HD11 chicken macrophage-like cells.

<p><b>Panel A</b> shows HD11 cells that have not been stimulated with PMA, while <b>Panel B</b> shows HD11 cells 12 hours after stimulation with PMA. Photographs were taken under 10X magnification.</p

List of bacterial strains used in this study.

a<p>Dr. B. Finlay, University of British Columbia, Vancouver, British Colombia.</p>b<p>Dr. C. Poppe, Laboratory for Foodborne Zoonoses, Health Canada, Guelph, Ontario.</p

Wild-type <i>S.</i> Typhimurium strain SL1344 in the media fraction over time.

<p>HD11 cell nuclei are stained blue, both intra- and extracellular bacteria are green, and extracellular bacteria appear red or yellow. <b>Panel A</b> shows an HD11 cell loaded with wild-type <i>S.</i> Typhimurium strain SL1344 at 0.5 h PU, just prior to addition of gentamicin. <b>Panels B</b> and <b>C</b> show whole HD11 cells containing SL1344 at 3 and 6 h PU, respectively, after addition of gentamicin. <b>Panels D</b> and <b>E</b> show fragmented HD11 cells containing SL1344 at 12 and 24 h PU, respectively, after the addition of gentamicin. Whole and fragmented cells containing SL1344 were visible at all time points in the media fraction.</p

Recovery of <i>Salmonella</i> from the cell monolayer fraction of HD11 cells over time.

<p>The ability of SPI-2 mutants (<i>S. </i>Typhimurium Δ<i>ssaR</i> and <i>S.</i> Enteritidis ΔSPI-2) to survive in the chicken macrophage HD11 cell line was compared to their parent wild-type strains (<i>S.</i> Typhimurium SL1344 and <i>S.</i> Enteritidis Sal18) as well as to the non-pathogenic <i>E. coli</i> strain DH5α. <b>Panel A</b> shows the recovered CFU/ml from the cell monolayer fraction at 0.5 h post-uptake (PU), prior to addition of gentamicin. <b>Panels B</b>, <b>C</b>, <b>D</b>, and <b>E</b> show the recovered CFU/ml from the cell monolayer fraction after the addition of gentamicin at 3, 6, 12, and 24 h PU respectively. *, <i>p-</i>value<0.05; **, <i>p</i>-value<0.01; ***, <i>p</i>value<0.001. Note that the scale of the Y-axis is linear, and differs between time points.</p

Hydrogen peroxide production by activated HD11 cells.

<p>Fold difference in hydrogen peroxide production in HD11 cells 12 hours after stimulation with PMA compared to that of unstimulated cells, as measured by luminescence produced by the reaction between hydrogen peroxide, luminal, and HRP.</p