Fig 1: Il1b is driver of emergency hematopoiesis.(A) Granulocyte, monocyte, and lymphocyte numbers in the blood of Il1a−/−, Il1b−/−, and WT mice 24 hours p.i. (GAS) and in uninfected controls (PBS), as determined using a hematology analyzer. ANOVA with Dunnett’s correction for multiple comparisons, n = 8 to 14 per genotype. **P < 0.01. (B) Neutrophil (CD45+ CD11b+ Ly6Cmed Ly6G+) and monocyte (CD45+ CD11b+ Ly6G− Ly6Chi) percentages (of living cells) in BM from Il1a−/−, Il1b−/−, and WT mice 24 hours p.i. (GAS) and from uninfected controls (PBS), as determined flow cytometry. One-way ANOVA, 10 to 16 per genotype. ****P < 0.0001. (C) Lin− progenitor cells (CD5− CD45R− CD11b− Gr-1− 7-4− Ter-119−) and early lymphoid precursors (LSK) (Lin− Sca-1+ c-Kithi) in BM from Il1a−/−, Il1b−/−, and WT mice 24 hours p.i. (GAS) and from uninfected mice (PBS), as determined by flow cytometry. ANOVA with Dunnett’s correction for multiple comparisons, n = 7 to 10 per genotype. (D) Common myeloid progenitors (CMPs) (Lin− Sca-1− c-Kithi CD16/32lo, CD34+) and granulocyte-macrophage progenitors (GMPs) (Lin− Sca-1− c-Kithi CD16/32hi, CD34lo) in BM from Il1a−/−, Il1b−/−, and WT mice 24 hours p.i. (GAS) and from uninfected controls (PBS), as determined by flow cytometry. ANOVA with Dunnett’s correction for multiple comparisons, n = 7 to 10 per genotype. **P < 0.01. (E and F) G-CSF protein (encoded by the Csf3 gene) (E) and Csf3 mRNA levels (F) at the site of infection from Il1a−/−, Il1b−/−, and WT mice 24 hours p.i. (GAS) and (for Csf3 mRNA) from uninfected controls (PBS), as determined by enzyme-linked immunosorbent assay (ELISA) and reverse transcription quantitative polymerase chain reaction (RT-qPCR), respectively. Kruskal-Wallis with Dunn’s multiple comparisons (E), n = 22 to 24 per genotype. ***P < 0.001; ****P < 0.0001.