H-2g, a glucose analog of blood group H antigen, mediates monocyte recruitment in vitro and in vivo via IL-8/CXCL8

OBJECTIVE Monocyte (MN) recruitment is an essential inflammatory component of many autoimmune diseases, including rheumatoid arthritis (RA). In this study we investigated the ability of 2-fucosyllactose (H-2g), a glucose analog of blood group H antigen to induce MN migration in vivo and determined if H-2g-induced interleukin-8 (IL-8/CXCL8) plays a role in MN ingress in RA. METHODS Sponge granuloma and intravital microscopy assays were performed to examine H-2g-induced in vivo MN migration and rolling, respectively. MNs were stimulated with H-2g, and the production of IL-8/CXCL8 was assessed by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction. Lastly, in vitro MN migration assays and an in vivo RA synovial tissue severe combined immunodeficiency mouse model were used to determine the role of IL-8/CXCL8 in H-2g-induced MN migration. RESULTS In vivo, H-2g induced significantly greater MN migration compared to phosphate buffered saline. Intravital microscopy revealed that H-2g mediates MN migration in vivo by inducing MN rolling. In addition, H-2g induced MN production of IL-8/CXCL8, a process that was dependent on Src kinase. Moreover, we found that H-2g mediated MN migration in vitro, and in vivo migration was inhibited by a neutralizing anti-IL-8/CXCL8 antibody. CONCLUSION These findings suggest that H-2g mediates MN recruitment in vitro and in vivo (in part) via IL-8/CXCL8.