Uptake of apoptotic neutrophils increases the number of IL-1β producing cells in the infected cell population.

<p>hMDMs were stimulated with FITC labeled γ-irr Mtb at a ratio of 5∶1 (Mtb), with subsequent stimulation with PKH26-labeled PMNapo at a ratio of 2∶1 (Mtb+PMNapo). The hMDMs were stained for intracellular IL-1β (Pacific Blue) and TNFα (Alexa Fluor 647) and analyzed by flow cytometry. (A) The figure shows shows the percentage of hMDMs (based on forward/side scatter) positive for Mtb (FITC/FL-1), PMNapo (PKH26/FL-2) or both. (B) The histograms show the percentage of TNFα (Alexa 647/FL-6) or IL-1β (Pacific Blue/FL-9) positive cells in the population of hMDMs which have phagocytosed both Mtb and PMNapo. (C) The figure shows the number of IL-1β or TNFα producing cells (%) in the following subpopulations; FITC⁻/PKH26⁻ (no uptake), FITC⁻/PKH26⁺ (PMNapo uptake), FITC⁺/PKH26⁻ (Mtb uptake) and FITC⁺/PKH26⁺ (Mtb+PMNapo). (n = 5). Differences between groups are shown as * (p<0.05).