(A) Adherent, IL-8 treated primary human neutrophils were treated with (left group) anti-CD11b (44a; gray bar) or isotype control (white bar), or (right group) A. caninum neutrophil inhibitory factor (NIF) (gray bar) or PBS vehicle control (white bar; UT = untreated). The percent of neutrophils with intracellular Ngo was calculated using imaging flow cytometry as in Fig. 2. Results are presented as the mean ± SEM for 3 biological replicates, with statistical significance determined by Student’s t test for the appropriate pairs. ** P ≤ 0.01. (B) HL-60 human promyelocytic cells expressing human CD11b that is full-length (FL) or lacking the I-domain (I-less), or carrying empty vector (Vector), were exposed to CFSE-labeled Δopa Ngo for 1 hr. Cells were fixed, stained for extracellular Ngo, and processed for imaging flow cytometry. The percent of CFSE+ HL-60 cells with intracellular Ngo was calculated for 3 biological replicates. Results are presented as the mean ± SEM. Comparisons trended towards but did not reach statistical significance as analyzed using one-way ANOVA.