibody. This increased the number of rejected grafts to 17 of 22 (77%). In contrast with these results, rats tolerant of Ag-B compatible homografts were completely refractory to attempts to terminate the tolerant state, nor did such grafts display any transient inflammatory reaction.
Animals in which tolerance was abolished as a result of immune serum transfer were rechallenged 50 to 100 days later with skin from the original donor strain. These grafts were promptly and consistently rejected, suggesting that although the antibody probably exerted some direct inimical effect on the graft, the abolition of tolerance observed was complete, and was procured by abolition of the chimeric state of the host.
Footnotes
This work was supported in part by United States Public Health Service Grant AI-07001.
