Fig. 2

Emergency granulopoiesis occurs following intravenous E. coli (5?10?×?10³ cfu) infection.

(A), The drastic expansion of SB⁺ neutrophils (red arrows) in the CHT of an infected embryo when compared with that treated with PBS at 2 dpi (4 dpf). (B), Calculation of the data obtained for SB⁺ neutrophils at different time points after infection (15.60?±?2.80 vs 28.20?±?5.27; 65.71?±?10.60 vs 55.20?±?4.76; 149.50?±?8.70 vs 77.60?±?9.45; 207.60?±?39.15 vs 128.80?±?15.00; 96.40?±?23.80 vs 56.40?±?6.33 in E. coli vs PBS group at each time point. N?=?8 in each group). (C,D), Fluorescence images (C) and calculation (D) of lyz-GFP⁺ neutrophils in PBS (25.11?±?2.58; N?=?9) or E. coli (16.50?±?1.84; N?=?10) treated larval CHT at 6 hpi. The red signals indicate the bacteria phagocytosed by lyz-GFP⁺ neutrophils (white arrows). (E), The percentage of lyz-GFP⁺ neutrophils that are co-stained with TUNEL at 6 hpi (9.31?±?1.87 vs 0.63?±?0.37 in E. coli vs PBS group. N?=?10 in each group). (F), Time-lapse imaging of an infected Tg(lyz:eGFP) CHT from 1 dpi to 1.5 dpi. Obvious generation, expansion and maturation of lyz-GFP⁺ neutrophils are observed. Scale bars, 20??m. See also Video S4. 4a, 4b and 8a, 8b in (F) showing the dividing lyz-GFP⁺ cells. (G), SB⁺ signals (red arrows) in the runx1 mutant treated by either PBS or E. coli at 2 dpi (4 dpf). (H), WISH of pu.1 (red arrows) in the CHT of an embryo challenged with PBS or E. coli at 2 dpi (4 dpf). (I), The number of the pu.1⁺ myeloid progenitors at different time points after challenge (45.88?±?5.87 vs 59.63?±?4.29; 203.38?±?5.02 vs 79.88?±?8.70; 214.50?±?13.98 vs 78.16?±?6.89 in E. coli vs PBS group at each time point. N?=?8 in each group). Scale bars, 20??m.