Generation of NK cells.

Flow cytometric analysis of (A)RAG2cγ^−/−and (B) Balb/cRAG2^−/−thymi 2 months after reconstitution with a Pax5^−/−pre-B I–cell clone. (C) Cytotoxic activity of sorted NK1.1⁺CD3⁻ cells was sorted from RAG2cγ^−/−(▴ and ▪) and Balb/c RAG2^−/−(♦ and ●) thymi transplanted 2 months earlier with Pax5^−/−pre-B I–cell clones 4 (▴ and ♦) and 5 (▪ and ●). Sorted cells were activated for 7 days with IL-2 and then were assayed for their cytotoxicity against YAC-1 targets.