Accumulation of LSKF cells in the absence of p65 is due to cell intrinsic factors. (A) 5 × 10⁶ whole bone marrow cells from wild-type or p65^hem−/− mice were injected into lethally irradiated recipients. Twenty weeks after transplant, the frequency of bone marrow LSKF cells was monitored by flow cytometry (n = 5). All recipients displayed >98% CD45.2⁺ peripheral blood cells. (B) 3 × 10⁶ whole bone marrow cells from Mx1-Cre⁺p65^fl/fl mice or littermate controls were transplanted into lethally irradiated recipients. Four weeks after transplant (engraftment of >95% CD45.2 cells), recipients were injected with 250 μg poly(I:C) 3 times, every other day. Twenty-nine weeks after induction, the frequency of bone marrow CD45.2⁺ LSKF cells was analyzed by flow cytometry (n = 6). p65 expression was examined in whole bone marrow cells from animals receiving poly(I:C) by (C) quantitative reverse transcriptase-polymerase chain reaction and (D) immunoblot. *P ≤ .005. (E) Bone marrow was harvested from nontransgenic animals treated with an IKKβ inhibitor (compound A) 16 hours after the last injection and analyzed by flow cytometry (n = 3 NT, n = 6 DMSO and CpA).