Effect of stimulation of T cells or APCs on the inhibition of MLRs.

Splenocytes were harvested on day 10 after transplantation from 2 CTLA4Ig-treated or 2 control LEW.1A rats that received LEW.1W heart transplants, and proliferation was assessed on days 3 and 5 of culture. MLRs were performed in the presence of L-NMMA (5 mM) and in the presence or absence of IL-2 (100 U/mL). Stimulation of T cells was performed using anti-CD28 agonistic antibodies. Stimulation of APCs was performed using TRANCE-CD8 or CD40L-CD8. Results are expressed as delta (allogeneic − spontaneous) cpm ± SD and are representative of 2 experiments with a total of 3 animals per group. Each curve represents the proliferation of cells from a single animal.