Lytic activity of splenocytes isolated from bm1 mice against blast cells from bm1, B6, or DBA/2J mice. Bm1 mice were killed 35 days after splenocyte transfer of either C57BL/6 (▪) or MIP-1−/− (▦) mice. Splenocytes were stimulated in vitro as indicated and tested for lytic activity in a conventional⁵¹Cr-release assay. This is one of three representative experiments.