RT Journal Article SR Electronic T1 Induction of Nitric Oxide Production in RAW264.7 Cells under Serum-free Conditions by O-antigen Polysaccharide of Lipopolysaccharide JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 2875 OP 2879 VO 33 IS 7 A1 TAKESHI KADOWAKI A1 SHIHO OHNO A1 YOSHIE TANIGUCHI A1 HIROYUKI INAGAWA A1 CHIE KOHCHI A1 GEN-ICHIRO SOMA YR 2013 UL http://ar.iiarjournals.org/content/33/7/2875.abstract AB Background: Lipopolysaccharide derived from Pantoea agglomerans (LPSp) mainly consists of two aggregates, the high-molecular aggregate (HMM-LPSp) and the low-molecular aggregate (LMM-LPSp). The structural differences between HMM-LPSp and LMM-LPSp seem to depend on the length of the O-antigen polysaccharide because the lipid A regions of the two fractions are quite similar. In this study, we examined the biological activity of LPSp focusing on the O-antigen polysaccharide using HMM-LPSp and LMM-LPSp under serum-free conditions. Materials and Methods: The binding of LPSp to RAW264.7 cells under serum-free conditions was analyzed by flow cytometry using LPSp-conjugated fluorescein isothiocyanate (FITC-LPSp). The biological activities of HMM-LPSp and LMM-LPSp under serum-free conditions were evaluated by the nitric oxide production. Results: FITC-LPSp showed higher fluorescence intensity under serum-free than serum-containing conditions. HMM-LPSp induced higher nitric oxide production than LMM-LPSp under serum-free conditions. Conclusion: The present study indicates that the reactivity of LPSp is affected by the O-antigen polysaccharide under serum-free conditions.