Tolerance of F 1 Hybrid Skin Homografts in the Parent Strain Induced by Parabiosis. ∗

Summary

1) Tolerance of F₁ hybrid skin homografts in mice of their corresponding parent strains has been attempted by establishing “F₁ to parent” parabiosis. 2) Results were: a) Mice of either Z or Ce strain joined in parabiosis with (Z x Ce) F₁ hybrids became tolerant and accepted skin homografts taken from this hybrid. b) Tolerance of (A x Z)Fi skin was also obtained in Z strain mice following parabiosis with (A x Z)F₁ hybrids. However, A mice joined to the same hybrids failed to develop tolerance and rejected the F₁ grafts in all instances, c) While 20% of Z mice became tolerant of (Z x C₅₇ Bl)F₁ skin after being in parabiosis with this hybrid, none of C₅₇Bl parent parabionts were susceptible of the hybrid skin grafts.