Tracks of neutrophil migration from old and young healthy subjects. The images show the final neutrophil positions within the Insall chemotaxis chamber following 20 minutes of time-lapse recording of neutrophils from an old (A) or a young (B) donor. The chemoattractant source (CXCL8) was added at the top of the viewing field, creating a gradient diffusing down to the bottom of the viewing field. The tracks (shown in black) indicate the path of migration for each cell analyzed: each track begins where the cell was positioned at the start of recording and ends where the cell was positioned at the end of recording. Each image is representative of all recordings taken of neutrophils from each group for all chemoattractants tested. Bars represent 10 μm (A-B). Images were taken using a Zeiss Axiovert 100 microscope, magnification ×20 (A-B). Migration pathway arrows were generated using ImageJ software on manual tracking.