Chemotaxis in single gradients superimposed over isotropic attractant field.

<p>[A] Chemotactic index in a 0–25 nM fMLP gradient over uniform intermediate chemoattractant concentration. The fMLP gradient was fixed for all conditions, while the concentration of the uniform intermediate chemoattractant background was varied from 0 to 10 nM for both IL-8 and LTB₄. 30 cells were tracked for 20 minutes for each experiment. [B] Chemotactic index in 0–25 nM IL-8 and 0–15 nM LTB₄ gradients over uniform concentration of fMLP. All conditions in the left figure consisted of a fixed 0–25 nM IL-8 gradient with a uniform concentration of fMLP, while all conditions on the right had a fixed 0–15 nM LTB₄ gradient with a uniform concentration of fMLP. 30 cells were tracked for each experiment. [C] Chemotactic indices for cells in intermediate chemoattractant gradients over uniform background concentration of alternate intermediate chemoattractant. All conditions in the left figure consisted of a fixed 0–15 nM IL-8 gradient over a varying uniform LTB₄ background, while all conditions in the right figure consisted of a fixed 0–25 nM LTB₄ gradient over a varying uniform IL-8 background.