Fig. 2
Bovine PMN are unresponsive to Lm formyl peptides, Lm factors released in medium and intact Lm. Data points are color-coded according to the PMN donor cows, as listed in the panel on the upper right. Statistical analyses: Mann–Whitney U tests (**P < 0.01; ***P < 0.001; ****P < 0.0001; ns non-significant). A PMN chemotaxis toward Lm formyl peptides (fMIVIL and fMIVTLF), both tested at concentrations of 1 and 10 nM, in comparison with medium alone and bovine IL-8. Data are represented as means on a superimposed scatter dot plot of 3 independent experiments, each performed in triplicates. B PMN chemotaxis toward WT-Lm suspended in medium (WT-Lm) and heat-killed WT-Lm suspended in medium (HK-Lm), in comparison with PMN chemotaxis toward medium alone and bovine IL-8. Data are represented as means on a superimposed scatter dot plot of 3 independent experiments, each performed in triplicates. C Comparison of CFU collected from the upper well of WT-Lm freely suspended in medium (WT-Lm, black dots) with WT-Lm trapped under agarose (WT-Lm under agarose, white dots). Values are normalized to an inoculum of 105 CFU to allow comparison between experiments. Data are represented as mean ± SEM (standard error of mean) of 2 independent experiments performed in triplicates. D PMN chemotaxis toward WT-Lm trapped under agarose and WT-Lm culture supernatant diluted 1:10 in fresh CAM (WT-Lm culture sup.) in comparison with medium alone and bovine IL-8. Data are represented as means on a superimposed scatter dot plot of 3 independent experiments, each performed in triplicates. E PMN chemotaxis toward WT-Lm opsonized with bovine serum and freely resuspended in medium (Ops. WT-Lm, n = 4), EGDe-Lm freely resuspended in medium (EGDe-Lm, n = 6) and Δhly-Lm freely resuspended in medium (Δhly-Lm, n = 3) in comparison with medium alone (n = 6) and bovine IL-8 (n = 6). Data are represented as means on a superimposed scatter dot plot of 3 to 6 independent experiments, each performed in triplicates. For conditions tested in less than 6 animals, statistical analysis was performed between each condition tested and corresponding donor cows used to assess chemotaxis toward medium alone