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. Author manuscript; available in PMC: 2019 Jul 22.
Published in final edited form as: J Leukoc Biol. 2019 Jan 28;105(6):1099–1110. doi: 10.1002/JLB.4HI0918-364RR

Figure 2. Neutrophils do not penetrate bacterial biofilms.

Figure 2

C57BL6/N mouse was infected with 1×105 cfu/eye PAO1-GFP. Mice were given fluorescent anti-Ly6G-Alexa 647 IV to label neutrophils. (A) Neutrophil swamps were migrating towards bacterial biofilms (green). Still image from S1. Bar size 72 μm. (B) Meandering indexes were calculated using MatLab and plotted. Neutrophil motilities differed depending on whether neutrophils appeared proximal to the biofilm (white circles) or distal (orange circles). Proximally located PMNs had significantly lower motilities when compared to the ones within the swamps or at a distance where bacteria were planktonic. Student’s t-test. S1 movie is representative of three independent experiments. (C) Crawling neutrophils (blue) probe the bacterial clusters (green) (Still image from S2). P. aeruginosa PAO1 appear green, less mobile, and individual bacterial cells visibly move back and forth demonstrating restricted mobility within microcolonies. The movie displays crawling neutrophils that probe bacterial microcolonies, but do not enter them. The movie is representative of more than three independent experiments. Video recording, 50 min.