Resistance to tolerance induction and age-dependent cellular changes in SJL mice.

SJL mice became resistant to tolerance induction between the 2nd and 6th week of life. The effect on tolerance induction of radioresistant accessory (A) cells does not depend on the age of the donor, i.e. is the same whether the A-cell donor is 3 or 12 weeks old. In the thymectomized recipient, reconstituted with spleen cells of 12-week-old donors, resistance to tolerance is greater than in the corresponding intact animal. Resistance to tolerance is due to a change in the T cells, occurs at a different rate in the T cells of thymus and spleen, and my be due to change in the relative proportion of different T-cell subpopulations.