Figure 2.
Various A. actinomycetemcomitans LPS showed large variation in IL-8 binding affinities independent of the LPS serotype, and whole cells of A. actinomycetemcomitans bound IL-8. (a) The dissociation curves were determined using TRFIA in which the wells were coated with LPS, and the bound recombinant His-tagged IL-8 was detected with Europium-labeled anti-6His-antibody. (b) The Kd values varied between 1.2–17 μM, and the control E. coli and P. aeruginosa LPS showed the lowest affinity for IL-8. (c) Each tested A. actinomycetemcomitans strain bound IL-8 to the cell surface. Binding of IL-8 to whole cells of A. actinomycetemcomitans was studied using TRFIA in which wells were coated with fixed bacterial cells; bound recombinant His-tagged IL-8 (15 μM) was detected with an Europium-labeled anti-6His-antibody. The values (ranging from 400 to 1,200) from negative control experiments, in which His-tagged IL-8 was omitted, were subtracted from the obtained values. There was no statistically significant difference between the IL-8-binding potential of different strains (p = 0.578, Kruskal-Wallis test).