Alloreactive donor T cells in recipients undergoing GVHD express no IL-7R.

Lethally irradiated (1300 cGy) CBA/J recipients (3 months old) received B10.BR TCD BM cells (5 × 10⁶) + splenic T cells (0.5 × 10⁶). Osmotic minipumps were used for continuous subcutaneous administration of 1 μg/d IL-7 or PBS (control) from day −1 to day +13. All recipients were humanely killed on day 13 and spleens were harvested and processed for flow cytometric analysis. (A,B) Normal (untransplanted) B10BR splenocytes stained with CD8, CD44, CD122, and CD127 (IL-7Rα). Panel A shows CD127 expression on naive CD8 cells (CD8⁺, CD44⁻). Panel B shows CD127 expression on memory CD8 cells (CD8⁺, CD44⁺, CD122⁺). Panel C demonstrates CD127 expression on memory CD8⁺ T cells from PBS-treated recipients with GVHD. Panel D depicts CD127 expression on memory CD8⁺ T cells from IL-7–treated recipients with GVHD. The vertical lines represent the upper limit of the isotopic Ig controls.