Fig. 3

Caspase-8 deficiency alters the macrophage TLR response in vivo but does not affect cell survival. a Splenocytes from 6–8-month-old (aged) female Casp8 ^fl/fl (control) and Cre ^LysM Casp8 ^fl/fl mice (n ≥ 7) were analyzed by flow cytometry. Shown are representative fluorescence-activated cell sorting (FACS) plots of splenic CD11b⁺F4/80⁺Ly6C^high and CD11b⁺F4/80⁺Ly6C^low populations displaying relative levels of TLR expression. b and c Representative FACS plots and quantitative graphs of results representing the fold change in CD86 expression over PBS injection alone. b 3-month-old control and Cre ^LysM Casp8 ^fl/fl mice (n = 4) that received LPS or CpG injection (200 μg/mouse) were evaluated 4 h later for splenic CD11b⁺F4/80⁺Ly6C^high cell expression of CD86. c Serum levels of cytokines and chemokines from TLR agonist–injected mice. d and e 3-week-old control and Cre ^LysM Casp8 ^fl/fl mice (n = 4) treated with oral antibiotics (ampicillin, vancomycin, neomycin sulfate, metronidazole) for 8 weeks were evaluated for d spleen weight and e cervical lymph node weight. f–l Mice reconstituted with equal portions of B6.CD45.1 (wild-type [WT]) and either control or Cre ^LysM Casp8 ^fl/fl FACS-sorted LSK populations (n = 5) were maintained on low-dose oral antibiotics. f Representation of chimera generation. Chimeric mice were evaluated 8 months posttransfer for g splenomegaly, h lymphadenopathy, i proteinuria, j serum cytokine and chemokine levels, k myeloid cell subset numbers, and l distribution of WT (45.1)-derived and control or Cre ^LysM Casp8 ^fl/fl (45.2)-derived myeloid populations. Data are represented as mean ± SD and were compared by Mann–Whitney U test: *p < 0.05; **p < 0.005; ***p < 0.0005. TLR Toll-like receptor, Casp8 caspase-8, LPS lipopolysaccharide, PBS phosphate-buffered saline, IL interleukin, Gro-α growth-regulated oncogene-α, IFN interferon, Ig immunoglobulin, KC keratinocyte chemoattractant, TNF tumor necrosis factor, sRANKL soluble receptor activator of nuclear factor κB ligand, LN lymph node, WT wild type, MCP monocyte chemoattractant protein, LSK lineage-negative, Sca-1⁺, c-kit⁺