ELISPOT analysis of cytokine production in response to donor (B10.A), host (B6), and third-party (B10.RIII) alloantigens by day 28 splenocytes of mixed chimeras receiving no DLI or DLIs on day 21 after BMT. Results of 2 similar experiments are shown. Each symbol represents an individual animal. The upper panel shows IL-2–producing cells, the middle panel shows IL-4–producing cells, and the lower panel shows IFN-γ–producing cells among SPCs from control naive B6 mice (n=3; ▪), naive B10.A mice (n=3; *), chimeras receiving DLI on day 21 (DLI day 21; n=9; ▾) or not receiving DLI (no DLI; n=6; ○). Chimeric SPCs were collected on day 28. The in vitro stimulators are listed from left to right: medium (background in the absence of stimulator cells in vitro), B6, B10.A, and B10.RIII.