Various gram-negative species sequester host cytokines using outer membrane proteins or surface modulation by sulfated polysaccharides. An outer membrane lipoprotein (BilRI) of the periodontal pathogen?Aggregatibacter actinomycetemcomitans?binds several cytokines, including interleukin (IL)-8. Because IL-8 is positively charged at physiological pH, we aimed to determine whether IL-8 interacts with negatively charged lipopolysaccharide (LPS). Binding was investigated using electrophoretic mobility shift assays and microwell-based time-resolved fluorometric immunoassay. LPS from each tested strain of?A. actinomycetemcomitans?(N?=?13),?Pseudomonas aeruginosa?(N?=?1) and?Escherichia coli?(N?=?1) bound IL-8. The Kd?value of the?A. actinomycetemcomitans?LPS-IL-8 interaction varied between 1.2–17?μM irrespective of the serotype and the amount of phosphorus in LPS and was significantly lower than that of the BilRI-IL-8 interaction. Moreover, IL-8 interacted with whole?A. actinomycetemcomitans?cells and outer membrane vesicles. Hence, LPS might be involved in binding of IL-8 to the outer membrane of?A. actinomycetemcomitans. This raises an interesting question regarding whether other gram-negative periodontal pathogens use LPS for IL-8 sequestering?in vivo.